Early 18F-FAPI PET/CT Imaging for Breast Cancer Diagnosis: A Prospective Comparison with Conventional Imaging Protocols

Early 18F-FAPI PET/CT Imaging for Breast Cancer Diagnosis: A Prospective Comparison with Conventional Imaging Protocols | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Article Early 18 F-FAPI PET/CT Imaging for Breast Cancer Diagnosis: A Prospective Comparison with Conventional Imaging Protocols Zonglin Li, Guohong Lin, Kaiwen Luo, Xiangru Li, Futian Hu, Zheng Zhao, and 5 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7636266/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 08 Dec, 2025 Read the published version in Scientific Reports → Version 1 posted 12 You are reading this latest preprint version Abstract 18 Fluorine ( 18 F) labeled inhibitors of fibroblast activation protein( 18 F-FAPI) PET/CT is an emerging molecular imaging technique suitable for patients with breast cancers(BC). However, some patients may not tolerate the long waiting time after injection, making it crucial to assess whether early imaging can provide sufficient clinical diagnostic information. In this prospective study, 40 patients with suspected BC underwent dual-phase 18 F-FAPI PET/CT at ~10 minutes (early) and ~60 minutes (conventional) post-injection. The diagnostic performance of both protocols was compared in differentiating benign from malignant lesions. A total of 51 breast lesions were detected, and SUVmax and lesion-to-background ratio (LBR) were obtained by outlining ROIs. After the PET/CT scan, all lesions underwent tissue biopsy, with 36 being BC and 15 benign breast lesions (BBL) . The results showed a significant difference in SUVmax between early and conventional imaging (p=0.001), but no significant difference in LBR (p=0.456). The FAPI uptake in the BC group was significantly higher than in the BBL group. The cutoff values for SUVmax were 3.62 for early imaging and 4.12 for conventional imaging, while the cutoff values for LBR were 4.42 for early imaging and 4.34 for conventional imaging. At the optimal cutoff values, early imaging with SUVmax achieved the highest diagnostic performance, with an AUC of 1.00, and both sensitivity and specificity of 100%. The AUC for LBR was 0.93, with a sensitivity of 86.1% and specificity of 86.7%. No significant difference in diagnostic performance was found between early and conventional imaging (DeLong test; SUVmax p=0.48 and LBR p=0.25). Our findings indicate that early 18 F-FAPI PET/CT imaging offers diagnostic accuracy comparable to conventional imaging while significantly reducing acquisition time, supporting its potential as a practical alternative in clinical practice. Biological sciences/Cancer Health sciences/Medical research Health sciences/Oncology FAPI PET/CT Breast cancer Early imaging SUVmax LBR Figures Figure 1 Figure 2 Figure 3 Introduction Breast cancer (BC) is the most commonly diagnosed cancer worldwide, representing a major global health challenge[1]. According to the American Cancer Society's 2025 global cancer statistics, BC accounts for approximately 32% of all female cancers, with its annual incidence increasing by about 1% over the past decade[2]. In clinical practice, ultrasound-guided core needle biopsy or surgical excision is routinely performed for suspicious breast lesions[3,4]. However, the positivity rate of these procedures remains relatively low (19.5%–42.7%)[5], resulting in many patients undergoing unnecessary surgeries and being exposed to risks such as infection, tumor dissemination, and bleeding[6]. Fibroblast activation protein inhibitor (FAPI) is a novel class of molecular probes targeting fibroblast activation protein (FAP), which is highly expressed in the tumor stroma but minimally expressed in normal tissues[7]. This property confers high tumor affinity and excellent tumor-to-background contrast, thereby enabling effective PET/CT imaging across a range of malignancies[8-10]. Both our group and recent studies have demonstrated that FAPI PET/CT achieves high sensitivity and specificity in diagnosing breast cancer[11-13]. Nevertheless, most existing studies focus on conventional imaging performed approximately 60 minutes after tracer injection. Such prolonged waiting may be impractical for patients unable to tolerate the delay. To investigate the feasibility of early 18 F-FAPI PET/CT imaging in BC, we retrospectively compared early imaging (approximately 10 minutes post-injection) with conventional imaging (approximately 60 minutes post-injection) in 40 patients with suspicious BCs. We assessed the diagnostic performance of both imaging protocols in differentiating BC from benign breast lesions (BBL), aiming to determine whether early imaging could serve as a practical alternative to conventional protocols. Materials and methods Patient characteristics This prospective observational study was conducted at The Second Affiliated Hospital of Guangxi Medical University from February 2024 to July 2025. A total of 44 female patients with ultrasound-detected breast lesions classified as BI-RADS category 4 or 5 were prospectively enrolled. All patients underwent dual-phase ¹⁸F-FAPI PET/CT imaging, which included both early-phase and conventional-phase acquisitions. Prior to PET/CT imaging, none of the patients had received any treatment, including surgery, chemotherapy, radiotherapy, or immunotherapy. Histopathological diagnoses were obtained through biopsy or surgical resection, both performed after PET/CT imaging. Four patients were excluded due to concurrent primary malignancies (n=2) or intolerance to prolonged imaging (n=2). Ultimately, 40 patients were included in the final analysis. Written informed consent was obtained from all participants. None of the patients were pregnant or lactating at the time of imaging. The study protocol was approved by the Ethics Committee of the Second Affiliated Hospital of Guangxi Medical University (Approval No. 2024-KY0013) and was conducted in accordance with the Declaration of Helsinki. 18 F-FAPI PET/CT Imaging The ¹⁸F-FAPI-04 radiotracer was supplied by Nanning Yuanzi Gaoke Co., Ltd. (Nanning, China). PET/CT scans were performed using a Siemens Biograph Sensation 16 scanner (Siemens, Erlangen, Germany). Patients were not required to undergo any special preparation prior to imaging. The radiotracer was administered intravenously at a dose of 3.7 MBq/kg body weight. Whole-body PET/CT images were acquired at 10 minutes and 60 minutes post-injection, corresponding to early and conventional imaging, covering the area from the vertex to the mid-thigh. Image evaluation All PET images were independently interpreted by two nuclear medicine experts, each with over ten years of diagnostic experience in nuclear medicine. Discrepancies in interpretation were resolved by consensus through joint review. In cases where the localization of breast lesions was unclear, confirmation and re-localization were performed by an experienced breast ultrasound specialist with over 10 years of clinical experience. Regions of interest (ROIs) were delineated on both early and conventional fused PET/CT axial images by an experienced nuclear medicine physician. ROIs corresponding to breast lesions were defined based on their morphological contours. Additional ROIs were delineated within the background breast tissue, situated in the ipsilateral breast within 10 mm of the lesion margin, and defined as circular areas with a radius of 5 mm.Semi-quantitative analysis was performed on the PET/CT images to obtain the maximum standardized uptake value (SUVmax) of the breast lesions and the mean standardized uptake value (SUVmean) of the background tissue. The lesion-to-background ratio (LBR) was calculated by dividing the SUVmax of the lesion by the SUVmean of the background. Statistical analysis Statistical analyses were conducted using SPSS software (version 26.0; IBM Corp., Armonk, NY, USA). Quantitative variables were presented as mean ± standard deviation (SD) and median with interquartile range (IQR), while categorical variables were summarized as counts and percentages [n (%)]. The Wilcoxon signed-rank test was used to compare semi-quantitative parameters (SUVmax, SUVmean, and LBR) between early and conventional imaging. Receiver operating characteristic (ROC) curve analysis