Exist in bemedical instrumentsUnder the stimulus of the market strong growthSterilizeThe demand has also risen, making various sterilization methods endless. Most disposable medical devices are made of polymers and can only withstand moderate temperature rise. For decades, the "low -temperature" sterilization method has been mainly based on two technologies of ethylene ethylene and gamma rays. Because the market is worried about the future supply capacity of such methods (whether it is reasonable or not) and its potential effects on global sterilization capacity, it once again ignites the enthusiasm of people seeking alternative technology, especially electronic beams and X -ray radiation sterilization sterilization sterilization technology.

Since the 1950s, electronic accelerators have been widely used in various industries, mainly used for polymer modification, such as polyethylene crosslinters of cable insulation. The use of electronic beams to medical devices can be traced back to the 1970s. Today, many mainstream medical device manufacturers have adopted electronic beam accelerators as an internal sterilization solution, and at the same time, the willingness to radiate electronic beam sterilization outsourcing is becoming increasingly strong. In 2011, the first high -power X -ray sterilization facility (now owned by Steris) was put into operation in Switzerland. Since 2020, the number of newly invested EB-X sterilization facilities has exceeded gamma sterilization facilities. In the United States (close to Dallas, Texas, Massachusetts, Nosblo, Illinois, Illinois), Germany, the Netherlands (Fenlo), and Thailand (Chunwuri) are all new X -ray sterilizers.

The accelerator is used as an ionized radiation source, and has the following advantages relative to the cobalt-60:

Durable electrical equipment can be obtained from many suppliers

Can be suspended from radiation emission

Safety characteristics ensure that it can easily meet relevant license and regulatory requirements

Gamma spokes characteristics:

The machine structure is very complicated, the budget budget is high, and the operation requires ultra -high professional qualifications. Usually it is necessary to sign a maintenance contract to ensure smooth use

You can run at full load immediately. You can freely meet the changes in market demand by adjusting the use time. The machine does not consume power when it is idle

Electronic accelerator

The accelerator is continuously increasing to the electrons generated by the machine, so that it is scanned by a beam form that moves with controllable speed, and the radiation dose is adjusted by speed. The acceleration method of electronics and the exposure of the product in the electronic bundle determine the type of machine. In addition to technical requirements, for users, another key factor is that the machine ensures that the product obtains the required radiation dose and dose distribution.

Electronic beam energy and power are the two major features of the accelerator:

The energy unit is a mesa electron volt (MEV) or a thousand electron volt (KEV), and the electron volt is a energy unit that can be converted into scorched ears. The energy determines the distance of the beam penetrating the product, and then determines the unevenness of the sterilization effect. The corresponding quantitative indicator is the maximum to the minimum dose ratio (dose uniformity ratio or DUR). Therefore, energy is a key factor in determining sterilization capacity for specific products and packaging types and density. Generally speaking, the higher the energy, the larger the machine, the area, and the required radiation barrier, the higher the investment cost.

For specific energy and target products, the accelerator throughput is proportional to the power (KW). The larger the system's energy, the shorter the time required for radiation. Power selection is a key decision, which must be properly selected based on the prediction results required in the next few years.

Electronic accelerators can be used to produce two ionizing radiation: electron beams and X -rays. The metal target is placed between the electron beam and the product emitted by the accelerator. X -rays are generated when the electron beam hit the target. Most of the incident electronics energy is dissipated in the form of heat, and only a small part is converted into X -ray, which also explains why X -rays failed to become a commercially available medical device sterilized before the emergence of ultra -high power, medium power and high -energy accelerators. Program. Compared with the absorption dose (the energy absorbed by the object (KGY) when the object is consumed), the electron beam is obviously more effective than the X -ray, but the range and flexibility of the wide X -ray product processing range and flexibility allows us to choose in the actual choice in the actual choice I have to make a choice.

Electronic beam or X -ray? Or do the two jointly use?

