TY - JOUR
T1 - Postprostatectomy target-normal structure overlap volume differences using computed tomography and radioimmunoscintigraphy images for radiotherapy treatment planning
AU - Su, Andy
AU - Blend, Michael J.
AU - Spelbring, Danny
AU - Hamilton, Russell J.
AU - Jani, Ashesh B.
PY - 2006/3
Y1 - 2006/3
N2 - PURPOSE: The purpose of this study was to analyze regions of uptake in normal structures on postprostatectomy radioimmunoscintigraphy (RIS) images by evaluating differences in the overlap volumes of prostate fossa clinical target volume (CTV) and planning target volume (PTV) using correlative computed tomography (CT) images. MATERIALS AND METHODS: The electronic records of 13 patients who received external beam radiotherapy postprostatectomy and who underwent a vessel-based RIS/CT registration were reviewed. For each patient, the RIS-defined CTV (CTVRIS) was compared (in terms of the overlap volume with the surrounding bladder, rectum, pubic symphysis, and penile bulb) with the CT-defined CTVpre before this registration and also with CTVpost (the final target volume used for treatment). Similar analyses were done for PTVRIS, PTVpre, and PTVpost defined in each case to be the corresponding CTV + 1-cm margin. RESULTS: CTVRIS overlapped significantly more with the bladder, rectum, and symphysis, but not with the penile bulb, than did either the CTVpre or CTVpost. However, the corresponding PTV analyses revealed no significant differences between any of the overlap volumes of any of the PTVs with the bladder, rectum, and penile bulb, but did reveal a significant difference between the PTVRIS and PTVpost overlap volumes with the symphysis compared with PTVpre overlap volumes with the symphysis. CONCLUSIONS: On RIS images, there appear to be areas of uptake in the bladder, rectum, and pubic symphysis but not the penile bulb; however, the dosimetric consequences of this uptake for radiation treatment planning are minimal on the bladder, rectum, and penile bulb, but require segmentation for dose reduction to the pubic symphysis.
AB - PURPOSE: The purpose of this study was to analyze regions of uptake in normal structures on postprostatectomy radioimmunoscintigraphy (RIS) images by evaluating differences in the overlap volumes of prostate fossa clinical target volume (CTV) and planning target volume (PTV) using correlative computed tomography (CT) images. MATERIALS AND METHODS: The electronic records of 13 patients who received external beam radiotherapy postprostatectomy and who underwent a vessel-based RIS/CT registration were reviewed. For each patient, the RIS-defined CTV (CTVRIS) was compared (in terms of the overlap volume with the surrounding bladder, rectum, pubic symphysis, and penile bulb) with the CT-defined CTVpre before this registration and also with CTVpost (the final target volume used for treatment). Similar analyses were done for PTVRIS, PTVpre, and PTVpost defined in each case to be the corresponding CTV + 1-cm margin. RESULTS: CTVRIS overlapped significantly more with the bladder, rectum, and symphysis, but not with the penile bulb, than did either the CTVpre or CTVpost. However, the corresponding PTV analyses revealed no significant differences between any of the overlap volumes of any of the PTVs with the bladder, rectum, and penile bulb, but did reveal a significant difference between the PTVRIS and PTVpost overlap volumes with the symphysis compared with PTVpre overlap volumes with the symphysis. CONCLUSIONS: On RIS images, there appear to be areas of uptake in the bladder, rectum, and pubic symphysis but not the penile bulb; however, the dosimetric consequences of this uptake for radiation treatment planning are minimal on the bladder, rectum, and penile bulb, but require segmentation for dose reduction to the pubic symphysis.
KW - Computed tomography
KW - Prostate cancer
KW - Prostatectomy
KW - Radioimmunoscintigraphy
KW - Radiotherapy
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U2 - 10.1097/01.rlu.0000200461.93250.a5
DO - 10.1097/01.rlu.0000200461.93250.a5
M3 - Article
C2 - 16495731
AN - SCOPUS:33744973992
SN - 0363-9762
VL - 31
SP - 139
EP - 144
JO - Clinical nuclear medicine
JF - Clinical nuclear medicine
IS - 3
ER -