was performed to determine optimal cut-off values for each dual-time-point parameter, with sensitivity, specificity, area under the curve (AUC), and Youden index calculated. The DeLong test was applied to compare differences in AUC between early and conventional imaging for the same parameter. A p-value < 0.05 was considered statistically significant. Results Lesion detection A total of 51 lesions were identified in the study cohort. Patient characteristics are summarized in Table 1. The lesions were classified using the ultrasound BI-RADS system as follows: category 4a (18/51, 35%), category 4b (12/51, 24%), category 4c (14/51, 27%), and category 5 (7/51, 14%). Histopathological analysis confirmed BC (36/51, 70.6%) and BBL (15/51, 29.4%). All lesions were clearly visualized on both early and conventional 18 F-FAPI PET/CT. The SUVmax of lesions We compared the SUVmax of breast lesions in early and conventional PET/CT imaging (Table 2). Among 51 lesions, 21.5% (11/51) showed higher SUVmax in early imaging, while 78.5% (40/51) exhibited higher SUVmax in conventional imaging. Overall, SUVmax was significantly higher in conventional imaging than in early imaging (median values of 7.93 vs. 6.66; Wilcoxon test: p = 0.001). When grouped by pathology, conventional imaging in the BC group showed significantly higher SUVmax than early imaging (median values of 10.21 vs. 9.02; Wilcoxon test: p = 0.003). In the BBL group, conventional imaging had a slightly higher SUVmax, but the difference was not significant (median values of 1.62 vs. 1.23; Wilcoxon test: p = 0.135). In both early and conventional imaging, the SUVmax in the BC group was significantly higher than that in the BBL group (Fig. 1A). Fig. 2 presents the typical imaging manifestations of BC and BBL in early and conventional 18 F-FAPI PET/CT imaging. Background and LBR In early imaging, the SUVmean of the background breast tissue was significantly lower than that in conventional imaging (median 0.69 vs. 0.87; Wilcoxon test: p = 0.002) (Table 3). Overall, the LBR in early imaging was numerically higher than that in conventional imaging; however, the difference was not statistically significant (median 7.05 vs. 5.77; Wilcoxon test: p = 0.456). In the BC group, no significant difference in LBR was observed between early and conventional imaging (median 11.63 vs. 11.72; Wilcoxon test: p = 0.369). Similarly, in the BBL group, early and conventional imaging showed no significant difference in LBR (median 1.87 vs. 2.62; Wilcoxon test: p = 0.89). Fig. 1B illustrates the comparison of LBR between breast cancer and benign breast lesion patients in early versus conventional imaging. Receiver Operating Characteristic Curve We evaluated the discriminative performance of SUVmax and LBR in differentiating BC from BBL using both early and conventional imaging (Fig. 3; Table 4). The AUC values for these two parameters were as follows: SUVmax (1.00 vs. 0.99, DeLong test: p = 0.48) and LBR (0.93 vs. 0.97, DeLong test: p = 0.25). No significant differences in diagnostic performance were observed between early and conventional imaging for either parameter, both of which demonstrated strong discriminative ability. Notably, early imaging with SUVmax achieved perfect diagnostic accuracy (AUC=1.00, sensitivity=100%, specificity=100%). Discussion This study aimed to compare the diagnostic value of early (10-minute) and conventional (60-minute) 18 F-FAPI PET/CT imaging in distinguishing between benign and malignant high-risk breast lesions. The results demonstrated that both early and conventional imaging showed low radiotracer uptake in normal breast tissue, while BC exhibited significantly higher uptake, allowing for clear delineation of the lesion boundaries. Further analysis revealed that, in the dual-phase imaging, the SUVmax and LBR of BC were significantly higher than those of BBL, suggesting that both imaging phases have good diagnostic discrimination capabilities. Although a difference in SUVmax was observed between early and conventional imaging, this did not have a substantial impact on the overall diagnostic performance of 18 F-FAPI PET/CT in distinguishing malignant from benign lesions. Several studies have explored dual-phase FAPI imaging in various tumors. Chen et al.[ 14 ] found no significant difference in SUVmax between ultra-early (5 minutes) and conventional (60 minutes) imaging in patients with pancreatic and gastric cancers. Ferdinandus et al.[ 15 ] similarly observed no significant difference in SUVmax between 10-minute and 60-minute imaging in a study involving 69 patients with various malignant tumors. Hoppner et al.[ 16 ] noted that there was no significant difference in pancreatic lesion detection rate between early (20 minutes) and conventional (60 minutes) imaging in 33 patients with pancreatic cancer. These findings are consistent with our study, suggesting that early 18 F-FAPI PET/CT imaging provides reliable and sufficient imaging information for clinical use. LBR, which reflects the contrast between the lesion and surrounding background tissue, is an important indicator of lesion visibility. The higher the LBR, the better the visibility of the lesion[ 17 ]. In our study, early imaging of breast cancer showed higher LBR, indicating that the lesion could be visualized well in the early imaging. However, this result contrasts with the findings of Jiang et al.[ 18 ] in head and neck tumors. Jiang et al. reported that delayed imaging (120 minutes) showed a significantly higher LBR compared to early imaging (30 minutes). The discrepancy could be attributed to our choice of breast tissue as the reference background, as normal breast tissue in early imaging phases has a relatively low uptake, thus enhancing the contrast of the lesion. Current conventional imaging techniques for breast cancer include mammography, ultrasound, and MRI. While mammography and ultrasound are simple, quick, and cost-effective, their diagnostic accuracy is limited, with sensitivities of approximately 75%-85% for mammography[ 19 ] and an average accuracy of about 73.64% for ultrasound[ 20 ]. MRI shows higher sensitivity (92%-95%) and good specificity (78%-80%) in breast cancer diagnosis[ 21 , 22 ], but its application is limited by long scan times, high costs, and contraindications in patients with metal implants. In contrast, our study confirms that early 18 F-FAPI PET/CT shows exceptional diagnostic efficacy in distinguishing suspicious breast cancer lesions, with both sensitivity and specificity reaching 100%, and the area under the curve (AUC) was 1. These results are highly consistent with the study by Kömek et al.[ 13 ] (sensitivity 100%, specificity 95.6%). As an emerging imaging modality, early 18 F-FAPI PET/CT offers the advantage of significantly shortened scanning time while maintaining excellent diagnostic performance, providing an efficient imaging option for clinical practice. This not only helps to improve early breast cancer diagnosis rates but may also reduce unnecessary invasive procedures (e.g., biopsy or surgery), thereby lowering the risk of infection, tumor dissemination, and other potential complications. However, there are certain limitations to this study. First, this is a single-center, small sample size study, which may introduce selection bias. Second, the imbalance in the number of breast cancer and benign breast lesion cases could impact the sensitivity and specificity evaluation of SUVmax and LBR. Therefore, future larger-scale, multi-center prospective studies are necessary to further validate the clinical utility of early 18 F-FAPI PET/CT in the diagnosis of breast lesions, as well as to explore its potential role in disease classification, staging, and treatment efficacy evaluation. Conclusion Both early and conventional 18 F-FAPI PET/CT demonstrated excellent diagnostic performance in suspected breast cancer. Given its comparable accuracy and shorter acquisition time, early imaging represents a promising and patient-friendly alternative to conventional protocols, with the potential to streamline clinical workflow and reduce unnecessary biopsies. Statements & Declarations Data Availability The datasets generated during and/or analysed during the current study are available from the corresponding author on reasonable request. Author Contributions All authors contributed to the study conception and design. Material preparation, data collection and analysis were performed by [Zonglin Li], [Shidong Lian] and [Kaiwen Luo]. The first draft of the manuscript was written by [Zonglin Li] and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript. Funding The authors declare that no funds, grants, or other support were received during the preparation of this manuscript. Competing Interests The author(s) declare no competing interests. Ethics approval This study was performed in line with the principles of the Declaration of Helsinki. Approval was granted by the Ethics Committee of the Second Affiliated Hospital of Guangxi Medical University (Date2024/2/19/No2024-KY(0013)) Consent to participate Informed consent was obtained from all individual participants included in the study. Consent to publish The authors affirm that human research participants provided informed consent for publication of the images in Figure(s) 2A-2F. References Duggan C, Trapani D, Ilbawi AM, Fidarova E, Laversanne M, Curigliano G, et al. National health system characteristics, breast cancer stage at diagnosis, and breast cancer mortality: a population-based analysis. Lancet Oncol. 