The electronic beam processing time is extremely short, and the sterilization dose that can be provided for gamma can be provided within a few seconds. This means that the use of high -power electron beam accelerators can achieve ultra -high throughput. Another benefit brought by the high dose is that the material oxidation time is extremely short, which helps minimize the negative effect on certain polymers.

The largest shortcoming accelerated electrons is that the product penetration ability is lower than the gamma ray or X -ray photon, which is because the electrons have quality and negative charge. Containers, test tube groups, surgical tray, ducts, etc.

For projects with only surface sterilization or (single packaging) thickness and density, you can use the low energy (80-300 KEV) or medium energy (maximum 5 MEV) electrons generated by the self-shielding device for inline sterilization. In the pharmaceutical industry, more than 30 units around the world use electronic beams for sterile filling. The container equipped with a glass syringe is purified in the electron beam tunnel to ensure that the sterile areas in the filling area are not polluted. Recently, a new type of inline electron beaming technology with pulse beam has also appeared.

When exceeding a certain packaging size or density, electronic beam sterilization within the specified dose range will no longer be feasible in technology. X -ray is a replacement method that does not involve radioactive substances in radiation sterilization. X -rays are composed of photons. The propagation and penetration characteristics are very similar to the photons in gamma rays. Its dose distribution is quite or even exceeded by gamma radiation, and the processing time is shorter. Its penetration and sterilization uniformity is quite or even better than gamma radiation, which can sterilize the entire tray.

The selection of electronic beams and X -rays depends on the size, density, geometric shape of the packaging, and the range of the smallest and maximum dose specified (the DUR ratio required).

The hybrid solution of dual technology systems (electronic beams and X -rays) can adapt to products with different DUR tolerances. The advantage of the dual system lies in flexibility. It can use one technology to sterilize certain products and sterilize other products with another technology. However, dual systems are inevitably dominated by a technology: or an electronic beam system with X -ray capabilities, or an X -ray system with electronic beam capabilities. Therefore, dual systems are a compromised solution that are used when they are used when they are very diverse when they need to sterilize.

Sterilization method change

The regulatory environment of medical device manufacturers often makes them conservative. Although gamma radiation is not necessarily the optimal choice, people are more familiar with it and this technology itself is simpler, so the resistance is smaller -especially for old -fashioned products that are too expensive for re -verification costs. Even at the regulatory level, promoting transformation may be hindered by lack of perception of electron beams, especially X -rays. The ISO 11137-1 standard specifies the three modes of radiation sterilization, but compared to the other two types of ionizing radiation, gamma radiation is still used much. In the past three years, participants in all parties have been trying to change the concept of medical device manufacturers.

Essence In 2020, the gamma and the electronic radiation team summarized the regulatory requirements of the transformation of radiation sterilization methods stipulated in the EN ISO 11137-1, especially when converting from gamma rays to X-rays (4). The Biotechnology System Alliance (BPSA) formulates a test method that enables many data certified by gamma rays to be fully applied to X -ray (5). The International Radiation Society (IIA) issued an accelerator buyer guide to help manufacturers only need to invest in decision -making (6). The American Medical Instrument Promotion Association (AAMI) will release the AAMI TIR 104 standard titled "Converted Products or Models between Radiation Places or Models" in early 2022.

in conclusion conclusion

Recent development clearly shows that among the existing sterilization methods, accelerator -based electronic beams and X -ray sterilization technology are becoming increasingly important. This is the result of multiple external factors superimposed, including: increased demand for sterilization capacity, cutting -edge thinking on the establishment of the establishment model, and the needs of sterilization ability risk management. At the same time, this is also the result of the technological progress and innovation of accelerators. The new machine design and components make them more reliable, and the functional implementation is greatly expanded and diversified -although there are still more complicated regrets, the improved interface makes the machine more user -friendly. In order to better cater to customers' pain points and expectations, many manufacturers have also reduced technical terms in wording. With the major sterilization contractor, X -ray sterilization has been added within the sterilization technology provided by them, and the situation that is not familiar with X -rays will soon change.