(Sunday, 7/12/2020) [Eastern Time (GMT-4)]
Room: AAPM ePoster Library
Purpose: Perform SABR pre-treatment verification using multiple dosimeters (alanine, nanoDot, PTW60019, and TLD100H) for three treatment sites of spine, scapula, and sternum and compare with the Eclipse treatment planning system (TPS) dose calculation.
Methods: ablative radiotherapy (SABR) pre-treatment verification was conducted for the multiple dosimeters after the assessment of its dose linearity, energy, directional, and dose rate dependence. Four different inserts were designed and fit into the in-house phantom (Rod-Phantom) to conduct SABR measurement for the spine, scapula, and sternum treatment site. Alanine signal intensity was read using Electron-paramagnetic resonance spectrometer ( Bruker EleXsys E500) of 9.5 MHz, and Harshaw QS 5500 was used to read the TLDs. The charge response of microDiamond (PTW60019) and the signal intensity of the exposed nanoDot OSL were read using Dose 1 electrometer and Microstar Reader (Landauer Inc.) respectively. Eclipse Anisotropic Analytical Algorithm (AAA) was used for Patient plan calculation.
Results: less significant influence was observed with all dosimeters for directional, dose-rate, and energy dependencies. For all the three treatment sites considered in this report, the data were performed in duplicate and expressed as mean ± SD of the measured and Eclipse treatment dose: Alanine (19.59 ± 0.24, 17.98 ± 0.15, 17.95 ± 0.18), nanoDot (19.70 ± 0.43, 17.05 ± 0.08, 17.95 ± 0.98), microdiamond (19.69 ± 0.05, 17.76 ± 0.65, 17.68 ± 0.63) and TLD100H (19.65 ± 0.38, 18.06 ± 0.70, 17.97 ± 0.20) respectively for spine, scapula, and sternum. The percentage difference of the dosimeters was within 2%, except TLD100H, with a 3 % difference. In particular, alanine and nanoDot recorded a percentage difference of <2 %.
Conclusion: result demonstrates that the dosimeters are reliable and give a high degree of consistency between the measured and Eclipse planned dose, and therefore prove to be useful dosimeters for patient SABR pre-treatment quality assurance.
Keywords
Photon Detectors, Quality Assurance, Treatment Verification
Taxonomy
TH- Radiation Dose Measurement Devices: Phantoms for dosimetric measurement
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