摘要:

Conformal irradiation system of HIMAC has been up‐graded for a clinical trial using a technique of a layer‐stacking method. The system has been developed for localizing irradiation dose to target volume more effectively than the present irradiation dose. With dynamic control of the beam modifying devices, a pair of wobbler magnets, and multileaf collimator and range shifter, during the irradiation, more conformal radiotherapy can be achieved. The system, which has to be adequately safe for patient irradiations, was constructed and tested from a viewpoint of safety and the quality of the dose localization realized. A secondary beam line has been constructed for use of radioactive beam in heavy‐ion radiotherapy. Spot scanning method has been adapted for the beam delivery system of the radioactive beam. Dose distributions of the spot beam were measured and analyzed taking into account of aberration of the beam optics. Distributions of the stopped positron‐emitter beam can be observed by PET. Pencil beam of the positron‐emitter, about 1 mm size, can also be used for measurements ranges of the test beam in patients using positron camera. The positron camera, consisting of a pair of Anger‐type scintillation detectors, has been developed for this verification before treatment. Wash‐out effect of the positron‐emitter was examined using the positron camera installed. In this report, present status of the HIMAC irradiation system is described in detail. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1619911

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

Glassy Polymeric Carbon (GPC) has medical applications owing to its inertness and biocompatible characteristics. Commercial GPC prosthetics include mitral, aortic and hydrocephalic valves. Surface treatment of GPC increases the adhesion of endothelic tissue on GPC and avoids the occurrence of thrombus in cardiac implant. In this work, ion beam was used to improve the mechanical characteristics of GPC surface. Hardness was measured as a function of depth in precursor and GPC samples heat treated from 300 to 2500 °C before and after bombardment with energetic ions of silicon, carbon, oxygen and gold at energies of 5, 6, 8 and 10 MeV and fluences between 1.0×1013and 1.0×1016ions/cm2. Comparison shows that hardness increases of the bombarded samples depend on heat treatment temperature. We verify that ion bombardment promotes carbonization due to an increased linkage between the chains of the polymeric material in lateral groups that are more numerous for samples heat treated to 700 °C. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1619912

出版商:AIP    

年代:1903

数据来源: AIP