Assessment of Changes of Bladder Volume and Rectal Volume Using 4DCT Scan During External Beam Radiotherapy for Cervical Cancer- Observation Study

Our aim is to use 4 dimensional computed tomography (4DCT) to predict to changes of bladder volume and rectal volume during external beam radiotherapy for cervical cancer.

A total of 145 CT scans (29CT simulation and 116- 4D CT scans) from 29patients with cervical cancer patients who were planned for external beam radiation therapy (EBRT) were analyzed. 4DCT scan would be used to measure bladder volume and rectal volume changes. After taking the 4DCT scan, images are exported to treatment planning system, the target volumes and organs at risk (OARs) are contoured according to Radiation Therapy Oncology Group (RTOG) guidelines. Bladder volume and rectal volume measured in all the CT images.

Results: In our study we analyzed 29 patients for bladder and rectal volume during radiation, mean value for bladder volume was 5.2–5.7cm (SD ± 0.8) and greenhousegeisser test shows results of significant difference in bladder volume (p < 0.001). Also difference of rectal volume, mean value for rectal volume was 2.3–2.4 cm (SD ± 0.4)and greenhouse-geisser test shows results of no significant difference in rectal volume (p–0.565) in baseline image and all 4DCT scans.

In our study during external beam radiation therapy in carcinoma cervix shows significant change of bladder volume with insignificant changes in rectal volume. Keywords: Carcinoma cervix, 4 dimensional computed tomography, external beam radiation therapy, bladder volume, rectal volume.