Beam characteristics of the therapax DXT300 orthovoltage therapy unit.

The operating performance and beam characteristics of a new orthovoltage unit, the Therapax DXT300, have been evaluated. Percentage depth-dose and backscatter tables are presented for several applicator sizes, at 30 cm and 50 cm focal skin distances (FSDS) and for multiple x-ray beam qualities with the tube operating between 100 and 300 kVp accelerating potential. The unit has been found to provide beam characteristics similar to those reported for other orthovoltage therapy machines. The linearity and short- and long-term stability/reproducibility of the unit's internal dosimetry system have also been studied, and results indicate a very stable beam output of better than 1% standard deviation. The data presented in this work should provide the basis for comparison with other units and act as a reference for clinics commissioning the Therapax DXT300 in the future.