22(11), 1632-1642 (2021). US Preventive Services Task Force; Nicholson WK, Silverstein M, Wong JB, Barry MJ, Chelmow D, Coker TR, et al . Screening for Breast Cancer: US Preventive Services Task Force Recommendation Statement. JAMA . 11;331(22):1918-1930 (2024). 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Evaluation of FAPI PET imaging in gastric cancer: a systematic review and meta-analysis. Theranostics . 13(13):4694-4710 (2023). Jacobson FL, Van den Abbeele AD. Importance of 68Ga-FAPI PET/CT for Detection of Cancer. Radiology . 303(1):200-201 (2022). Elboga U, Sahin E, Kus T, Cayirli YB, Aktas G, Uzun E,et al. Superiority of 68 Ga-FAPI PET/CT scan in detecting additional lesions compared to 18 FDG PET/CT scan in breast cancer. Ann Nucl Med. 35(12):1321-1331 (2021). Sahin E, Kus T, Aytekin A, Uzun E, Elboga U, Yilmaz L, et al. 68 Ga-FAPI PET/CT as an Alternative to 18 F-FDG PET/CT in the Imaging of Invasive Lobular Breast Carcinoma. J Nucl Med. 65(4):512-519 (2024). Kömek H, Can C, G ü zel Y, Oruç Z, G ü ndo ğ an C, Yildirim ÖA, et al. 68 Ga-FAPI-04 PET/CT, a new step in breast cancer imaging: a comparative pilot study with the 18 F-FDG PET/CT. Ann Nucl Med. 35(6):744-752 (2021). Chen R, Yang X, Yu X, Zhou X, Ng YL, Chen Y, et al. 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Tables Table 1 Patient characteristics N=36 Overall Age (years) Mean (SD) 52.03 ± 13.22 Sex Females 40 (100%) Weight (kg) Mean (SD) 59.02 ± 9.30 Administered dose (MBq) Mean (SD) 7.08 ± 1.12 Pathological diagnosis BC 36 (70.6%) Invasive ductal carcinoma 32 (62.7%) Ductal carcinoma in situ 2 (3.9%) Invasive/Infiltrating micropapillary carcinoma 1 (2%) Breast encapsulated papillary carcinoma 1 (2%) BBL 15 (29.4%) Fibroadenoma of breast 7 (13.7%) Adenosis of breast 5 (9.8%) Intraductal papilloma 3 (5.9%) Table 2 Comparison of 18 F-FAPI-04 uptake between early imaging and conventional imaging Variables Early imaging Conventional imaging P SUVmax of all lesions Mean (SD) 7.63 ± 5.55 8.25 ± 5.85 Median (IQR) 6.66(2.97, 11.34) 7.93(2.52, 12.47) 0.001 SUVmax of BC Mean (SD) 10.19 ± 4.55 10.99 ± 4.70 Median (IQR) 9.02(6.57, 13.04) 10.21(7.62, 13.01) 0.003 SUVmax of BBL Mean (SD) 1.49 ± 1.01 1.65 ± 0.93 Median (IQR) 1.23(0.71, 1.92) 1.62(1.01, 1.94) 0.135 Table 3 Background and lesion-to-background ratios Variables Early imaging Conventional imaging P SUVmean of breast Mean (SD) 0.89 ± 0.65 1.04 ± 0.87 Median (IQR) 0.69(0.44, 1.14) 0.87(0.58, 1.48) 0.002 LBR of all lesions Mean (SD) 13.50 ± 16.55 11.07 ± 11.85 Median (IQR) 7.05(2.91, 14.97) 5.77(3.21, 14.62) 0.456 LBRc of BC Mean (SD) 18.01 ± 17.84 14.71 ± 12.40 Median (IQR) 11.63(6.11, 21.05) 11.72(5.16, 19.63) 0.396 LBRc of BBL Mean (SD) 2.67 ± 2.14 2.34 ± 1.21 Median (IQR) 1.87(1.51, 2.69) 2.62(1.40, 3.21) 0.89 Table 4 Diagnostic performance of semi-quantitative parameters Variables Time phase Cutt off AUC(95% CI) Sensitivity(%) Specificity(%) Youden’s Index DeLong z p SUVmax Early 3.62 1(1-1) 100% 100% 1.00 0.71 0.48 Conventional 4.12 0.99(0.99-1) 97.2% 100% 0.97 LBR Early 4.42 0.93(0.86-1) 86.1% 86.7% 0.73 1.14 0.25 Conventional 4.34 0.97(0.93-1) 88.9% 100% 0.89 Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 08 Dec, 2025 Read the published version in Scientific Reports → Version 1 posted Editorial decision: Revision requested 07 Oct, 2025 Reviews received at journal 06 Oct, 2025 Reviews received at journal 28 Sep, 2025 Reviewers agreed at journal 25 Sep, 2025 Reviews received at journal 21 Sep, 2025 Reviewers agreed at journal 21 Sep, 2025 Reviewers agreed at journal 20 Sep, 2025 Reviewers invited by journal 20 Sep, 2025 Editor invited by journal 19 Sep, 2025 Editor assigned by journal 18 Sep, 2025 Submission checks completed at journal 17 Sep, 2025 First submitted to journal 17 Sep, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. 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10:05:19","extension":"xml","order_by":9,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":71591,"visible":true,"origin":"","legend":"","description":"","filename":"fb5b395d17a946f785c1781dd82a95831structuring.xml","url":"https://assets-eu.researchsquare.com/files/rs-7636266/v1/a8ac14f43ade565a10f82626.xml"},{"id":92583131,"identity":"2f16b718-5670-45f2-a03e-62ea0d002871","added_by":"auto","created_at":"2025-10-01 10:05:19","extension":"html","order_by":10,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":80828,"visible":true,"origin":"","legend":"","description":"","filename":"earlyproof.html","url":"https://assets-eu.researchsquare.com/files/rs-7636266/v1/848a91f981c3f9c520bcee7f.html"},{"id":92584976,"identity":"a3d977f6-ec1f-4b0c-bf74-82a07e241ebf","added_by":"auto","created_at":"2025-10-01 10:21:19","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":103877,"visible":true,"origin":"","legend":"\u003cp\u003eThe SUVmax and LBR of suspected breast cancer lesions in early \u003csup\u003e18\u003c/sup\u003eF-FAPI PET/CT imaging and conventional imaging. The uptake values are shown in both individual lesion data (as a dot-line graph) and overall distribution (as a box plot), providing insights into lesion specificity and general trends. \u003cstrong\u003eA/B\u003c/strong\u003e display the differences in SUVmax and LBR between the BC group and the BBL group under dual-phase imaging. The results indicate that, in both early and conventional imaging, SUVmax and LBR of BC lesions were significantly higher than those of BBL lesions (p \u0026lt; 0.001). \u003cstrong\u003eC/D\u003c/strong\u003e illustrate the distribution of individual differences between early and conventional imaging, suggesting that FAPI uptake fluctuation in breast cancer is markedly higher than in benign breast lesions.\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-7636266/v1/64db000c4bee1c09b241c312.png"},{"id":92583127,"identity":"c46f77e3-a025-49ae-9f8f-a5a6c0e60ccc","added_by":"auto","created_at":"2025-10-01 10:05:19","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":283758,"visible":true,"origin":"","legend":"\u003cp\u003e\u0026nbsp;The characteristic imaging features of high-risk breast lesions on early and delayed-phase \u003csup\u003e18\u003c/sup\u003eF-FAPI PET/CT. \u003cstrong\u003eA/D\u003c/strong\u003e are CT images; \u003cstrong\u003eB/E\u003c/strong\u003e are early imaging fused images; \u003cstrong\u003eC/F\u003c/strong\u003e are conventional imaging fused images. \u003cstrong\u003eA–C\u003c/strong\u003e A 35-year-old patient diagnosed with invasive ductal carcinoma, as indicated by the red arrow, with ultrasound findings classified as BI-RADS 4a. In the early and conventional imaging the SUVmax(12.51 VS 14.22), LBR(22.22 VS 22.22), respectively. \u003cstrong\u003eD–F\u003c/strong\u003e A 51-year-old patient with a breast fibroadenoma, as indicated by the white arrow, also categorized as BI-RADS 4a. In the early and conventional imaging the SUVmax(0.52 VS 1.10), LBR(2.17 VS 2.62), respectively.These findings demonstrate that both SUVmax and LBR in BC are markedly higher than those in BBL across both imaging phases.