Related Experiment Videos
Variation in prostate position quantitation and implications for three-dimensional conformal treatment planning
E Melian1, G S Mageras, Z Fuks
1Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
Summary
The prostate moves in the pelvis due to bladder and rectal volume changes. This prostate motion can affect radiation doses to the target and nearby organs, impacting treatment accuracy.
Area of Science:
- Radiation oncology
- Medical imaging
- Pelvic anatomy
Background:
- Prostate motion during radiation therapy can lead to inaccurate dosing.
- Understanding prostate movement is crucial for optimizing treatment planning.
Purpose of the Study:
- To quantify prostate motion within the pelvis.
- To assess the impact of this motion on target and normal organ doses.
Main Methods:
- Utilized serial CT scans to track prostate (planning target volume - PTV) motion in 13 patients.
- Measured changes in bladder and rectal volumes.
- Correlated PTV displacements with organ volume changes and calculated dose effects.
Main Results:
- Prostate motion, quantified by PTV center of mass displacements, varied (SD: 0.12-0.40 cm).
- Motion was more pronounced superiorly and influenced by bladder/rectal volumes.
- Target border displacements could lead to underdosing (median 6% PTV < 95% planned dose) and affected rectal/bladder doses.
Conclusions:
- The prostate exhibits limited motion in the pelvis, influenced by bladder and rectal volumes.
- Quantified prostate motion provides data for refining radiation treatment field margins.
- Single CT planning scans may not fully capture dose delivery due to organ motion.