Abstract
The variation of permanent prostate brachytherapy dosimetry as a function of seed localization uncertainty was investigated for I-125 implants with seed activities commonly employed in contemporary practice. Post-implant imaging and radiation dosimetry data from nine patients who underwent permanent prostate brachytherapy served as the source of clinical data for this simulation study. Gaussian noise with standard deviations ranging from 0.5 to 10 mm was applied to the seed coordinates for each patient dataset and 1000 simulations were performed at each noise level. Dose parameters, including D90, were computed for each case and compared with the actual dosimetry data. A total of 81 000 complete sets of post-brachytherapy dose volume statistics were computed. The results demonstrated that less than 5% deviation of prostate D90 can be expected when the seed localization uncertainty is 2 mm, whereas a seed localization uncertainty of 10 mm yielded an average decrease in D90 of 33 Gy. The mean normalized decrement in the prostate V100 was 10% at 5 mm uncertainty. Implants with greater seed number and larger prostate volume correlated with less sensitivity of D90 and V100 to seed localization uncertainty. Estimated target volume dose parameters tended to decrease with increasing seed localization uncertainty. The bladder V100 varied more significantly both in mean and standard deviation as compared to the urethra V100. A larger number of implanted seeds also correlated to less sensitivity of the bladder V100 to seed localization uncertainty. In contrast, the deviation of urethra V100 did not correlate with the number of implanted seeds or prostate volume.
| Original language | English (US) |
|---|---|
| Article number | 012 |
| Pages (from-to) | 3105-3119 |
| Number of pages | 15 |
| Journal | Physics in Medicine and Biology |
| Volume | 52 |
| Issue number | 11 |
| DOIs | |
| State | Published - Jun 7 2007 |
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ASJC Scopus subject areas
- Biomedical Engineering
- Physics and Astronomy (miscellaneous)
- Radiology Nuclear Medicine and imaging
- Radiological and Ultrasound Technology
Cite this
Dosimetry accuracy as a function of seed localization uncertainty in permanent prostate brachytherapy : Increased seed number correlates with less variability in prostate dosimetry. / Su, Yi; Davis, Brian J.; Furutani, Keith M.; Herman, Michael G.; Robb, Richard A.
In: Physics in Medicine and Biology, Vol. 52, No. 11, 012, 07.06.2007, p. 3105-3119.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Dosimetry accuracy as a function of seed localization uncertainty in permanent prostate brachytherapy
T2 - Increased seed number correlates with less variability in prostate dosimetry
AU - Su, Yi
AU - Davis, Brian J.
AU - Furutani, Keith M.
AU - Herman, Michael G.
AU - Robb, Richard A.
PY - 2007/6/7
Y1 - 2007/6/7
N2 - The variation of permanent prostate brachytherapy dosimetry as a function of seed localization uncertainty was investigated for I-125 implants with seed activities commonly employed in contemporary practice. Post-implant imaging and radiation dosimetry data from nine patients who underwent permanent prostate brachytherapy served as the source of clinical data for this simulation study. Gaussian noise with standard deviations ranging from 0.5 to 10 mm was applied to the seed coordinates for each patient dataset and 1000 simulations were performed at each noise level. Dose parameters, including D90, were computed for each case and compared with the actual dosimetry data. A total of 81 000 complete sets of post-brachytherapy dose volume statistics were computed. The results demonstrated that less than 5% deviation of prostate D90 can be expected when the seed localization uncertainty is 2 mm, whereas a seed localization uncertainty of 10 mm yielded an average decrease in D90 of 33 Gy. The mean normalized decrement in the prostate V100 was 10% at 5 mm uncertainty. Implants with greater seed number and larger prostate volume correlated with less sensitivity of D90 and V100 to seed localization uncertainty. Estimated target volume dose parameters tended to decrease with increasing seed localization uncertainty. The bladder V100 varied more significantly both in mean and standard deviation as compared to the urethra V100. A larger number of implanted seeds also correlated to less sensitivity of the bladder V100 to seed localization uncertainty. In contrast, the deviation of urethra V100 did not correlate with the number of implanted seeds or prostate volume.
AB - The variation of permanent prostate brachytherapy dosimetry as a function of seed localization uncertainty was investigated for I-125 implants with seed activities commonly employed in contemporary practice. Post-implant imaging and radiation dosimetry data from nine patients who underwent permanent prostate brachytherapy served as the source of clinical data for this simulation study. Gaussian noise with standard deviations ranging from 0.5 to 10 mm was applied to the seed coordinates for each patient dataset and 1000 simulations were performed at each noise level. Dose parameters, including D90, were computed for each case and compared with the actual dosimetry data. A total of 81 000 complete sets of post-brachytherapy dose volume statistics were computed. The results demonstrated that less than 5% deviation of prostate D90 can be expected when the seed localization uncertainty is 2 mm, whereas a seed localization uncertainty of 10 mm yielded an average decrease in D90 of 33 Gy. The mean normalized decrement in the prostate V100 was 10% at 5 mm uncertainty. Implants with greater seed number and larger prostate volume correlated with less sensitivity of D90 and V100 to seed localization uncertainty. Estimated target volume dose parameters tended to decrease with increasing seed localization uncertainty. The bladder V100 varied more significantly both in mean and standard deviation as compared to the urethra V100. A larger number of implanted seeds also correlated to less sensitivity of the bladder V100 to seed localization uncertainty. In contrast, the deviation of urethra V100 did not correlate with the number of implanted seeds or prostate volume.
UR - http://www.scopus.com/inward/record.url?scp=34249071654&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=34249071654&partnerID=8YFLogxK
U2 - 10.1088/0031-9155/52/11/012
DO - 10.1088/0031-9155/52/11/012
M3 - Article
C2 - 17505092
AN - SCOPUS:34249071654
VL - 52
SP - 3105
EP - 3119
JO - Physics in Medicine and Biology
JF - Physics in Medicine and Biology
SN - 0031-9155
IS - 11
M1 - 012
ER -