\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-7636266/v1/f7382e4e1bdf7b4f1bf21cfd.png"},{"id":92584555,"identity":"615de31e-b0e9-4e7a-8025-cbd10dc64b87","added_by":"auto","created_at":"2025-10-01 10:13:19","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":26869,"visible":true,"origin":"","legend":"\u003cp\u003eROC curves for distinguishing BC and BBL based on early and conventional \u003csup\u003e18\u003c/sup\u003eF-FAPI PET/CT imaging. (A) shows SUVmax, (B) shows LBR.\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-7636266/v1/721b18c464efe07e585c141e.png"},{"id":98243474,"identity":"5652cc93-10e3-4c51-97a4-c00b6016ef4b","added_by":"auto","created_at":"2025-12-15 16:05:35","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2442416,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7636266/v1/630b963e-66bd-49d6-ad25-c8dbdb99220b.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"\u003cp\u003eEarly \u003csup\u003e18\u003c/sup\u003eF-FAPI PET/CT Imaging for Breast Cancer Diagnosis: A Prospective Comparison with Conventional Imaging Protocols\u003c/p\u003e","fulltext":[{"header":"Introduction","content":"\u003cp\u003eBreast cancer (BC) is the most commonly diagnosed cancer worldwide, representing a major global health challenge[1]. According to the American Cancer Society's 2025 global cancer statistics, BC accounts for approximately 32% of all female cancers, with its annual incidence increasing by about 1% over the past decade[2]. In clinical practice, ultrasound-guided core needle biopsy or surgical excision is routinely performed for suspicious breast lesions[3,4]. However, the positivity rate of these procedures remains relatively low (19.5%–42.7%)[5], resulting in many patients undergoing unnecessary surgeries and being exposed to risks such as infection, tumor dissemination, and bleeding[6].\u003c/p\u003e\n\u003cp\u003eFibroblast activation protein inhibitor (FAPI) is a novel class of molecular probes targeting fibroblast activation protein (FAP), which is highly expressed in the tumor stroma but minimally expressed in normal tissues[7]. This property confers high tumor affinity and excellent tumor-to-background contrast, thereby enabling effective PET/CT imaging across a range of malignancies[8-10]. Both our group and recent studies have demonstrated that FAPI PET/CT achieves high sensitivity and specificity in diagnosing breast cancer[11-13]. Nevertheless, most existing studies focus on conventional imaging performed approximately 60 minutes after tracer injection. Such prolonged waiting may be impractical for patients unable to tolerate the delay.\u003c/p\u003e\n\u003cp\u003eTo investigate the feasibility of early \u003csup\u003e18\u003c/sup\u003eF-FAPI PET/CT imaging in BC, we retrospectively compared early imaging (approximately 10 minutes post-injection) with conventional imaging (approximately 60 minutes post-injection) in 40 patients with suspicious BCs. We assessed the diagnostic performance of both imaging protocols in differentiating BC from benign breast lesions (BBL), aiming to determine whether early imaging could serve as a practical alternative to conventional protocols.\u003c/p\u003e"},{"header":"Materials and methods","content":"\u003cp\u003e\u003cstrong\u003ePatient characteristics\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis prospective observational study was conducted at The Second Affiliated Hospital of Guangxi Medical University from February 2024 to July 2025. A total of 44 female patients with ultrasound-detected breast lesions classified as BI-RADS category 4 or 5 were prospectively enrolled. All patients underwent dual-phase \u0026sup1;⁸F-FAPI PET/CT imaging, which included both early-phase and conventional-phase acquisitions. Prior to PET/CT imaging, none of the patients had received any treatment, including surgery, chemotherapy, radiotherapy, or immunotherapy. Histopathological diagnoses were obtained through biopsy or surgical resection, both performed after PET/CT imaging.\u003c/p\u003e\n\u003cp\u003eFour patients were excluded due to concurrent primary malignancies (n=2) or intolerance to prolonged imaging (n=2). Ultimately, 40 patients were included in the final analysis. Written informed consent was obtained from all participants. None of the patients were pregnant or lactating at the time of imaging. The study protocol was approved by the Ethics Committee of the Second Affiliated Hospital of Guangxi Medical University (Approval No. 2024-KY0013) and was conducted in accordance with the Declaration of Helsinki.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003csup\u003e18\u003c/sup\u003e\u003c/strong\u003e\u003cstrong\u003eF-FAPI PET/CT Imaging\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe \u0026sup1;⁸F-FAPI-04 radiotracer was supplied by Nanning Yuanzi Gaoke Co., Ltd. (Nanning, China). PET/CT scans were performed using a Siemens Biograph Sensation 16 scanner (Siemens, Erlangen, Germany). Patients were not required to undergo any special preparation prior to imaging. The radiotracer was administered intravenously at a dose of 3.7 MBq/kg body weight. Whole-body PET/CT images were acquired at 10 minutes and 60 minutes post-injection, corresponding to early and conventional imaging, covering the area from the vertex to the mid-thigh.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eImage evaluation\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll PET images were independently interpreted by two nuclear medicine experts, each with over ten years of diagnostic experience in nuclear medicine. Discrepancies in interpretation were resolved by consensus through joint review. In cases where the localization of breast lesions was unclear, confirmation and re-localization were performed by an experienced breast ultrasound specialist with over 10 years of clinical experience. Regions of interest (ROIs) were delineated on both early and conventional fused PET/CT axial images by an experienced nuclear medicine physician. ROIs corresponding to breast lesions were defined based on their morphological contours. Additional ROIs were delineated within the background breast tissue, situated in the ipsilateral breast within 10 mm of the lesion margin, and defined as circular areas with a radius of 5 mm.Semi-quantitative analysis was performed on the PET/CT images to obtain the maximum standardized uptake value (SUVmax) of the breast lesions and the mean standardized uptake value (SUVmean) of the background tissue. The lesion-to-background ratio (LBR) was calculated by dividing the SUVmax of the lesion by the SUVmean of the background.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eStatistical analysis\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eStatistical analyses were conducted using SPSS software (version 26.0; IBM Corp., Armonk, NY, USA). Quantitative variables were presented as mean \u0026plusmn; standard deviation (SD) and median with interquartile range (IQR), while categorical variables were summarized as counts and percentages [n (%)]. The Wilcoxon signed-rank test was used to compare semi-quantitative parameters (SUVmax, SUVmean, and LBR) between early and conventional imaging. Receiver operating characteristic (ROC) curve analysis was performed to determine optimal cut-off values for each dual-time-point parameter, with sensitivity, specificity, area under the curve (AUC), and Youden index calculated. The DeLong test was applied to compare differences in AUC between early and conventional imaging for the same parameter. A p-value \u0026lt; 0.05 was considered statistically significant.\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003eLesion detection\u003c/p\u003e\n\u003cp\u003eA total of 51 lesions were identified in the study cohort. Patient characteristics are summarized in Table 1. The lesions were classified using the ultrasound BI-RADS system as follows: category 4a (18/51, 35%), category 4b (12/51, 24%), category 4c (14/51, 27%), and category 5 (7/51, 14%). Histopathological analysis confirmed BC (36/51, 70.6%) and BBL (15/51, 29.4%). All lesions were clearly visualized on both early and conventional \u003csup\u003e18\u003c/sup\u003eF-FAPI PET/CT.