Dose-Activity Relationship in [131I]NaI Therapy for Differentiated Thyroid Carcinoma

Dose-Activity Relationship in [131I]NaI Therapy for Differentiated Thyroid Carcinoma | 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 Research Article Dose-Activity Relationship in [ 131 I]NaI Therapy for Differentiated Thyroid Carcinoma Álvaro Luján-Expósito This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7231810/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Background : Current clinical practice guidelines often advocate for fixed [ 131 I]NaI activity prescriptions based on patient diagnosis and risk stratification, frequently disregarding individual patient-specific radioiodine kinetics. This approach may result in substantial variability in the absorbed dose to target tissues and organs at risk. Purpose : This study aimed to analyze the relationship between the absorbed dose in target organs (thyroid remnants) and organs at risk (red bone marrow) with potential explanatory variables, particularly the administered [ 131 I]NaI activity. Methods : A cross-sectional pilot study was conducted involving DTC patients treated with [ 131 I]NaI at the Hospital Clínico Universitario Virgen de la Arrixaca (HCUVA) in Murcia between September 2024 and May 2025. Baseline patient data and other treatment-specific data available in their clinical records were collected to calculate the absorbed dose according to the existing protocol for this purpose at the center. Results : No significant correlation was observed between the absorbed dose in thyroid remnants and the administered activity. Conversely, a significant association was found between the absorbed dose in the red bone marrow and the administered activity. Conclusion : Administering [ 131 I]NaI without individualizing treatment based on radiopharmaceutical kinetics and patient-specific tumor burden does not result in proportionally higher absorbed doses in thyroid remnants or enhanced therapeutic efficacy. Instead, it significantly increases the absorbed dose to organs at risk, such as the red bone marrow. Nuclear Medicine & Medical Imaging Medical Physics Differentiated Thyroid Carcinoma Red bone marrow Thyroid remnant ablation Absorbed dose Full Text Additional Declarations The authors declare no competing interests. Cite Share Download PDF Status: Posted Version 1 posted 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. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7231810","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":491836139,"identity":"70b4958e-ca1d-4a58-8c0b-3f16cb006c86","order_by":0,"name":"Álvaro Luján-Expósito","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA40lEQVRIiWNgGAWjYDACdgglw8BwgIHhA1FamCEUD0gL4wwStQDZPMTo4G/mMfxcUcHAY3Dw8LPHNjV2+boNzIfxOlDiMI+x5JkzQC0Hjpkb5xxLttx2gC1NAq81h9kSJBvbQFoOmEnnNjAbmB3gMcOrQ/4wW/JPiJbj36QtG+qBWvg/43WYwWHmY1BbzphJMzYcBtnCgNdhhkAtlg1nJHgkD5wpk+w5dtzA7DCbGV4tcscbm282VNjI8d04vk3iR021gdnx5sfERCnQWIkDUDYzEeohgL+BaKWjYBSMglEwwgAAI9FFb6zgnRoAAAAASUVORK5CYII=","orcid":"https://orcid.org/0009-0000-3155-4602","institution":"Hospital Clínico Universitario Virgen de la Arrixaca","correspondingAuthor":true,"prefix":"","firstName":"Álvaro","middleName":"","lastName":"Luján-Expósito","suffix":""}],"badges":[],"createdAt":"2025-07-28 08:57:45","currentVersionCode":1,"declarations":{"humanSubjects":true,"vertebrateSubjects":false,"conflictsOfInterestStatement":false,"humanSubjectEthicalGuidelines":true,"humanSubjectConsent":true,"humanSubjectClinicalTrial":false,"humanSubjectCaseReport":true,"vertebrateSubjectEthicalGuidelines":false},"doi":"10.21203/rs.3.rs-7231810/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7231810/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":87786746,"identity":"61926c0b-58d5-4269-8bf9-3d031a8437e4","added_by":"auto","created_at":"2025-07-29 04:10:08","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":254631,"visible":true,"origin":"","legend":"","description":"","filename":"Manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7231810/v1_covered_0e608153-7fa6-44fc-8e15-70b1a1203263.pdf"}],"financialInterests":"The authors declare no competing interests.","formattedTitle":"\u003cp\u003eDose-Activity Relationship in [\u003csup\u003e131\u003c/sup\u003eI]NaI Therapy for Differentiated Thyroid Carcinoma\u003c/p\u003e","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"highlight":"","institution":"Hospital Universitario Virgen de la Arrixaca","isAcceptedByJournal":false,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":true,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Differentiated Thyroid Carcinoma, Red bone marrow, Thyroid remnant ablation, Absorbed dose","lastPublishedDoi":"10.21203/rs.3.rs-7231810/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7231810/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eBackground\u003c/strong\u003e: Current clinical practice guidelines often advocate for fixed [\u003csup\u003e131\u003c/sup\u003eI]NaI activity prescriptions based on patient diagnosis and risk stratification, frequently disregarding individual patient-specific radioiodine kinetics. This approach may result in substantial variability in the absorbed dose to target tissues and organs at risk.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003ePurpose\u003c/strong\u003e: This study aimed to analyze the relationship between the absorbed dose in target organs (thyroid remnants) and organs at risk (red bone marrow) with potential explanatory variables, particularly the administered [\u003csup\u003e131\u003c/sup\u003eI]NaI activity.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethods\u003c/strong\u003e: A cross-sectional pilot study was conducted involving DTC patients treated with [\u003csup\u003e131\u003c/sup\u003eI]NaI at the Hospital Clínico Universitario Virgen de la Arrixaca \u0026nbsp;(HCUVA) in Murcia between September 2024 and May 2025. Baseline patient data and other treatment-specific data available in their clinical records were collected to calculate the absorbed dose according to the existing protocol for this purpose at the center.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults\u003c/strong\u003e: No significant correlation was observed between the absorbed dose in thyroid remnants and the administered activity. Conversely, a significant association was found between the absorbed dose in the red bone marrow and the administered activity.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusion\u003c/strong\u003e: Administering [\u003csup\u003e131\u003c/sup\u003eI]NaI without individualizing treatment based on radiopharmaceutical kinetics and patient-specific tumor burden does not result in proportionally higher absorbed doses in thyroid remnants or enhanced therapeutic efficacy. 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