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SU-E-J-169: 4D-PET for Abdominal Tumor Target Volume Generation
Medical Physics
|May 19, 2017
Summary
Four-dimensional PET (4D-PET) imaging increases target volume delineation for upper-abdominal tumors compared to conventional PET. This technique accurately measures tumor motion, potentially enabling personalized radiation margins for improved treatment.
Area of Science:
- Oncology
- Medical Imaging
- Radiation Therapy
Background:
- Accurate target volume delineation is crucial for effective radiation therapy.
- Tumor motion, particularly in the upper abdomen, poses challenges for precise targeting.
- Conventional PET imaging may not fully account for respiratory-induced tumor movement.
Purpose of the Study:
- To evaluate the impact of 4D-PET on target volume delineation for upper-abdominal tumors.
- To compare 4D-PET delineation with conventional un-gated PET.
- To assess the ability of 4D-PET to measure tumor motion.
Main Methods:
- Respiratory-correlated FDG PET/CT (4D-PET) was performed on four patients with upper-abdominal tumors.
- Internal Target Volumes (ITVs) were contoured on 4D-PET (using end-inhale and end-exhale phases) and un-gated PET.
- Tumor motion and volumetric differences between the two methods were analyzed.
Main Results:
- In two tumors with significant motion and FDG uptake, 4D-PET volumes were 21-28% larger than un-gated PET volumes.
- Un-gated PET volumes were largely contained within 4D-PET volumes (93-95%).
- Tumor motion, primarily superior-inferior, measured 5.6-6.4 mm, with evidence of deformation.
Conclusions:
- 4D-PET accurately estimates motion for FDG-avid upper-abdominal tumors.
- Utilizing 4D-PET expands target volumes compared to un-gated PET in specific patient groups.
- 4D-PET facilitates patient-specific margins, potentially enhancing target coverage and reducing normal tissue dose.