\u003c/p\u003e\n\u003cp\u003eThe SUVmax of lesions\u003c/p\u003e\n\u003cp\u003eWe compared the SUVmax of breast lesions in early and conventional PET/CT imaging (Table 2). Among 51 lesions, 21.5% (11/51) showed higher SUVmax in early imaging, while 78.5% (40/51) exhibited higher SUVmax in conventional imaging. Overall, SUVmax was significantly higher in conventional imaging than in early imaging (median values of 7.93 vs. 6.66; Wilcoxon test: p = 0.001). When grouped by pathology, conventional imaging in the BC group showed significantly higher SUVmax than early imaging (median values of 10.21 vs. 9.02; Wilcoxon test: p = 0.003). In the BBL group, conventional imaging had a slightly higher SUVmax, but the difference was not significant (median values of 1.62 vs. 1.23; Wilcoxon test: p = 0.135). In both early and conventional imaging, the SUVmax in the BC group was significantly higher than that in the BBL group (Fig. 1A).\u003c/p\u003e\n\u003cp\u003eFig. 2\u0026nbsp;presents the typical imaging manifestations of BC and BBL in early and conventional \u003csup\u003e18\u003c/sup\u003eF-FAPI PET/CT imaging.\u003c/p\u003e\n\u003cp\u003eBackground and LBR\u003c/p\u003e\n\u003cp\u003eIn early imaging, the SUVmean of the background breast tissue was significantly lower than that in conventional imaging (median 0.69 vs. 0.87; Wilcoxon test: p = 0.002) (Table 3).\u003c/p\u003e\n\u003cp\u003eOverall, the LBR in early imaging was numerically higher than that in conventional imaging; however, the difference was not statistically significant (median 7.05 vs. 5.77; Wilcoxon test: p = 0.456). In the BC group, no significant difference in LBR was observed between early and conventional imaging (median 11.63 vs. 11.72; Wilcoxon test: p = 0.369). Similarly, in the BBL group, early and conventional imaging showed no significant difference in LBR (median 1.87 vs. 2.62; Wilcoxon test: p = 0.89). Fig. 1B illustrates the comparison of LBR between breast cancer and benign breast lesion patients in early versus conventional imaging.\u003c/p\u003e\n\u003cp\u003eReceiver Operating Characteristic Curve\u003c/p\u003e\n\u003cp\u003eWe evaluated the discriminative performance of SUVmax and LBR in differentiating BC from BBL using both early and conventional imaging (Fig. 3; Table 4). The AUC values for these two parameters were as follows: SUVmax (1.00 vs. 0.99, DeLong test: p = 0.48) and LBR (0.93 vs. 0.97, DeLong test: p = 0.25). No significant differences in diagnostic performance were observed between early and conventional imaging for either parameter, both of which demonstrated strong discriminative ability. Notably, early imaging with SUVmax achieved perfect diagnostic accuracy (AUC=1.00, sensitivity=100%, specificity=100%).\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eThis study aimed to compare the diagnostic value of early (10-minute) and conventional (60-minute) \u003csup\u003e18\u003c/sup\u003eF-FAPI PET/CT imaging in distinguishing between benign and malignant high-risk breast lesions. The results demonstrated that both early and conventional imaging showed low radiotracer uptake in normal breast tissue, while BC exhibited significantly higher uptake, allowing for clear delineation of the lesion boundaries. Further analysis revealed that, in the dual-phase imaging, the SUVmax and LBR of BC were significantly higher than those of BBL, suggesting that both imaging phases have good diagnostic discrimination capabilities. Although a difference in SUVmax was observed between early and conventional imaging, this did not have a substantial impact on the overall diagnostic performance of \u003csup\u003e18\u003c/sup\u003eF-FAPI PET/CT in distinguishing malignant from benign lesions.\u003c/p\u003e\u003cp\u003eSeveral studies have explored dual-phase FAPI imaging in various tumors. Chen et al.[\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e] found no significant difference in SUVmax between ultra-early (5 minutes) and conventional (60 minutes) imaging in patients with pancreatic and gastric cancers. Ferdinandus et al.[\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e] similarly observed no significant difference in SUVmax between 10-minute and 60-minute imaging in a study involving 69 patients with various malignant tumors. Hoppner et al.[\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e] noted that there was no significant difference in pancreatic lesion detection rate between early (20 minutes) and conventional (60 minutes) imaging in 33 patients with pancreatic cancer. These findings are consistent with our study, suggesting that early \u003csup\u003e18\u003c/sup\u003eF-FAPI PET/CT imaging provides reliable and sufficient imaging information for clinical use.\u003c/p\u003e\u003cp\u003eLBR, which reflects the contrast between the lesion and surrounding background tissue, is an important indicator of lesion visibility. The higher the LBR, the better the visibility of the lesion[\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. In our study, early imaging of breast cancer showed higher LBR, indicating that the lesion could be visualized well in the early imaging. However, this result contrasts with the findings of Jiang et al.[\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e] in head and neck tumors. Jiang et al. reported that delayed imaging (120 minutes) showed a significantly higher LBR compared to early imaging (30 minutes). The discrepancy could be attributed to our choice of breast tissue as the reference background, as normal breast tissue in early imaging phases has a relatively low uptake, thus enhancing the contrast of the lesion.\u003c/p\u003e\u003cp\u003eCurrent conventional imaging techniques for breast cancer include mammography, ultrasound, and MRI. While mammography and ultrasound are simple, quick, and cost-effective, their diagnostic accuracy is limited, with sensitivities of approximately 75%-85% for mammography[\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e] and an average accuracy of about 73.64% for ultrasound[\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. MRI shows higher sensitivity (92%-95%) and good specificity (78%-80%) in breast cancer diagnosis[\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e, \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e], but its application is limited by long scan times, high costs, and contraindications in patients with metal implants. In contrast, our study confirms that early \u003csup\u003e18\u003c/sup\u003eF-FAPI PET/CT shows exceptional diagnostic efficacy in distinguishing suspicious breast cancer lesions, with both sensitivity and specificity reaching 100%, and the area under the curve (AUC) was 1. These results are highly consistent with the study by K\u0026ouml;mek et al.[\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e] (sensitivity 100%, specificity 95.6%). As an emerging imaging modality, early \u003csup\u003e18\u003c/sup\u003eF-FAPI PET/CT offers the advantage of significantly shortened scanning time while maintaining excellent diagnostic performance, providing an efficient imaging option for clinical practice. This not only helps to improve early breast cancer diagnosis rates but may also reduce unnecessary invasive procedures (e.g., biopsy or surgery), thereby lowering the risk of infection, tumor dissemination, and other potential complications.\u003c/p\u003e\u003cp\u003eHowever, there are certain limitations to this study. First, this is a single-center, small sample size study, which may introduce selection bias. Second, the imbalance in the number of breast cancer and benign breast lesion cases could impact the sensitivity and specificity evaluation of SUVmax and LBR. Therefore, future larger-scale, multi-center prospective studies are necessary to further validate the clinical utility of early \u003csup\u003e18\u003c/sup\u003eF-FAPI PET/CT in the diagnosis of breast lesions, as well as to explore its potential role in disease classification, staging, and treatment efficacy evaluation.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eBoth early and conventional \u003csup\u003e18\u003c/sup\u003eF-FAPI PET/CT demonstrated excellent diagnostic performance in suspected breast cancer. Given its comparable accuracy and shorter acquisition time, early imaging represents a promising and patient-friendly alternative to conventional protocols, with the potential to streamline clinical workflow and reduce unnecessary biopsies.