image: Figure 1. Top image displays patient assessed for acute renal failure following third Lutathera administration where 3D dosimetry showed an average-per-administration kidney absorbed dose of 5 Gray, with total course of therapy being well under toxicity limits. Bottom image displays a patient’s absorbed dose to the colon after his first dose of Pluvicto where 3D dosimetry was used to confirm transient bowel obstruction leading to treatment management.
Credit: Images created by Taylor Gillespie et al., University of Tennessee Graduate School of Medicine, Molecular Imaging and Theranostic Research Program, Knoxville, TN.
NEW ORLEANS—Post-therapy imaging and dosimetry significantly enhance patient management, empowering clinicians to make more informed, personalized decisions in radiopharmaceutical therapy. A series of case studies presented at the Society of Nuclear Medicine and Molecular Imaging 2025 Annual Meeting highlights how this approach improves patient outcomes, guides clinical decision-making, and drives meaningful changes in clinical practice.
Radiopharmaceutical therapy is rapidly gaining momentum in the United States, fueled by recent FDA approvals that expand access to targeted cancer treatments. However, post-therapy imaging and dosimetry—long considered essential in external beam radiation oncology—have yet to become standard practice in this growing field.
“Most institutions only look at imaging and dosimetry to adjust a patient’s dose rather than to assess the impact it can have on overall care,” said Taylor Gillespie, nuclear medicine clinical research leader at the University of Tennessee Medical Center in Knoxville, Tennessee. “In our program, we perform post-therapy imaging and dosimetry for every patient receiving lutetium-based therapies and have seen a significant enhancement in patient management.”
The study analyzed case reports from patients treated with lutetium-based therapies at the University of Tennessee Medical Center. Each patient received a standard dose of 177Lu-DOTATATE or 177Lu-PSMA, followed by two post-treatment scans—one shortly after therapy and another several days later—to monitor how the treatment distributed throughout the body. Using advanced software, technologists and physicists measured how long the radiation remained in different organs and calculated the radiation dose each organ received.
Case studies illustrated how dosimetry played a vital role in ensuring patient safety and tailoring treatments in lutetium-based therapies. It helped identify causes of complications, such as non-compliance with hydration guidelines, radiation exposure to sensitive organs, and unexpected disease findings. Dosimetry guided clinical decisions to continue, modify, or stop therapy, prompted changes in imaging protocols, improved symptom management, and enhanced radiation safety measures—ultimately optimizing treatment outcomes and protecting patients.
“These cases show that post-therapy imaging and dosimetry— instead of just following generic rules or assumptions—can make treatment safer and personalized,” Gillespie noted. “If more hospitals conduct post-therapy imaging and dosimetry, it could lead to national guidelines that help patients everywhere, even in places without specialized staff.”
According to Gillespie, these findings have the potential to drive meaningful change in nuclear medicine, particularly as the field advances in theranostics, shifting from solely diagnosing disease to actively guiding patient care. This approach not only strengthens nuclear medicine’s role in treatment planning but also creates new professional growth opportunities, positioning the specialty as integral to both diagnosis and therapeutic decision-making.
Abstract 25140. “Impact of Post-Therapy Imaging and Dosimetry on Patient Management in Radionuclide Therapy: A Case Study Review,” Taylor Gillespie, Amy Swinson, Yitong Fu, Brett Miller, and Dustin Osborne, University of Tennessee Medical Center, Knoxville, Tennssee.
Link to Abstract
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All 2025 SNMMI Annual Meeting abstracts can be found online.
About the Society of Nuclear Medicine and Molecular Imaging
The Society of Nuclear Medicine and Molecular Imaging (SNMMI) is an international scientific and medical organization dedicated to advancing nuclear medicine, molecular imaging, and theranostics—precision medicine that allows diagnosis and treatment to be tailored to individual patients in order to achieve the best possible outcomes.
SNMMI’s members set the standard for molecular imaging and nuclear medicine practice by creating guidelines, sharing information through journals and meetings and leading advocacy on key issues that affect molecular imaging and therapy research and practice. For more information, visit www.snmmi.org.
Journal
Journal of Nuclear Medicine
Article Title
Impact of Post-Therapy Imaging and Dosimetry on Patient Management in Radionuclide Therapy: A Case Study Review