RT Journal Article
SR Electronic
T1 Feasibility of Single-Time-Point Dosimetry for Radiopharmaceutical Therapies
JF Journal of Nuclear Medicine
JO J Nucl Med
FD Society of Nuclear Medicine
SP 1006
OP 1011
DO 10.2967/jnumed.120.254656
VO 62
IS 7
A1 Xinchi Hou
A1 Julia Brosch
A1 Carlos Uribe
A1 Alessandro Desy
A1 Guido Böning
A1 Jean-Mathieu Beauregard
A1 Anna Celler
A1 Arman Rahmim
YR 2021
UL http://jnm.snmjournals.org/content/62/7/1006.abstract
AB Because of challenges in performing routine personalized dosimetry in radiopharmaceutical therapies, interest in single-time-point (STP) dosimetry, particularly using only a single SPECT scan, is on the rise. Meanwhile, there are questions about the reliability of STP dosimetry, with limited independent validations. In the present work, we analyzed 2 STP dosimetry methods and evaluated dose errors for several radiopharmaceuticals based on effective half-life distributions. Methods: We first challenged the common assumption that radiopharmaceutical effective half-lives across the population are gaussian-distributed (i.e., follow a normal distribution). Then, dose accuracy was estimated using 2 STP dosimetry methods for a wide range of potential post injection (p.i.) scan time points for different radiopharmaceuticals applied to neuroendocrine tumors and prostate cancer. The accuracy and limitations of each of the STP methods were discussed. Results: A lognormal distribution was more appropriate for capturing effective half-life distributions. The STP framework was promising for dosimetry of 177Lu-DOTATATE and for kidney dosimetry of different radiopharmaceuticals (errors < 30%). Meanwhile, for some radiopharmaceuticals, STP accuracy was compromised (e.g., in bone marrow and tumors for 177-labeled prostate-specific membrane antigen [PSMA])). The optimal SPECT scanning time for 177Lu-DOTATATE was approximately 72 h p.i., whereas 48 h p.i. was better for 177Lu-PSMA. Conclusion: Simplified STP dosimetry methods may compromise the accuracy of dose estimates, with some exceptions, such as for 177Lu-DOTATATE and for kidney dosimetry in different radiopharmaceuticals. Simplified personalized dosimetry in the clinic continues to be challenging. On the basis of our results, we make suggestions and recommendations for improved personalized dosimetry using simplified imaging schemes.