Room: Stars at Night Ballroom 4
Purpose: The aims of this study were to develop and evaluate the contact lens type ocular in-vivo dosimeter (CLOD) which detect the low dose delivered by treatment beam in head & neck cancer and its use in simulation.
Methods: CLOD was composed of three materials: LiPCDA, Tartrazine and Sorta clear 40. It was analyzed using an EPSON Expression 10000XL scanner. Various dosimetric evaluation of CLOD were investigated, such as the linearity, energy & dose-rate dependence, angular dependence and sensitivity to scanner orientation. In addition, the phantom study was conducted for three plans and the results were compared with the doses calculated by treatment planning system (TPS) and Monte Carlo (MC) simulation. Lastly, simulation was performed for patients in order to verify the use in clinical treatment.
Results: The results showed that the dose of CLOD is linearly related to the irradiated dose in the range from 10 to 1000 cGy. The dose sensitivity and linearity of the CLOD showed 0.0427 Î”OD/Gy and RÂ²value of 0.9975. CLOD was independent for energy, dose-rate, delivered angle and scanner orientation. The results of phantom study obtained using CLOD showed good agreement with the calculated doses, with an average difference of 5.85Â±2.22 cGy (TPS vs. CLOD) and 1.06Â±0.22 cGy (MC vs. CLOD), respectively. In simulation, the measured doses also showed an excellent agreement with the calculated dose using TPS.
Conclusion: The dosimetric characteristics of CLOD were studied in clinical photon beam. It shows that CLOD can be used as a dosimeter. Based on the results, it was found to be an acceptable dosimeter for measurement in clinical treatment beam for head and neck cancer.