\u003c/p\u003e"},{"header":"Statements \u0026 Declarations","content":"\u003cp\u003e\u003cstrong\u003eData Availability\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe datasets generated during and/or analysed during the current study are available from the corresponding author on reasonable request.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor Contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll authors contributed to the study conception and design. Material preparation, data collection and analysis were performed by [Zonglin Li], [Shidong Lian] and [Kaiwen Luo]. The first draft of the manuscript was written by [Zonglin Li] and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that no funds, grants, or other support were received during the preparation of this manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting Interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe author(s) declare no competing interests.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthics approval\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study was performed in line with the principles of the Declaration of Helsinki. Approval was granted by the Ethics Committee of the Second Affiliated Hospital of Guangxi Medical University (Date2024/2/19/No2024-KY(0013))\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eInformed consent was obtained from all individual participants included in the study.\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent to publish\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eThe authors affirm that human research participants provided informed consent for publication of the images in Figure(s) 2A-2F.\u003c/em\u003e\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n \u003cli\u003e\u003cstrong\u003eDuggan C, Trapani D, Ilbawi AM, Fidarova E, Laversanne M, Curigliano G, et al. 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Dual-Time Point \u003csup\u003e68\u003c/sup\u003eGa-FAPI-04 PET/CT Improves Tumor Delineation and Cervical Lymph Node Metastasis Identification in Patients With Head and Neck Squamous Cell Carcinoma. \u003cem\u003eClin Nucl Med\u003c/em\u003e. 50(3):e130-e137 (2025).\u0026nbsp;\u003c/strong\u003e\u003c/li\u003e\n \u003cli\u003e\u003cstrong\u003eWoo OH, Song SE, Choe SJ, Kim M, Cho KR, Seo BK. Invasive Breast Cancers Missed by AI Screening of Mammograms. \u003cem\u003eRadiology\u003c/em\u003e. 315(3):e242408 (2025).\u0026nbsp;\u003c/strong\u003e\u003c/li\u003e\n \u003cli\u003e\u003cstrong\u003eGao L, Li J, Gu Y, Ma L, Xu W, Tao X, et al. Breast ultrasound in Chinese hospitals: A cross-sectional study of the current status and influencing factors of BI-RADS utilization and diagnostic accuracy. \u003cem\u003eLancet Reg Health West Pac.\u003c/em\u003e Aug 27;29:100576 (2022).\u0026nbsp;\u003c/strong\u003e\u003c/li\u003e\n \u003cli\u003e\u003cstrong\u003ePetrovi\u003c/strong\u003e\u003cstrong\u003eć\u003c/strong\u003e\u003cstrong\u003e\u0026nbsp;D,\u0026nbsp;\u003c/strong\u003e\u003cstrong\u003e\u0026Scaron;ć\u003c/strong\u003e\u003cstrong\u003eepanovi\u003c/strong\u003e\u003cstrong\u003eć\u003c/strong\u003e\u003cstrong\u003e\u0026nbsp;B, Spirovski M, Nikin Z, Prvulovi\u003c/strong\u003e\u003cstrong\u003eć\u003c/strong\u003e\u003cstrong\u003e\u0026nbsp;Bunovi\u003c/strong\u003e\u003cstrong\u003eć\u003c/strong\u003e\u003cstrong\u003e\u0026nbsp;N. Comparative Diagnostic Efficacy of Four Breast Imaging Modalities in Dense Breasts: A Single-Center Retrospective Study. \u003cem\u003eBiomedicines.\u003c/em\u003e 13(7):1750 (2025).\u0026nbsp;\u003c/strong\u003e\u003c/li\u003e\n \u003cli\u003e\u003cstrong\u003eK\u003c/strong\u003e\u003cstrong\u003e\u0026uuml;\u003c/strong\u003e\u003cstrong\u003ehn JP, Hernando D, Mensel B, Kr\u003c/strong\u003e\u003cstrong\u003e\u0026uuml;\u003c/strong\u003e\u003cstrong\u003eger PC, Ittermann T, Mayerle J, et al. Quantitative chemical shift-encoded MRI is an accurate method to quantify hepatic steatosis. \u003cem\u003eJ Magn Reson Imaging.\u0026nbsp;\u003c/em\u003e39(6):1494-501 (2014).\u003c/strong\u003e\u003c/li\u003e\n\u003c/ol\u003e"},{"header":"Tables","content":"\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 568px;\"\u003e\n \u003cp\u003eTable 1 \u0026nbsp;Patient characteristics\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 387px;\"\u003e\n \u003cp\u003eN=36\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 181px;\"\u003e\n \u003cp\u003eOverall\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 387px;\"\u003e\n \u003cp\u003eAge (years)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 181px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 387px;\"\u003e\n \u003cp\u003eMean (SD)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 181px;\"\u003e\n \u003cp\u003e52.03 \u0026plusmn; 13.22\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 387px;\"\u003e\n \u003cp\u003eSex\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 181px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 387px;\"\u003e\n \u003cp\u003eFemales\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 181px;\"\u003e\n \u003cp\u003e40 (100%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 387px;\"\u003e\n \u003cp\u003eWeight (kg)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 181px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 387px;\"\u003e\n \u003cp\u003eMean (SD)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 181px;\"\u003e\n \u003cp\u003e59.02 \u0026plusmn; 9.30\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 387px;\"\u003e\n \u003cp\u003eAdministered dose (MBq)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 181px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 387px;\"\u003e\n \u003cp\u003eMean (SD)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 181px;\"\u003e\n \u003cp\u003e7.08 \u0026plusmn; 1.12\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 387px;\"\u003e\n \u003cp\u003ePathological diagnosis\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 181px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 387px;\"\u003e\n \u003cp\u003eBC\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 181px;\"\u003e\n \u003cp\u003e36 (70.6%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 387px;\"\u003e\n \u003cp\u003eInvasive ductal carcinoma\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 181px;\"\u003e\n \u003cp\u003e32 (62.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 387px;\"\u003e\n \u003cp\u003eDuctal carcinoma in situ\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 181px;\"\u003e\n \u003cp\u003e2 (3.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 387px;\"\u003e\n \u003cp\u003eInvasive/Infiltrating micropapillary carcinoma\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 181px;\"\u003e\n \u003cp\u003e1 (2%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 387px;\"\u003e\n \u003cp\u003eBreast encapsulated papillary carcinoma\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 181px;\"\u003e\n \u003cp\u003e1 (2%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 387px;\"\u003e\n \u003cp\u003eBBL\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 181px;\"\u003e\n \u003cp\u003e15 (29.4%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 387px;\"\u003e\n \u003cp\u003eFibroadenoma of breast\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 181px;\"\u003e\n \u003cp\u003e7 (13.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 387px;\"\u003e\n \u003cp\u003eAdenosis of breast\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 181px;\"\u003e\n \u003cp\u003e5 (9.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 387px;\"\u003e\n \u003cp\u003eIntraductal papilloma\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 181px;\"\u003e\n \u003cp\u003e3 (5.