Good Morning,
Kindly highlight on the advantages of gamma radiation sterilization, what kind of hospital equipments can be used for this procedure. we have a cobalt-60 teletherapy unit and how can it be further utilized for this purpose? please reply to

Major uses of radiation sterilisation include disposable syringes, sutures, powders, dressings (e.g. adhesive tapes) or intravenous infusion sets. Generally a dose of 25 kGy is thought to be effective; to achieve this dose with a hospital unit is mainly a question of the exposure time. It is important to make sure that the radiation dose does not damage the product and its packaging. Control procedures must ensure that the recommanded dose reaches all points of the product to be sterilised. Monitoring has to be done by the use of dosimeters distributed in the load. Biological indicators are also available but are not used for validation of the sterilisation process nor for routine monitoring. I am afraid that the hospital will have serious problems to meet the requirements of the relevant standards like EN 552 (Validation and routine control of sterilisation by irradiation) or ISO 11137 (Validation and routine control - radiation sterilisation). In summary, I do not recommand the use of hospital radiation units intended for therapeutic purpose as sterilisers.

Prof. Dr. P. Heeg,
Head of Hospital Hygiene at the University Hospital of Tuebingen,
Calwer Str. 7/4,
D-72076 Tuebingen,
Germany

Dear,
Besides the aspects of validation and reproducibility treated by Prof. Heeg there is also a practical problem. The dosisrate of a Co source, used in a hospital unit, is too small for sterilization. It produces normally 200 rad/min (to 800 rad/min). It will take 208 (52) hours to attain the required 25 kGy (1 Gy = 100 rad).

Best regards,
Wim Renders