(Sunday, 7/12/2020) [Eastern Time (GMT-4)]
Room: AAPM ePoster Library
Purpose: A single isocenter multiple target stereotactic radiosurgery program was commissioned from concept and comparison to current institution SRS practices to treatment delivery system validation and patient specific QA.
Methods: A single isocenter multiple target stereotactic radiosurgery treatment planning system was obtained by the institution and plans were created to compare to patients with multiple metastases previously treated with multiple isocenters. Metrics were compared between the two plan techniques by physicians and physicists and absolute chamber measurements were acquired for each target in the single isocenter plans. Phantom plans were created with various target sizes and distances from the single isocenter and chamber measurements to determine limitations and treatment planning guidance. End to end tests were completed with three gel phantoms obtained and analyzed by a third party. Absolute film dosimetry was completed in two planes for each target in the gel phantom test plans and diode array measurements were performed.
Results: Comparison of metrics between single isocenter multiple target and multiple isocenter multiple target treatment plans confirmed clinically acceptable use of the new treatment technique in the institution. Comparison of chamber measurements, gel phantom irradiation, absolute film dosimetry, and diode array measurements with gamma analysis down to 3% and 1mm validated treatment delivery of the new treatment technique in the institution.
Conclusion: An accurate and safe single isocenter multiple target stereotactic radiosurgery program was commissioned at our institution using various equipment and third party validation.
Funding Support, Disclosures, and Conflict of Interest: Brainlab provided the funding for the one gel phantom from RTSafe.
Keywords
Commissioning, Gel Dosimeter, Stereotactic Radiosurgery
Taxonomy
TH- External Beam- Photons: intracranial stereotactic/SBRT
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