Intensity Modulated Radiation Therapy (IMRT) for patients with primary endometrial cancer: using volumetric imaging to cover what counts.

Abstract

Aim: The clinical uptake of bladder and bowel preparation guidelines in conjunction with volumetric imaging for patients receiving IMRT for gynecological cancers is relatively low when compared with prostate cancer practices [1]. This paper will describe an initial experience with an online image matching process using daily pre-treatment Cone Beam CT (CBCT) to assess critical structure and target volume displacement for patients with primary endometrial cancer undergoing radical IMRT. Methods and materials: CT Simulation Patient Preparation: Empty rectum and bladder prior to drinking 500 -750 mls of fluid. Simulation Procedure: Patient positioned supine on pelvic board and immobilized using a personalised vac-fix extending from the iliac crest to feet. Both full bladder and empty bladder CT scan are taken. Contrast agent used to enhance vaginal area. Patient Education: Fluid intake for planning CT scan and time allowed for bladder filling is recorded at CT... Results: Comparison of planning CT and CBCT images showed the effects of rectum and bladder motion on target volumes are extremely variable (refer to figures 4 and 5). This is consistent with results from previous studies suggesting the position of the vagina could be displaced by up to 2cm due to bladder filling variation [2]. Validity of planned treatment volumes is dependent on the consistency of rectum and bladder preparation [3] If rectal and bladder filling varies considerably from planned... Conclusion: An initial experience using a daily online image matching process for primary endometrial cancer patients undergoing radical IMRT allows therapists to assess the placement of target volumes relative to rectum and bladder filling. Patient education at CT simulation is imperative to ensure adequate preparation is undertaken for treatment. The consistency of rectum and bladder filling is an integral aspect of accurate treatment delivery for complex planning techniques in endometrial cancer.