Purpose: To demonstrate the dosimetric accuracy of PRESAGE™, a new type of three‐dimensional dosimeter, when used in the Radiological Physics Center's (RPC) Head and Neck Phantom. Method and Materials: An IMRT treatment plan was developed for the RPC Head and Neck Phantom, which contained simulated planning target volumes and an organ at risk. A conventional dosimetry insert, containing radiochromic film and TLD, was in place while the IMRT plan was delivered. The insert was removed and replaced with a PRESAGE™ dosimeter and delivery of the IMRT plan was repeated. An additional PRESAGE™ dosimeter was irradiated to doses between 0.5 and 7.5 Gy with stereotactic beams to develop a calibration curve. The PRESAGE™ dosimeter was imaged using an OCT‐OPUS™ laser CT scanner 24 hours after irradiation. Two‐dimensional comparisons were performed between the treatment plan, the distribution measured with film/TLD and the distribution measured with PRESAGE™. Results: The PRESAGE™ dosimeter showed a monotonic and easily characterized response with dose. Optical density maps obtained following IMRT delivery were converted to dose and compared with the treatment plan and with film/TLD data. Film and PRESAGE™ data showed good agreement, and both indicated higher doses in the steep gradient region between the PTV and the organ at risk. Conclusion: This work demonstrated the use of PRESAGE™ as a dosimetric tool for the verification of IMRT treatments. The dosimeter provided a three‐dimensional distribution that was used for comparisons with treatment plan distributions. The investigation was supported by PHS grants CA 10953 and CA81647 awarded by the NCI, DHHS.
ASJC Scopus subject areas
- Radiology Nuclear Medicine and imaging