STUDY ON THE REALIZATION OF A COMPACT PROTON ACCELERATOR FOR CANCER THERAPY

从患者生活质量的角度来看，放射治疗癌症值得注意，因为它具有保持身体功能的优点。特别是质子治疗已经变得很重要，因为它在生物效应上等同于X射线，并且除了它可以将辐射剂量定位到受影响部分的事实之外，还可以有效地利用大量的X射线治疗经验。为了使质子治疗在癌症治疗中得到广泛应用，我们研制了一台小型质子同步加速器，并进行了以下几方面的研究：1.采用组合功能点阵结构，具有体积小、操作方便的优点;作为慢束引出方法，我们采用了一种新的方案，即施加一个横向射频电场，使电子感应加速器的调谐保持恒定， ...更多信息 2.通过优化加速模式，降低了所需的加速电压，采用了非调谐的射频加速腔，避免了射频腔的复杂调谐。通过发明称为多馈入耦合的新的功率馈送方法，通过减少反射功率，所施加的RF功率的利用效率已经大大提高。本文介绍了一种适用于癌症治疗专用真实的质子同步加速器的射频加速腔。通过大功率测试，从产生的间隙电压、所需输入功率和温升等方面来看，该器件具有较好的实用性。3.采用频率纯度高的数字合成器，研制了一种微机板上的射频控制装置。利用该装置，只要根据磁场变化的步进频率控制足够精确，就可以不需要带束流位置和相位误差的反馈控制。因此，同步加速器的日常运行有望成为可能。少

Radiation cancer therapy is noteworthy from the point of view of quality of life of the patients because of the merit of keeping the function of the body. Especially proton therapy has become important because it is equivalent to the X ray in the biological effect and tremendous amount of experience of treatment with X ray can be effectively utilized in addition to the fact that it can localize the radiation dose to the affected part. In the present study, we have developed a compact proton accelerator for cancer therapy in order to enable wide spread use of proton therapy.In detail, the following studies have been advanced priented for proton synchrotron which can be easily operated with various energies.1.Combined-function lattice is adopted for the merit of compactness and eazy operation. As the slow beam extraction method, we have adopted the new scheme to apply a transverse RF electric field keeping the betatron tune to be constant, which is suitable for the synchronization of the … More beam irradiation with breathing of the patient.2.After the reduction of the required acceleration voltage by optimization of the acceleration pattern, we have adopted an untuned RF accelerating cavity, which avoided the complicated tuning of the RF cavity. By invention of a new power feeding method called multi-feed coupling, efficiency of utilization of the applied RF power has been largely improved by the reduction of reflection power. An RF acceleration cavity applicable to a real proton synchrotron dedicated for cancer therapy has been completed with the untuned type excited by a 2kW solid state amplifier. By the high power test, it is found to be well put to practical use from the points of view of generated gap-voltage, necessary input power and its temperature rise.3.An RF control device fabricated on the boards of the personal computer has been developed adopting a digital synthesizer with good purity of frequency. With use of this devive, feed back control with beam position and phase error is considered to become unnecessary if the step frequency control according to the change of the magnetic field is precise enough. Thus the daily routine operation of the synchrotron is expected to be possible. Less