Mills M D, Fajardo L C, Wilson D L, Daves J L, Spanos W J
Department of Radiation Oncology, University of Louisville, 529 South Jackson Street, Louisville, Kentucky 40202, USA.
J Appl Clin Med Phys. 2001 Summer;2(3):121-30. doi: 10.1120/jacmp.v2i3.2605.
Radiation performance characteristics of a dedicated intraoperative accelerator were determined to prepare the unit for clinical use. The linear accelerator uses standing wave X-band technology (wavelength approximately 3 centimeters) in order to minimize the mass of the accelerator. The injector design, smaller accelerator components, and low electron beam currents minimize radiation leakage. The unit may be used in a standard operating room without additional shielding. The mass of the accelerator gantry is 1250 Kg (weight approximately 2750 lbs) and the unit is transportable between operating rooms. Nominal electron energies are 4, 6, 9, and 12 MeV, and operate at selectable dose rates of 2.5 or 10 Gray per minute. D(max) depths in water for a 10 cm applicator are 0.7, 1.3, 1.7, and 2.0 for these energies, respectively. The depths of 80% dose are 1.2, 2.1, 3.1, and 3.9 cm, respectively. Absolute calibration using the American Association of Physicists in Medicine TG-51 protocol was performed for all electron energies using the 10 cm applicator. Applicator sizes ranged from 3 to 10 cm diameter for flat applicators, and 3 to 6 cm diameter for 30 degrees beveled applicators. Output factors were determined for all energies relative to the 10 cm flat applicator. Central axis depth dose profiles and isodose plots were determined for every applicator and energy combination. A quality assurance protocol, performed each day before patient treatment, was developed for output and energy constancy.
为使一台专用术中加速器投入临床使用，对其辐射性能特征进行了测定。该直线加速器采用驻波X波段技术（波长约3厘米），以尽量减小加速器的质量。注入器设计、更小的加速器部件以及低电子束电流可将辐射泄漏降至最低。该设备可在标准手术室使用，无需额外屏蔽。加速器机架的质量为1250千克（重量约2750磅），且该设备可在不同手术室之间运输。标称电子能量为4、6、9和12兆电子伏，可在每分钟2.5或10格雷的可选剂量率下运行。对于10厘米施源器，在水中这些能量下的D(max)深度分别为0.7、1.3、1.7和2.0厘米。80%剂量的深度分别为1.2、2.1、3.1和3.9厘米。使用美国医学物理学家协会TG - 51协议，对所有电子能量使用10厘米施源器进行了绝对校准。对于扁平施源器，施源器尺寸范围为直径3至10厘米；对于30度斜角施源器，直径范围为3至6厘米。确定了相对于10厘米扁平施源器的所有能量的输出因子。针对每个施源器和能量组合，测定了中心轴深度剂量分布和等剂量曲线。制定了一项在每天患者治疗前执行的质量保证方案，用于输出和能量稳定性检测。
