Gamma Sterilization for Medical Devices: An Overview

For medical environments to remain safe and effective, sterilization of equipment and devices is essential. This procedure gets rid of all microbiological life, such as spores, fungi, viruses, and bacteria. Doing so is crucial to stopping the spread of illness, particularly during operations where sterile bodily fluids or tissues are involved. Sterilization lowers the possibility of infections related to healthcare, protecting patient safety.

In order to guarantee patient safety and high-quality care, the Food and Drug Administration (FDA) in the United States and other health organizations across the globe stress the significance of efficient sterilization techniques. Sterilization is therefore essential to healthcare delivery systems.

Sterilization of Medical Devices: The Techniques

Sterilization of medical devices is not limited to one unique way. A lot of devices, chemicals, and techniques are involved. Selecting the technique and the relevant chemical for sterilization depends on the availability of the method, the medical device being used, the material of the medical equipment, the technique of surgery, etc.

  • Prominently used sterilization methods include:
  • Steam sterilization
  • Flash sterilization
  • EtO (Ethylene Oxide) sterilization
  • Hydrogen Peroxide sterilization, and
  • Gamma sterilization, etc.

In this blog, we will take a deep overview into Gamma sterilization technique.

Introduction to Gamma Sterilization

Prior to use, medical supplies, tissue allografts, and food samples must be sterilized. Various forms of sterilization, such as dry heat, formaldehyde, ethylene oxide (EtO), gas plasma, peracetic acid, e-beams, and gamma radiation are typically employed for this purpose.

Gamma irradiation has become the prevailing technique for sterilizing most medical devices: sutures, gloves, gowns, face masks, dressings, syringes and surgical staplers are an example of products that could be sterilized with gamma radiations. In gamma sterilization, products in their final packaging are exposed to gamma radiations from Cobalt-60, a radioactive isotope of Cobalt-59. When Cobalt-59 decays, it emits one electron and two gamma rays. These energy-rich gamma rays effectively eradicate microorganisms from medical devices and tissue allografts during the sterilization process. Therefore, radiation sterilization is the only process that enables products to be sterilized in their packages with no significant increase in temperature and without the use of chemicals, which always involves the risk of residues. Even the inner surfaces of closed packages or components with complex geometrical shapes are safely and reliably sterilized by high-energy radiation. However, they also induce substantial alterations in the molecular structure of irradiated products, specifically vulnerable biologics like cytokines, chemokine, and growth factors. Therefore, this type of sterilization is not suitable for some kinds of polymers that could be degraded by radiations.

Benefits of Gamma Sterilization:

Gamma sterilization is helpful to other sterilization techniques because they provide

  • Better penetration regardless of the material’s density, type, and orientation.
  • Have more certainty regarding sterility of the equipment.
  • Their sterilization is does not depend on pressure and temperature
  • The products and items sterilized using gamma radiations do not become radioactive and have no harmful ecological impact.
  • Products can be sterilized in their packages.
  • No chemical residues.

Gamma Sterilization for PPE

PPE has been used across various industries for the past many years. However, it gained prominence during the Covid-19 pandemic, when healthcare workers and professionals working in medical facilities were required to wear them. Since a huge amount and constant supply of PPE was required during the pandemic, it was only fair to sterilize the existing PPE, so that overwhelmed supply chain did not arise. Thankfully, gamma-ray sterilization was available, and it ensured that the PPE remained useful even after being worn in harmful conditions.

Disadvantages of Gamma Sterilization

Gamma sterilization also has some disadvantages, such as:

  • It cannot be used on liquid products as they can get degraded easily.
  • Gamma sterilization is also used for sterilizing foods, and foods with high fat content cannot be adequately sterilized with this method.
  • Gamma rays can alter or discolor the texture of certain products.
  • Not suitable for some kinds of polymers.

Gamma radiation induces substantial modifications in the biomechanical characteristics of various anatomical components, including the epidermis, amnion tissue grafts, micronized amniotic membrane injectable products, and tendons. In a similar fashion, the physicochemical properties of polymer medical devices that are sterilized with gamma radiation are drastically altered, which has a substantial impact on their clinical utility.

Regulations & Standards Surrounding Gamma Sterilization

Like every other sterilization technique, gamma sterilization is also subject to regulations. Examples of the standards governing gamma ray sterilization include:

  • ISO 11137:2017 – Sterilization of health care products

The standard ISO 11137 has been broken into three parts, and part 3 contains guidance regarding dosimetry and measurement of gamma-ray dosage.

  • FDA

On April 11, 2023, the US FDA announced a Radiation Sterilization Master File Program. This voluntary pilot was meant for nine companies that sterilize with single-use PMA-approved medical devices with gamma radiation or EtO.

  • AAMI TIR35:2016/(R)2021; STERILIZAION OF HEALTHCARE PRODUCTS-RADIATION STERILIZATION-PRODUCT ADOPTION AND ALTERNATIVE SAMPLING PLANS FOR VERIFICATION DOSE EXPERIMENTS AND STERILIZATION DOSE AUDITS

This standard explains approaches to be taken regarding selection and auditing of sterilization dose, reducing the number of product items. This reduction must be ensured while achieving the desired SAL (Sterilization Assurance Level).

How TSQ and E can help Fulfill Regulations Regarding Gamma Ray Sterilization?

Gamma ray sterilization is widely used in hospitals, manufacturing, and food processing facilities. It is also employed to sterilize medical devices and surgical equipment. We are pioneers in the medical device manufacturing industry and our consultants possess the relevant expertise to help manufacturers fulfill relevant regulations, such as the MDR requirements on sterile products outlined in GSPR 23.3. We ensure that the process of consultation stays smooth and consistent throughout. Kindly contact us today.

About the Author

Waqas Imam

S. M. Waqas Imam is associated with TS Quality as a Regional Partner. He is also an ambassador of Medical Device Community. He is an Industrial Engineer by qualification and served the manufacturing industry since 2011. He is also IRCA CQI Lead Auditor of ISO 9001 and other management system standards. He had served as Quality Assurance and Regulatory Affairs Manager in QSA Surgical Pvt. Ltd. and Ultimate Medical Products. He managed requirements of ISO 13485:2003, EU directives, CE marking and FDA. He also served as Expert Blog Writer for 13485Academy and wrote expert articles on various topics of ISO 13485:2016.