[Measurements of radiation depth-dose curves of radiotherapy device RTA]

Depth doses for radiation of superficial x-ray therapy unit RTA were measured in tissue-equivalent medium using an ionizing chamber. The measurements were made for high voltage (30-80 kV), treatment cone 8 cm in diameter and source-surface distance 30 cm. Necessary correction of the results was performed and the estimated error on a half-dose level was equal to 5.3% in 95% confidence interval. The results were in good agreement with Markus and Kasten's data but in disagreement with the data from current guide of practice on superficial x-ray therapy and the difference in half-dose level was up to two times.