Related Experiment Video
Updated: Jan 14, 2026
Proton Therapy Delivery and Its Clinical Application in Select Solid Tumor Malignancies
Published on: February 6, 2019
Rectal motion can reduce CTV coverage and increase rectal dose during prostate radiotherapy: A daily cone-beam CT
Raj Sripadam1, Julie Stratford, Ann M Henry
1Clatterbridge Centre for Oncology, Bebington, Wirral, UK.
Background And Purpose:
Daily on-treatment verification cone-beam CT (CBCT) was used to study the effect of rectal motion on clinical target volume (CTV) coverage during prostate radiotherapy.
Material And Methods:
CBCT scans were acquired from 15 patients immediately after daily treatment. From these images, the rectum was contoured allowing the analysis of rectal volume cross-sectional area (CSA) and the determination of rectal dose. Rectal wall motion was quantified as a surrogate measure of prostate displacement and CTV coverage was subjectively assessed.
Results:
Rectal volume decreased over the treatment course in 13 patients (P<0.001). Rectal wall regions corresponding to the prostate base displayed the greatest motion; larger displacements were seen in patients with larger rectal planning volumes. CTV coverage was inadequate, at the prostate base only, in 38% of the fractions delivered to 4/7 patients with a large rectum at planning (>100 cm(3)). In patients with small rectum at planning (<50 cm(3)) up to 25% more rectal volume than predicted was included in the high-dose region.
Conclusions:
Rectal motion during treatment in prostate cancer patients has implications for CTV coverage and rectal dose. Measures to ensure consistency in daily rectal volume or image-guided strategies should be considered.
Related Concept Videos
01:27Imaging Studies III: Computed Tomography
01:28Imaging Studies for Cardiovascular System V: CT
01:26Imaging Studies III: Gastrointestinal Motility Studies and Virtual Colonoscopy
Radionuclide Testing
Radionuclide testing is a sophisticated medical technique for assessing gastrointestinal motility. It focuses on gastric emptying and colonic transit time. Radioactive markers track the movement of food through the digestive system, providing insights into gastrointestinal disorders.
In gastric emptying studies, a meal's liquid and...
01:30Radiological Investigation I: X-ray and CT
01:10Computed Tomography
The technique was invented in the 1970s and is based on the principle that as X-rays pass through the body, they are absorbed or reflected at different levels. In the technique, a patient lies on a motorized platform while a computerized axial tomography (CAT) scanner rotates...
01:14Imaging Studies I: CT and MRI
Description of the Procedures
Computed Tomography (CT) scan:
Computed Tomography (CT) scans use X-ray technology to generate detailed images of bones, organs, and tissues. During the scan, the patient lies on a moving table...