Interfraction prostate movement in bone alignment after rectal enema for radiotherapy.

Area of Science:

• Radiation oncology
• Medical physics

Background:

• Prostate radiotherapy requires precise targeting.
• Interfraction prostate movement can reduce treatment accuracy.
• Image-guided radiotherapy (IGRT) utilizes fiducial markers for setup verification.

Purpose of the Study:

• To evaluate the impact of rectal enemas on interfraction prostate displacement.
• To assess the effect on bone alignment (BA) in prostate cancer radiotherapy.

Main Methods:

• Retrospective analysis of IGRT data from 15 prostate cancer patients.
• Prostate position tracked using implanted fiducial markers and ExaxTrac/NovalisBody system.
• Bone alignment (BA) performed using kV X-ray images and CT planning data.

Main Results:

• Mean interfraction prostate displacement was 3.12±2.00 mm.
• Greater displacement observed in anterior-posterior and superior-inferior directions.
• A required margin of 4.97 mm was calculated for the clinical target volume.

Conclusions:

• Rectal enemas were associated with reduced interfraction prostate displacement.
• This intervention can potentially decrease the clinical target volume-to-planning target volume margin.
• Rectal enemas are a viable method to improve prostate radiotherapy precision.