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"4\" valign=\"top\" style=\"width: 568px;\"\u003e\n \u003cp\u003eTable 2 \u0026nbsp;Comparison of \u003csup\u003e18\u003c/sup\u003eF-FAPI-04 uptake between early imaging and conventional imaging\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 183px;\"\u003e\n \u003cp\u003eVariables\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 169px;\"\u003e\n \u003cp\u003eEarly imaging\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 152px;\"\u003e\n \u003cp\u003eConventional imaging\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 63px;\"\u003e\n \u003cp\u003eP\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 183px;\"\u003e\n \u003cp\u003eSUVmax of all lesions\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 169px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 152px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 63px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 183px;\"\u003e\n \u003cp\u003eMean (SD)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 169px;\"\u003e\n \u003cp\u003e7.63 \u0026plusmn; 5.55\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 152px;\"\u003e\n \u003cp\u003e8.25 \u0026plusmn; 5.85\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 63px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 183px;\"\u003e\n \u003cp\u003eMedian (IQR)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 169px;\"\u003e\n \u003cp\u003e6.66(2.97, 11.34)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 152px;\"\u003e\n \u003cp\u003e7.93(2.52, 12.47)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 63px;\"\u003e\n \u003cp\u003e0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 183px;\"\u003e\n \u003cp\u003eSUVmax of BC\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 169px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 152px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 63px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 183px;\"\u003e\n \u003cp\u003eMean (SD)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 169px;\"\u003e\n \u003cp\u003e10.19 \u0026plusmn; 4.55\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 152px;\"\u003e\n \u003cp\u003e10.99 \u0026plusmn; 4.70\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 63px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 183px;\"\u003e\n \u003cp\u003eMedian (IQR)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 169px;\"\u003e\n \u003cp\u003e9.02(6.57, 13.04)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 152px;\"\u003e\n \u003cp\u003e10.21(7.62, 13.01)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 63px;\"\u003e\n \u003cp\u003e0.003\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 183px;\"\u003e\n \u003cp\u003eSUVmax of BBL\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 169px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 152px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 63px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 183px;\"\u003e\n \u003cp\u003eMean (SD)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 169px;\"\u003e\n \u003cp\u003e1.49 \u0026plusmn; 1.01\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 152px;\"\u003e\n \u003cp\u003e1.65 \u0026plusmn; 0.93\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 63px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 183px;\"\u003e\n \u003cp\u003eMedian (IQR)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 169px;\"\u003e\n \u003cp\u003e1.23(0.71, 1.92)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 152px;\"\u003e\n \u003cp\u003e1.62(1.01, 1.94)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 63px;\"\u003e\n \u003cp\u003e0.135\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"4\" valign=\"top\" style=\"width: 568px;\"\u003e\n \u003cp\u003eTable 3 Background and lesion-to-background ratios\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 181px;\"\u003e\n \u003cp\u003eVariables\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 172px;\"\u003e\n \u003cp\u003eEarly imaging\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 152px;\"\u003e\n \u003cp\u003eConventional imaging\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 63px;\"\u003e\n \u003cp\u003eP\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 181px;\"\u003e\n \u003cp\u003eSUVmean of breast\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 172px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 152px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 63px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 181px;\"\u003e\n \u003cp\u003eMean (SD)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 172px;\"\u003e\n \u003cp\u003e0.89 \u0026plusmn; 0.65\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 152px;\"\u003e\n \u003cp\u003e1.04 \u0026plusmn; 0.87\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 63px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 181px;\"\u003e\n \u003cp\u003eMedian (IQR)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 172px;\"\u003e\n \u003cp\u003e0.69(0.44, 1.14)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 152px;\"\u003e\n \u003cp\u003e0.87(0.58, 1.48)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 63px;\"\u003e\n \u003cp\u003e0.002\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 181px;\"\u003e\n \u003cp\u003eLBR of all lesions\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 172px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 152px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 63px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 181px;\"\u003e\n \u003cp\u003eMean (SD)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 172px;\"\u003e\n \u003cp\u003e13.50 \u0026plusmn; 16.55\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 152px;\"\u003e\n \u003cp\u003e11.07 \u0026plusmn; 11.85\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 63px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 181px;\"\u003e\n \u003cp\u003eMedian (IQR)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 172px;\"\u003e\n \u003cp\u003e7.05(2.91, 14.97)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 152px;\"\u003e\n \u003cp\u003e5.77(3.21, 14.62)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 63px;\"\u003e\n \u003cp\u003e0.456\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 181px;\"\u003e\n \u003cp\u003eLBRc of BC\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 172px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 152px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 63px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 181px;\"\u003e\n \u003cp\u003eMean (SD)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 172px;\"\u003e\n \u003cp\u003e18.01 \u0026plusmn; 17.84\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 152px;\"\u003e\n \u003cp\u003e14.71 \u0026plusmn; 12.40\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 63px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 181px;\"\u003e\n \u003cp\u003eMedian (IQR)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 172px;\"\u003e\n \u003cp\u003e11.63(6.11, 21.05)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 152px;\"\u003e\n \u003cp\u003e11.72(5.16, 19.63)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 63px;\"\u003e\n \u003cp\u003e0.396\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 181px;\"\u003e\n \u003cp\u003eLBRc of BBL\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 172px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 152px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 63px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 181px;\"\u003e\n \u003cp\u003eMean (SD)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 172px;\"\u003e\n \u003cp\u003e2.67 \u0026plusmn; 2.14\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 152px;\"\u003e\n \u003cp\u003e2.34 \u0026plusmn; 1.21\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 63px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 181px;\"\u003e\n \u003cp\u003eMedian (IQR)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 172px;\"\u003e\n \u003cp\u003e1.87(1.51, 2.69)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 152px;\"\u003e\n \u003cp\u003e2.62(1.40, 3.21)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 63px;\"\u003e\n \u003cp\u003e0.89\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"730\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"9\" valign=\"top\" style=\"width: 730px;\"\u003e\n \u003cp\u003eTable 4 \u0026nbsp;Diagnostic performance of semi-quantitative parameters\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"2\" style=\"width: 64px;\"\u003e\n \u003cp\u003eVariables\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\" style=\"width: 109px;\"\u003e\n \u003cp\u003eTime phase\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\" style=\"width: 93px;\"\u003e\n \u003cp\u003eCutt off\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\" style=\"width: 121px;\"\u003e\n \u003cp\u003eAUC(95% CI)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\" style=\"width: 93px;\"\u003e\n \u003cp\u003eSensitivity(%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\" style=\"width: 92px;\"\u003e\n \u003cp\u003eSpecificity(%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\" style=\"width: 73px;\"\u003e\n \u003cp\u003eYouden\u0026rsquo;s Index\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 85px;\"\u003e\n \u003cp\u003eDeLong\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 41px;\"\u003e\n \u003cp\u003ez\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 44px;\"\u003e\n \u003cp\u003ep\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"2\" style=\"width: 64px;\"\u003e\n \u003cp\u003eSUVmax\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 109px;\"\u003e\n \u003cp\u003eEarly\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 93px;\"\u003e\n \u003cp\u003e3.62\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 121px;\"\u003e\n \u003cp\u003e1(1-1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 93px;\"\u003e\n \u003cp\u003e100%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 92px;\"\u003e\n \u003cp\u003e100%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 73px;\"\u003e\n \u003cp\u003e1.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\" style=\"width: 41px;\"\u003e\n \u003cp\u003e0.71\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\" style=\"width: 44px;\"\u003e\n \u003cp\u003e0.48\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 109px;\"\u003e\n \u003cp\u003eConventional\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 93px;\"\u003e\n \u003cp\u003e4.12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 121px;\"\u003e\n \u003cp\u003e0.99(0.99-1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 93px;\"\u003e\n \u003cp\u003e97.2%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 92px;\"\u003e\n \u003cp\u003e100%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 73px;\"\u003e\n \u003cp\u003e0.97\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"2\" style=\"width: 64px;\"\u003e\n \u003cp\u003eLBR\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 109px;\"\u003e\n \u003cp\u003eEarly\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 93px;\"\u003e\n \u003cp\u003e4.42\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 121px;\"\u003e\n \u003cp\u003e0.93(0.86-1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 93px;\"\u003e\n \u003cp\u003e86.1%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 92px;\"\u003e\n \u003cp\u003e86.7%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 73px;\"\u003e\n \u003cp\u003e0.73\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\" style=\"width: 41px;\"\u003e\n \u003cp\u003e1.14\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\" style=\"width: 44px;\"\u003e\n \u003cp\u003e0.25\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 109px;\"\u003e\n \u003cp\u003eConventional\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 93px;\"\u003e\n \u003cp\u003e4.34\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 121px;\"\u003e\n \u003cp\u003e0.97(0.93-1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 93px;\"\u003e\n \u003cp\u003e88.9%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 92px;\"\u003e\n \u003cp\u003e100%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 73px;\"\u003e\n \u003cp\u003e0.89\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"FAPI, PET/CT, Breast cancer, Early imaging, SUVmax, LBR","lastPublishedDoi":"10.21203/rs.3.rs-7636266/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7636266/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003csup\u003e18\u003c/sup\u003eFluorine (\u003csup\u003e18\u003c/sup\u003eF) labeled inhibitors of fibroblast activation protein(\u003csup\u003e18\u003c/sup\u003eF-FAPI) PET/CT is an emerging molecular imaging technique suitable for patients with breast cancers(BC). However, some patients may not tolerate the long waiting time after injection, making it crucial to assess whether early imaging can provide sufficient clinical diagnostic information. In this prospective study, 40 patients with suspected BC underwent dual-phase \u003csup\u003e18\u003c/sup\u003eF-FAPI PET/CT at ~10 minutes (early) and ~60 minutes (conventional) post-injection. The diagnostic performance of both protocols was compared in differentiating benign from malignant lesions. A total of 51 breast lesions were detected, and SUVmax and lesion-to-background ratio (LBR) were obtained by outlining ROIs. After the PET/CT scan, all lesions underwent tissue biopsy, with 36 being BC and 15 \u003cstrong\u003ebenign breast lesions (BBL)\u003c/strong\u003e. The results showed a significant difference in SUVmax between early and conventional imaging (p=0.001), but no significant difference in LBR (p=0.456). The FAPI uptake in the BC group was significantly higher than in the BBL group. The cutoff values for SUVmax were 3.62 for early imaging and 4.12 for conventional imaging, while the cutoff values for LBR were 4.42 for early imaging and 4.34 for conventional imaging. At the optimal cutoff values, early imaging with SUVmax achieved the highest diagnostic performance, with an AUC of 1.00, and both sensitivity and specificity of 100%. The AUC for LBR was 0.93, with a sensitivity of 86.1% and specificity of 86.7%. No significant difference in diagnostic performance was found between early and conventional imaging (DeLong test; SUVmax p=0.48 and LBR p=0.25). Our findings indicate that early \u003csup\u003e18\u003c/sup\u003eF-FAPI PET/CT imaging offers diagnostic accuracy comparable to conventional imaging while significantly reducing acquisition time, supporting its potential as a practical alternative in clinical practice.\u003c/p\u003e","manuscriptTitle":"Early 18F-FAPI PET/CT Imaging for Breast Cancer Diagnosis: A Prospective Comparison with Conventional Imaging Protocols","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-10-01 10:05:14","doi":"10.21203/rs.3.rs-7636266/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-10-07T08:58:52+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-10-06T11:19:42+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-09-28T13:24:37+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"131002222214471179119314306274173589966","date":"2025-09-25T16:27:14+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-09-21T11:42:18+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"269201225190257206961438854897098904978","date":"2025-09-21T09:02:21+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"211724908245217873852276245007058623735","date":"2025-09-20T18:56:23+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-09-20T16:10:44+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2025-09-19T11:25:57+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-09-18T11:47:57+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-09-18T03:04:46+00:00","index":"","fulltext":""},{"type":"submitted","content":"Scientific Reports","date":"2025-09-17T05:56:19+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"cfb655ff-1e8a-417c-a00e-a49e0837de9d","owner":[],"postedDate":"October 1st, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[{"id":55619444,"name":"Biological sciences/Cancer"},{"id":55619445,"name":"Health sciences/Medical research"},{"id":55619446,"name":"Health sciences/Oncology"}],"tags":[],"updatedAt":"2025-12-15T16:00:22+00:00","versionOfRecord":{"articleIdentity":"rs-7636266","link":"https://doi.org/10.1038/s41598-025-28097-0","journal":{"identity":"scientific-reports","isVorOnly":false,"title":"Scientific Reports"},"publishedOn":"2025-12-08 15:57:04","publishedOnDateReadable":"December 8th, 2025"},"versionCreatedAt":"2025-10-01 10:05:14","video":"","vorDoi":"10.1038/s41598-025-28097-0","vorDoiUrl":"https://doi.org/10.1038/s41598-025-28097-0","workflowStages":[]},"version":"v1","identity":"rs-7636266","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7636266","identity":"rs-7636266","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}