The experimental determination of characters of radiation field for the prostatic hyperplasia applicator can provide indispensable dosimetric parameters and physical pictures of radiation field’s change for medical practice and the research on therapy mechanism. The dose distribution of the “rectum-type” 90Sr/90Y prostatic hyperplasia applicator with arc shaped source had been determined and the absorbed doses in 336 positions had also been obtained with the lithium fluoride (LiF) thermoluminescent dosimeters (TLD’s) chips in a water-organic glass phantom. Based on the magnetic deflection and organic glass filtrating technique

the research on share of bremsstrahlung radiation dose

DR

i.e. the ratio of bremsstrahlung radiation dose to total absorbed dose

was performed in air-organic glass medium and the results show that the ratio is dependent on the distance between applicator and detector

and at the position of the maximum range of β-particles for 90Sr/90Y

DR value does not exceed 0.15%. Using organic glass as tissue-equivalent material and BaF2 as detector for determining counts of nuclear radiation

rough physical picture of the change of the nuclear radiation from the applicator in tissue was obtained and it fully accorded with the change trend of the corresponding data in dosimetry.