| 摘要 |
Radiotherapeutic apparatus (see figure 1) comprising: a patient support 10; magnetic coils 16 disposed around the patient support for creating a magnetic field; a radiation source 30 producing a beam of radiation directed toward the patient support and mounted on a gantry 28 rotatable around the patient support; and a plurality of slip rings 40, 42, 44 for conveying electrical power to the radiation source; a plurality of contacts 50, 52, 54 for electrically coupling the slip rings to the radiation source, and one or more non-conducting barriers 70, 72 between adjacent contacts for preventing formation of arcs between the contacts. The insulating barriers allow power to be delivered to the radiation source at an elevated voltage e.g. 10kV or higher, reducing the current in the slip rings and minimizing interference on the magnetic fields associated with the coils. A step-down transformer between the slip rings and the radiation source and/or a step-up transformer before the slip rings can be provided to "correct" the voltages. An insulating barrier 60, 62 may also be between the slip rings. The magnetic coils allow patient location monitoring using MRI. |
