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High-energy photons are emitted from a radio-isotope source (e.g., Cobalt 60). These photons can create ionization (electron disruptions) throughout a product.

No, absolutely not. It is like how one does not start emitting sunlight after being exposed to sunlight, which is UV radiation.

If you do not know the minimum dose for your product you may contact us. We can help you determine the dose requirement.

Dosimeters are measurement devices used to measure dose, and have a calibration that is traceable to national standards. The first time that your product is run, maximum and minimum doses are measured by placing several dosimeters around your boxes or product packages (product validation). A single reference dosimeter can then be used in future runs to verify that required doses have been achieved.

It is the amount of the energy that is absorbed by the ionizing radiation in the unit mass of the substrate. 1 Gy is 1 Joule of energy that is absorbed by a substrate weighing one kilogram. 1 Gy = 1 joule/Kg. The old unit of absorbed dose is rad. ( 1 Gy = 100 rad).

The activity of a radio active material is a measure of its spontaneous transformation. It is defined as the number of nuclear transformations ( or integration) per second. The SI unit of activity is bacquerel(Bq). 1 Bq = 1 transformation/sec. The old unit of activity is curie(Ci). 1 Ci = 37 x 109 transformation per second = 37 GBq.

Gamma irradiation has been applied with the aim of sterilization for a period longer than 50 years and there are more than 200 gamma irradiation plants in 55 countries world wide.

Usually all Irradiation plants operate on 24 x 7 system including weekends. The appropriate planning is performed upon the negotiations with the relevant people on the days and hours of the irradiation process either before or after the arrival of the products to the facility and the client is informed accordingly.

(For Medical Products) The VDmax25 option (ISO11137: 2006) is convenient when a company wants several product lines sterilized at the same minimum dose, when product is expensive to make, or for companies with markets where a 25 kGy dose is the accepted standard. Furthermore, the validation is less expensive because fewer tests are necessary. Bioburden counts must be 1000 CFU or less. Method 1 (from 11137-2) determines the lowest sterilization dose necessary for the determined bioburden population. This Method should be used when the lowest possible sterilization dose is desired due to cost considerations, use of gamma sensitive materials, or when the bioburden count is above 1000 CFU.

(For Medical Products) Performed early in product qualification, materials can be screened for compatibility with irradiation. Pre- and post irradiation properties related to functionality and appearance must be evaluated to determine maximum dose. Irradiating your product at a dose approximately 2.0 times that of the minimum (or greater), then testing the product’s form, fit, and function, is an excellent way to establish maximum dose. Setting the maximum dose as high as possible allows the greatest flexibility in processing schedules when product is ready for routine sterilization. Accelerated aging and package testing are additional tests to be considered for product irradiated at the maximum dose.

(For Medical Products) In order to test a dose for SAL 10-6, one million products would need to be irradiated and sterility tested. SAL 10-2 (Method 1) or SAL 10-1 (VDmax) is used because only 100 or 10 products, respectively, must be used for the experiment.

Bacillus pumilus, a spore-forming micro-organism, served for many years as a biological indicator to test for sterility. Its use today has been discontinued. The radiation resistance of B. pumilus is generally lower than the dose required to achieve a 10-6 SAL based on the bioburden typically seen on healthcare products. BI also do not accurately represent natural form of bioburden on a product (spore strip vs. actually in or on product as a result of manufacture).

A manufacturer is free to select this test as a basis for release, but the radiation sterilization process must first be validated. After validation has been completed using accepted techniques, such as those found in the ANSI/AAMI/ISO guideline, dosimetric release can be used. Dosimetric or parametric release is a form of product release after sterilization that is based on the proper clearance rather than on a sterility test.

The use of BIs for validation or release of product is not recommended for radiation sterilization because there are some organisms that have a greater resistance to radiation than Bacillus pumilus, which is the standard BI organism used for radiation. The use of calibrated dosimeters to confirm dose delivery can also be accomplished as well as the dosimetry release of product without sterility testing.

A Certificate of Irradiation is provided with every lot of gamma radiated material. This document is generated by the irradiation facility itself and provides information about when the material was processed and what dosage of radiation the material actually received, product description, quantity, batch nos. etc.

Gamma Radiation Sensitive Indicators are used to identify products exposed to radiation. Prior to the irradiation procedure, a label is affixed on each product box with Clients Name, Order Registration Number, date of registration, box serial No. etc. On this label itself, radiation sensitive indicator(yellow color) is also affixed in one corner. Upon exposure to gamma irradiation, this indicator label changes color from yellow to red. This system provides customer an assurance that each box is exposed/irradiated.

Irradiation indicators are not an indication of sterility. They indicate that product has been exposed to irradiation. The color changes from yellow to red due to a shift in pH. Indicators are typically placed on the outer packaging (on the case) for inventory control purposes. Indicators can also be placed on inner packages. Under some conditions such as high heat, prolonged UV light, direct sunlight or exposure to alkaline conditions the irradiation indicators may turn orange or orange-yellow. Because of this they should not be depended upon to indicate sterility of the product.