Room: Exhibit Hall
Purpose: To compare the effects of different treatment planning systems on the radiation dose of the tumor and on the surrounding normal tissue, by tissue equivalent personalized phantom.
Methods: 1. The production of phantom. Three-dimensional reconstruction was performed using a CT image of real patient, and an equal proportion phantom was prepared by 3D printing and filled with tissue equivalent material. The tumor, the muscle tissue, the normal lung tissue and the fatty tissue use different tissue equivalent materials. And retain a position in the tumor, the normal lung tissue, and the spinal cord, to insert ionization chamber to measure the actual value.2. The phantom did a CT scanning, and images were used in the TPS.3. TPS planning was done on the tumor site. The doses were calculated by three different algorithms, PBC and CCC, Monte Carlo algorithm, and compared. At the time of irradiation, the ionization chamber was inserted and the actual value was measured. 4. Comparing the value, and compared among algorithms.
Results: 1. The actual value: the tumor is 213.7cgy, normal lung tissue is 53.85cgy, spinal cord is 4.1cgy.2. The tumor: PBC is 215.1cgyã€?CCC is 214.6cgyã€?MC is 214.1cgy.3. Normal lung tissue: PBC is 52.5cgyã€?CCC is 54.4cgyã€?MC is 55.2cgy.4. The spinal cord Department: PBC is 1.9cgyã€?CCC is 4.4cgyã€?MC is 4.5cgy.5. For PBC, CCC, MC in the tumor and normal lung tissue, the difference between the actual measurements are not big, the tumor is 214.4Â±0.7cgy and the normal lung tissue is 53.85Â±1.35cgy. However, the PBC algorithm underestimates the dose at the spinal cord, the other two algorithms and the actual measurements are 4.3Â±0.2cgy, but PBC is 1.9cgy.
Conclusion: The phantom of tissue equivalent personalized phantom can improve efficiency of dose verification. Different algorithms of TPS have significant difference in spinal cord department.
Funding Support, Disclosures, and Conflict of Interest: Acknowledgement Fund Projects: National Key Research and Development Project (2016YFC0103400). J. Q. was supported by the Taishan Scholars Program of Shandong Province .