ESTRO 38 Abstract book

S1193 ESTRO 38

into Velocity (Varian Medical Systems Inc., USA) for forward planning. DPS dose distributions achieved with eBT were then compared to those achieved with PSI. Results The total number of dwell points for eBT per patient ranged from 2 to 15. In all patients, dose coverages achieved with eBT were similar to the prescribed doses with those obtained in PSI. Dose constraints (e. g. D10, D1cc, Dmax) for organs at risk were met in all patients. The number of trajectories needed for adequate coverage was lower with eBT compared to PSI.

Conclusion eBT with a DPS approach was feasible for tumors initially treated with PSI.

E-posters Radiobiology

Electronic Poster: Radiobiology track: Radiobiology of particles and heavy ions EP-2158 The Apoptosis Mechanism and Injury of Heavy Ion Beam and X-ray Radiation on Malignant Melanoma Cell S. Li 1 , Q. Jin 1 , Z. Chao 1 , G. Dong-Wei 2 , L. Qiang 3 , Z. Hong 4 , J. Xiao-Dong 3 , L. Yang 4 1 Lanzhou General Hospital of PLA, Radiotherapy, Lanzhou, China; 2 Northwest Normal University, Biology, Lanzhou, China; 3 Modern Physics- Chinese Academy of Sciences, Medical Physics, LanZhou, China; 4 Modern Physics- Chinese Academy of Sciences, Radiation Medicine, LanZhou, China Purpose or Objective This study aims to investigate the influence of high LET heavy ion ( 12 C 6+ ) and low LET X-ray radiation on apoptosis and related proteins of malignant melanoma on tumor- bearing mice under the same physical dosage. Material and Methods C57BL/6J mice were burdened by tumors and randomized into three groups. These mice received heavy ion ( 12 C 6+ ) and X-ray radiation under the same physical dosage, respectively; and their weights and tumor volumes were measured every three days post-radiation. After 30 days, these mice were sacrificed. Then, median survival time (MST) was calculated and tumors on mice were proliferated. In addition, immunohistochemistry was carried out for apoptosis-related proteins to reflect the expression level. Results After tumor-bearing mice were radiated by heavy ion, MST improved and tumor volume significantly decreased in conjunction with the upregulated expression of pro- apoptosis factors, Bax and Cytochrome C, and the downregulated expression of apoptosis-profilin (Bcl-2, Survivin) and proliferation-related proteins (PCNA). Results indicated that radiation can promote the apoptosis of malignant melanoma cells and inhibit their proliferation. This case was more suitable for heavy ion ( 12 C 6+ ). Conclusion High LET heavy ion ( 12 C 6+ ) radiation could significantly improve the killing ability for malignant melanoma cells by inducing apoptosis in tumor cells and inhibiting their proliferation. These results demonstrated that heavy ion ( 12 C 6+ ) presented special advantages in terms of treating malignant melanoma. EP-2159 Influence of L-Dopa pretreatment on cellular features in T98G cells A. Facoetti 1 , C. Aprile 2 , M. Cavagnini 1 , M. Ciocca 3 , A. Iannalfi 2 , L. Lodola 4 , M. Marenco 4 , R. Nano 5 , F. Pasi 6 , M.G. Persico 7 , F. Valvo 2 , R. Orecchia 8 1 Fondazione CNAO, Radiobiology Unit, Pavia, Italy; 2 Fondazione CNAO, Radiation Oncology, Pavia, Italy; 3 Fondazione CNAO, Medical Physics Unit, Pavia, Italy; 4 Fondazione IRCCS Policlinico San Matteo, Struttura Complessa di Medicina Nucleare, Pavia, Italy ; 5 Università degli Studi di Pavia, Dipartimento di Biologia e Biotecnologie “L.Spallanzani”, Pavia, Italy; 6 Fondazione IRCCS Policlinico San Matteo, Struttura Complessa di Radioterapia, Pavia, Italy; 7 Università degli Studi di Pavia, Scuola Universitaria Superiore IUSS,