Program Information
Irradiation of Human Cell Lines Using Various Ions
Y Lin1*, C Tessa2 , A Rusek2 , S McMahon1 , T Kaminuma1 , K Held1 , (1) Harvard Medical School, Boston , MA, (2) Brookhaven National Laboratory, Upton, NY.
Presentations
SU-C-204-4 (Sunday, July 31, 2016) 1:00 PM - 1:55 PM Room: 204
Purpose: The purpose of this study is to investigate and quantify the biological effects of ion radiation using several human cell lines. We aim to answer the question of whether carbon ion the most ideal ion species for heavy ion radiotherapy.
Methods: The cells were irradiated at different positions along the pristine Bragg peak of several ions with different atomic number. The biological effectiveness was evaluated using the clonogenic cell survival assay. Irradiation of three human lung cancer cell lines and a fibroblast cell line were undertaken using the charged particle beam at the NASA Space Radiation Laboratory at Brookhaven National Lab. Four mono-energetic ion beams (carbon, oxygen, helium and lithium) were used to irradiate the cells. Water or media-filled T25 flasks were lined up along the beam line so that the cell-containing surfaces of the flasks were placed at a specific depth along the pristine Bragg curve. Four depths along the curve, representing entrance point, rising peak, peak and distal fall off, were selected to determine biological effectiveness. Gaf-chromic films were placed between the flasks to monitor the irradiation as soon as it was finished.
Results: For all ion radiations, the maximum cell killing effect occurs at either peak or distal fall off, depending on the cell lines. For instance, for the fibroblast cell line AGO1522, RBEs of 1.4, 1.2, 1.4 and 1.9 were observed at the Bragg peak for Helium, Lithium, Carbon and Oxygen ions. Comparing positions, RBEs of 0.9, 1.2, 1.4 and 1.8 were observed for carbon irradiation of AGO-1522 cells positions corresponding to entrance, rising peak, peak and distal fall off.
Conclusion: RBE values differ with position in the Bragg peak, ion species and cell line. Ions other than carbon may prove more effective in certain irradiation conditions and may contribute to optimized heavy ion therapy.
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