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A Cognitive Fusion-guided Prostate Biopsy Using Multiparametric Magnetic Resonance Imaging and Transrectal Ultrasound
Published on: March 21, 2025
Quantification of prostate and seminal vesicle interfraction variation during IMRT
Steven J Frank1, Lei Dong, Rajat J Kudchadker
1Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA. sjfrank@mdanderson.org
International Journal of Radiation Oncology, Biology, Physics
|January 22, 2008
Summary
Interfraction variations in prostate and seminal vesicle (SV) position during intensity-modulated radiotherapy (IMRT) were quantified. Rectal and bladder volume changes significantly impacted prostate and SV positioning, necessitating daily target localization.
Area of Science:
- Radiation Oncology
- Medical Physics
Background:
- Prostate cancer radiotherapy requires precise targeting of the prostate and seminal vesicles (SVs).
- Interfraction motion, influenced by organ volume changes, can affect treatment accuracy.
Purpose of the Study:
- To quantify interfraction variability in prostate and SV positions during intensity-modulated radiotherapy (IMRT).
- To assess the impact of rectal and bladder volume changes on target positioning.
Main Methods:
- 15 prostate cancer patients undergoing IMRT were studied.
- In-room CT scans were acquired weekly using a CT-on-rails system (369 scans total).
- Prostate, bladder, rectum, and pelvic anatomy were contoured; volumetric and positional changes were analyzed relative to planning CT.
Main Results:
- Mean systematic interfraction variation for prostate and SVs was quantified across anteroposterior, superoinferior, and lateral axes.
- The mean 3D displacement vector was 4.6 mm for the prostate and 7.6 mm for the SVs.
- Rectal and bladder volume changes correlated with anterior and superior displacement of the prostate and SVs.
Conclusions:
- Prostate and SV variations were most significant in the anteroposterior and superoinferior directions.
- Systematic variations highlight the need for daily target localization or immobilization techniques in IMRT for prostate cancer.
