International journal of radiation oncology, biology, physics · 2025
177Lu-PSMA-617 Single-Photon Emission Computed Tomography/Computed Tomography Dosimetry and Radiobiological Models Demonstrate Decreasing Tumor-to-Kidney Dose Ratio With Successive Cycles.
СтатьяПоддержка NIH: внешняя программаПоддержка исследования: вне правительства СШАНазвание и аннотация: Перевод в очереди
Обработка статьи · этапы, ошибки и управление
Загрузка состояния…
Ошибки и ограничения
История · было → стало
Состояние обновляется каждые 5 секунд, пока блок открыт. Процент показывается только там, где известен объём работы. Пауза останавливает продолжение этапа; текущий запрос к источнику может завершиться.
Fitzpatrick Kellen J, Mikell Justin K, Roseland Molly E, Niedbala Jeremy, Suresh Krithika, Peterson Avery B, Viglianti Benjamin L, Wong Ka Kit, Frey Kirk A, Dewaraja Yuni K
Аннотация
PURPOSE: Dosimetry studies following 177Lu-PSMA-617 radioligand therapy (RLT) for metastatic castration-resistant prostate cancer have focused primarily on absorbed dose (AD). Biologically effective dose (BED) and equieffective dose in 2 Gray fractions (EQD2) further account for dose delivery rate, tissue repair rate, and radiosensitivity. Our aims were to investigate cycle-to-cycle changes in tumor and organ AD, BED, and EQD2 and tumor-to-kidney dose ratio (TKR) for the given dose metric.
METHODS AND MATERIALS: Serial single-photon emission computed tomography/computed tomography imaging was performed after cycle 1 or cycles 1 and 2 of 177Lu-PSMA-617 RLT. BED and EQD2 were calculated using 2 sets of tumor radiobiological parameters: α/βtumor = 3 Gy, Trep,tumor = 0.27 hours, proposed for prostate cancer, and α/βtumor = 10 Gy, Trep,tumor = 1.5 hours, commonly used for other tumor types. Kidney parameters were α/βkidney = 2.6 Gy and Trep,kidney = 2.8 hours. TKR was compared for patients with imaging after cycles 1 and 2. The relationship between cycle 1 whole-body tumor volume (WBTV) dose metrics and change in prostate-specific antigen (PSA) level was also investigated.
RESULTS: Ninety-one tumors were segmented in 20 patients with cycle 1 imaging; 10 also received imaging after cycle 2. Median (range) cycle 1 ADs were 17.7 (0.5-155.9) Gy to the tumor and 2.6 (0.5-10.0) Gy to the kidney. Tumor AD decreased from cycle 1 to 2, whereas organ AD remained constant. Median TKRAD decreased from 6.6 to 3.1 while TKREQD2 (α/βtumor = 10 Gy) decreased from 9.0 to 4.3. For tumors receiving higher AD, the decrease in TKR with cycle was up to 30% greater when calculated with radiobiological models than with AD. Furthermore, a significant association between early PSA response and cycle 1 WBTV dose metrics was demonstrated (Spearman ρ = 0.63, P = .005).
CONCLUSIONS: A strong dose-response relationship was seen between cycle 1 WBTV dose metrics and a decrease in PSA. Radiobiological models can substantially impact the TKR and the cycle-to-cycle change in TKR and should be considered when investigating novel 177Lu-PSMA-617 RLT dosing schemas.
METHODS AND MATERIALS: Serial single-photon emission computed tomography/computed tomography imaging was performed after cycle 1 or cycles 1 and 2 of 177Lu-PSMA-617 RLT. BED and EQD2 were calculated using 2 sets of tumor radiobiological parameters: α/βtumor = 3 Gy, Trep,tumor = 0.27 hours, proposed for prostate cancer, and α/βtumor = 10 Gy, Trep,tumor = 1.5 hours, commonly used for other tumor types. Kidney parameters were α/βkidney = 2.6 Gy and Trep,kidney = 2.8 hours. TKR was compared for patients with imaging after cycles 1 and 2. The relationship between cycle 1 whole-body tumor volume (WBTV) dose metrics and change in prostate-specific antigen (PSA) level was also investigated.
RESULTS: Ninety-one tumors were segmented in 20 patients with cycle 1 imaging; 10 also received imaging after cycle 2. Median (range) cycle 1 ADs were 17.7 (0.5-155.9) Gy to the tumor and 2.6 (0.5-10.0) Gy to the kidney. Tumor AD decreased from cycle 1 to 2, whereas organ AD remained constant. Median TKRAD decreased from 6.6 to 3.1 while TKREQD2 (α/βtumor = 10 Gy) decreased from 9.0 to 4.3. For tumors receiving higher AD, the decrease in TKR with cycle was up to 30% greater when calculated with radiobiological models than with AD. Furthermore, a significant association between early PSA response and cycle 1 WBTV dose metrics was demonstrated (Spearman ρ = 0.63, P = .005).
CONCLUSIONS: A strong dose-response relationship was seen between cycle 1 WBTV dose metrics and a decrease in PSA. Radiobiological models can substantially impact the TKR and the cycle-to-cycle change in TKR and should be considered when investigating novel 177Lu-PSMA-617 RLT dosing schemas.