Related Experiment Video
Updated: Jun 27, 2026
06:08
A Cognitive Fusion-guided Prostate Biopsy Using Multiparametric Magnetic Resonance Imaging and Transrectal Ultrasound
Published on: March 21, 2025
Analysis of interfraction prostate motion using megavoltage cone beam computed tomography.
Kevin C Bylund1, John E Bayouth, Mark C Smith
1Department of Radiation Oncology, University of Iowa, Iowa City, IA, USA.
International Journal of Radiation Oncology, Biology, Physics
|November 19, 2008
Summary
Daily megavoltage cone beam computed tomography (CBCT) imaging reveals significant interfraction prostate motion, primarily in the anterior-posterior direction. This motion impacts radiotherapy margins, necessitating adjustments for accurate treatment delivery.
Area of Science:
- Radiation Oncology
- Medical Imaging
- Prostate Cancer Treatment
Background:
- Accurate patient positioning is crucial for effective radiotherapy.
- Interfraction motion, the movement of organs between radiation sessions, can reduce treatment accuracy.
- Megavoltage cone beam computed tomography (MV CBCT) offers daily imaging for precise patient alignment.
Purpose of the Study:
- To quantify the degree and components of interfraction prostate motion using daily MV CBCT.
- To assess the impact of interfraction motion on radiotherapy margins.
- To evaluate the reliability of MV CBCT for daily localization.
Main Methods:
- Retrospective analysis of 984 daily MV CBCT images from 24 prostate cancer patients.
- Pretreatment couch shifts used to measure interfraction motion.
- Off-line bony registration to differentiate bony misalignment from internal organ motion.
- Interobserver and intraobserver variation studies performed.
Main Results:
- Mean interfraction prostate motion was 6.7 mm, with greatest deviation in the anterior-posterior (AP) direction.
- Systematic deviations stemmed from bony misalignment; random deviations from both bony misalignment and internal motion.
- Implementing early-treatment motion offsets reduced AP planning target volume margins by 50%.
Conclusions:
- MV CBCT is a practical method for daily prostate localization.
- Significant interfraction motion necessitates adjustments to conventional radiotherapy margins.
- Findings are comparable to other interfraction motion measurement modalities.
Related Concept Videos
01:10Computed Tomography
Tomography refers to imaging by sections. Computed tomography (CT) is a non-invasive imaging technique that uses computers to analyze several cross-sectional X-rays to reveal minute details about structures in the body.
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...
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...
01:27Imaging Studies III: Computed Tomography
DefinitionComputed Tomography (CT) of the genitourinary (GU) tract is a non-invasive imaging modality that utilizes X-rays and computer processing to generate detailed cross-sectional images of the urinary system, encompassing the kidneys, ureters, bladder, and adjacent structures such as the adrenal glands.PurposeCT scans of the GU tract serve several diagnostic and therapeutic purposes, including:Diagnosis of Urinary Tract Diseases: Detects kidney stones, tumors, cysts, and congenital...