Author: John P. Aris, Wesley E. Bolch, Chansoo Choi, Carlos G. Colon-Ortiz, Robert Joseph Dawson, Abdul-Vehab Dozic, Amy M. Geyer, Harald Paganetti, Shreya P. Pathak, Julia D. Withrow 👨🔬
Affiliation: St. Luke's Health System, Massachusetts General Hospital, University of Florida 🌍
Purpose: The goal of this study was to enhance the accuracy of renal dosimetry in radiopharmaceutical therapy (RPT) by developing a more detailed and precise kidney model. In RPT, accurate dose estimation is critical for optimizing therapeutic efficacy while minimizing the risk of renal toxicity. Current dosimetric models often lack sufficient anatomical and functional details, leading to suboptimal dose calculations. Therefore, this study aims to refine renal dosimetry by accounting for the kidney's complex structure and physiology to improve the precision of radiation dose estimations for individual patients undergoing RPT.
Methods: A multiregion kidney model was developed, integrating detailed anatomical features of the kidney, such as the renal capsule, medullary pyramids, cortical regions, and internal pelvic structures. Monte Carlo simulations were conducted using the Particle and Heavy Ion Transport code System (PHITS), which allowed for highly detailed modeling of radiation interactions within the kidney. The study utilized updated specific absorbed fractions (SAF) and S value calculations based on the latest guidelines from the International Commission on Radiological Protection (ICRP). Various radiopharmaceuticals were modeled, including photon, beta, and Auger-emitting radionuclides, which are commonly used in RPT.
Results: The refined kidney model showed significant improvements over previous models in terms of absorbed dose accuracy. By considering the nonuniform distribution of radioactivity within the kidney, the model produced more precise estimates of dose deposition. The updated S values and absorbed fractions enabled a better understanding of how different radiopharmaceuticals affect kidney tissues at a cellular level, leading to more reliable dosimetry for both targeted and untargeted therapies.
Conclusion: This study provides a more accurate and detailed approach to renal dosimetry, with potential applications in patient-specific dosimetry for radiopharmaceutical therapies. The refined model and updated dosimetry data contribute to safer and more effective treatment strategies, reducing renal toxicity and optimizing therapeutic outcomes in RPT.