Radiation sterilization for medical devices (syringes, dressings etc.) and tissues
Sterilization is defined as validated process used to render a product free from viable microorganisms and is described by an exponential function. Therefore, the presence of microorganisms on the individual item can be expressed in terms of probability. While the probability may be reduced to a very low number, it can never be reduced to zero. The probability can be expressed as a Sterility Assurance Level (SAL), it means probability of a viable microorganism being present on the product unit after sterilization.
There are several chemical and physical methods of sterilization. In the case of radiation sterilization, inactivation of microorganisms occurs either through direct ionization of a vital cellular molecule (DNA, key enzyme, etc.) or indirectly through the reaction of the free radicals produced in the cellular fluid.
For radiation sterilization one applied ionizing radiation from:
The choice of radiation source for a particular application depends on such requirements as product configuration, minimum dose, max/min dose ratio, economical factors, etc.
- radioactive isotopes (gamma rays from Co-60 or rarely, from Cs-137),
- particles accelerators (high-energy electrons).
The Institute has been promoted radiation sterilization with high-energy electrons for over 20 years. Two accelerators have been used for this purpose: LAE 13/9 and Elektronika 10/10. LAE 13/9 is the first accelerator installed in INCT and is used also for other tasks like polymer crosslinking or pulse radiolysis. Elektronika 10/10 is located at the Pilot Plant for Radiation Sterilization and is used only for radiation sterilization.
The main advantages of radiation sterilization are:
Radiation sterilization obviously does not induce radioactivity in irradiated products. Packed products, several in one cardboard box, are exposed to the action of 10 MeV electrons from accelerators on a conveyor.
- simplicity and ambient temperature of processing,
- continuous and quick operation,
- use of 100% tight packages,
- absence of residues after processing.
INCT provides the radiation sterilization service and takes responsibility for delivering the required dose.
For each irradiation run it is certified the delivery of the dose to the product.
The time limit of irradiation sterilization service is individually agreeded with the customer (usually it takes 1-3 days) and never exceed 2 weeks.