The radio-resistance tests for E. Coli

α

-streptococcus

N-catanhalic

Candida albicans

Aspergillus rersico and Bacillus cureus spores by

60

Co

γ

-ray under the different doses were reported. From the logarithmic survive curve of irradiation

it was shown that D-values for the above spores were 0.2

0.4

0.35

0.5

0.75 and 1.3 kGy respectively. When the concentrations of spores were 10

6

—10

7

and absorbed dose was 7kGy

the efficiency of sterilization reached 99.9999%. The physical and chemical properties of PVC materials irradiated with 7-10kGy accorded with the pharmacopeia standard after the storage of 7 days to 8 months. The materials remained sterile and pyrogen-free after storage as long as 8 months.By the acute toxicity test and 220 cases of clinical test it was proved that this sterilization method was safe and reliable.