Writer: Sterilization Time: 2020-09-14 Browse: 815 ℃
This list describes the mode of action, penetration ability, process parameters, advantages and disadvantages and cost of gamma irradiation.
| Mode of action | Ionizing radiation in the form of gamma rays |
| Medical device product requirements | Materials are compatible with radiation, penetrate full pallets with bulk density up to 0.40 g/cm3 |
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Material compatibility |
Wide range of polymer compatibility; some limitations due to oxidation effects— PTFE and PVC affected |
| Largest processing unit | Pallets or boxes |
| Processing |
Product exposed to gamma rays for a validated period of time to achieve a desired minimum dose Control system can raise or return sources from/to pool manually or automatically |
| Tolerance for density variation | High |
| Processing time for a typical 45-ft tractor trailer (~3,000 ft3) |
<24 hours typical but could process small batch quicker |
| Processing parameters |
There is a need to monitor cycle time and product size and density to ensure the prescribed dose is achieved |
| Product release parameters |
In order to release product to market, the following are required: • Control of the product manufacturing processes to ensure supply of material and product packaging is consistent with the validated radiation process • A validated processing configuration in which an array of dosimeters have been measured to demonstrate the relationship between processing parameters and minimum and maximum dose to product and a routine dosimeter measurement (validation requirements and methods are well described in ISO 11137-1) • A measurement of routine dose for a given processing run, which indicates that a dose within specification has been delivered. This measurement can be made as soon as the irradiation process is complete, so there is no required waiting time before release |
| Pros (specific to medical devices suitability) |
Gamma • 60-year proven track record • >40% of the world’s single-use medical devices are sterilized using Cobalt-60 • Simplicity of monitoring cycle time and density • Ability to schedule multiple products to be processed at one time • Reliability and dependability of the radiation source • Ability to process in large volume quantities (pallets) |
| Cons (specific to medical devices suitability) |
• Requires requalification of irradiator operation after source replenishments, which are typically annual (but can vary from 6 months to several years depending upon operational need) |
| Gamma Equipment | |
| Penetrating capability | Gamma radiation emitted by Cobalt-60 is used to penetrate pallets up to 120 cm thick at densities up to 0.4 g/cc in normal two-sided operation |
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System repair downtime (e.g.source/system for machine sources; system for Cobalt-60) |
Gamma Tends to be in the order of hours. Equipment issues generally related to conveyor can generally be repaired quickly. Source re-loading, approximately annually, takes between 24 and 72 hours |
| Reliability and maintenance | Stable and reliable due to the use of an isotope source and the simplicity of the product handling system. Actual operational experience has demonstrated ~95% uptime |
| Pros (equipment-related) |
• The Cobalt-60 energy allows processing of totes and carriers up to full pallets of healthcare products • No issues with respect to source reliability when resuming operations • Irradiators are extremely reliable because the source of radiation never fails • Flexibility to “grow” the irradiator as demand increases • Product handling systems are easily maintained, usually with in-house resources, with off-the-shelf components |
| Cons (equipment-related) |
Gamma • Cobalt-60 is radioactive material, which will require appropriate management at the end of the life of the source • Historically, world supply of Cobalt-60 is dependent on the availability and willingness of nuclear reactors that are capable of producing Cobalt-60 • Cobalt-60 requires scheduled reloading that might require downtime and some revalidation efforts |
| Sterilization source | Cost of generator Includes irradiator, pool, installation, IQ and OQ and initial loading of Cobalt-60. Production throughput is proportional to activity of Cobalt-60 loaded in the irradiator. Initial loading of isotope may be significantly lower than maximum capacity of facility and can be increased over time. Cobalt-60 transportation needs to be considered and can vary depending upon activity being transported, carriers utilized, routes followed and price of fuel. Treatment of Cost of Cobalt-60 as Capital Expense or OPEX can vary. |
| Process management |
Conveyor Typically tote or pallet conveyors with an ability to utilize a second conveyor allowing multiple products requiring different doses to be processed |
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Safety Systems The Safety Access System prevents unauthorized access into the irradiation chamber. Should there be an authorized intrusion in the irradiation area, the safety system instantaneously stops the conveyor and lowers the source rack to the bottom of the irradiator pool. |
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| Specific Infrastructure |
Shielding Shielding is usually made of concrete. A typical foot print for an x-ray or gamma irradiation system including shielding and conveyor is about 25m x 20m. |
| Irradiation Authorizations including compliance of design shielding and safety system according to standards. | |
| Ancillary systems Includes water cooling, compressed air, ozone venting, fire prevention | |
| Common infrastructure |
Land Building Warehouse Miscellaneous fences, racks, furniture, forklifts Local authorizations Building permits, fire department, environmental regulations such as noise |
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Variable costs Costs that are proportional to production |
Operators Operators typically work in shifts. Processing boxes requires more labor compared with pallet processing. |
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Power Consumption Minimal as it is only required to raise and lower source rack and operate the chiller for pool |
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| Conveyor power consumption | |
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Spare Parts Spare parts stock may vary. Due to the simplicity of Cobalt- 60 irradiators, spare parts are minimal and readily available compared to Accelerator based systems. Spare parts required for the conveyor are similar compared with e-beam and x-ray. |
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| Repairs / maintenance and ongoing Investment | Maintenance Engineer General conveyor/electrical maintenance background |
Email: jacky@huada-bio.com
Phone: +86 17665746669
Add: No 84.Banhe Road Guangzhou High-tech Industrial Development Zone Guangzhou Guangdong,China.