Mode of action
The mobile radiation source of INTRABEAM accelerates electrons with a maximum voltage of 50 kV onto a gold target. It is here that the low-energy X-ray radiation is generated and then emitted isotropically, penetrating the tissue to a depth of about 1-2 cm. The quality and constancy of the radiation have been well studied in dosimetry studies.
The electrons are generated and accelerated in the main unit and travel via the electron beam drift tube which is surrounded by the conical applicator sheath such that its tip lies at the epicentre of the applicator sphere. Once the electrons hit the inner surface of the hemisphere at the tip, x-rays are generated. Thus a uniform radiation dose rate is available at the surface of the applicator sphere.
The miniature X-ray source delivers up to 50kV of energy to the target tissue, and the steep dose fall-off ensures that most of the dose stays in the target tissue. The decrease in radiation protects surrounding healthy tissue and minimises shielding requirements.
Since there are no structural changes required for radiation shielding in the operating room, the system is easily integrated into the surgical workflow. Following tumor resection, the sterile applicator is anchored directly in the cavity maximizing dose delivery to the tumor bed. Electromagnetic couplings in the INTRABEAM carrier system provide the ability to lock the applicator into any required position during irradiation. The sterile applicator is joined with a sterile drape that is used to cover the stand during treatment delivery. Particularly sensitive structures can be covered with a mobile shield.
Irrespective of the applicator size or the type of tumor treated, the treatment duration is about 30 minutes on average.
More information about the INTRABEAM System you can get at Carl Zeiss.