Technical Report No. 5-86
Low energy (soft) X rays; dosimetry and cell survival
Hoshi M, Antoku S, Russell WJ, Miller RC, Nakamura N, Mizuno M, Nishio SEditor’s note: A publication based on this report was published in Int J Radiat Biol 54:577-91, 1988.
Summary
Dosimetry of low-energy (soft) X rays produced by the SOFTEX Model CMBW-2 was performed using Nuclear Associates Type 30-330 PTW, Exradin Type A2, and Shonka-Wyckoff ionization chambers with a Keithley Model 602 electrometer. Thermoluminescent (BeO chip) dosimeters were used with a Harshaw Detector 2000-A and Picoammeter-B readout system. Beam quality measurements were made using aluminum absorbers; exposure rates were assessed by the current of the X-ray tube and by exposure times. Dose distributions were established, and the average factors for non-uniformity were calculated. The means of obtaining accurate absorbed and exposed doses using these methods are discussed.
Survival of V79 cells was assessed by irradiating them with soft X rays, 200kVp X rays, and 60Co gamma rays. The relative biological effectiveness (RBE) values for soft X rays with 0, 0.2, 0.7 mm added thicknesses of aluminum were 1.6, which were compared to 60Co. The RBE of 200kVp X rays relative to 60Co was 1.3.
Results of this study are available for reference in future RERF studies of cell survival.
Dosimetry of low-energy (soft) X rays produced by the SOFTEX Model CMBW-2 was performed using Nuclear Associates Type 30-330 PTW, Exradin Type A2, and Shonka-Wyckoff ionization chambers with a Keithley Model 602 electrometer. Thermoluminescent (BeO chip) dosimeters were used with a Harshaw Detector 2000-A and Picoammeter-B readout system. Beam quality measurements were made using aluminum absorbers; exposure rates were assessed by the current of the X-ray tube and by exposure times. Dose distributions were established, and the average factors for non-uniformity were calculated. The means of obtaining accurate absorbed and exposed doses using these methods are discussed.
Survival of V79 cells was assessed by irradiating them with soft X rays, 200kVp X rays, and 60Co gamma rays. The relative biological effectiveness (RBE) values for soft X rays with 0, 0.2, 0.7 mm added thicknesses of aluminum were 1.6, which were compared to 60Co. The RBE of 200kVp X rays relative to 60Co was 1.3.
Results of this study are available for reference in future RERF studies of cell survival.