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. 2021 Mar 1;55(s3):17-26.
doi: 10.2345/0899-8205-55.s3.17.

Potential Induced Radioactivity in Materials Processed with X-ray Energy Above 5 MeV

Hervé Michel, Thomas Kroc, Brian J McEvoy, Deepak Patil, Pierre Reppert, Mark A Smith

Potential Induced Radioactivity in Materials Processed with X-ray Energy Above 5 MeV

Hervé Michel et al. Biomed Instrum Technol. .

Abstract

Section 5.1.2 of ANSI/AAMI/ISO 11137-1 states that "the potential for induced radioactivity in product shall be assessed." This article describes how compliance with this requirement may be achieved using qualified test methods. Materials of consideration are conceptually discussed, and results of testing conducted on products processed with a 7.5-MeV X-ray irradiation process are provided. As X-ray becomes more widely used in healthcare sterilization, having standard assessment protocols for activation coupled with a shared database of material test results will benefit manufacturers seeking to utilize this innovative technology.

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Figures

Figure 1.
Figure 1.
Principle of photonuclear effect (X,n).
Figure 2.
Figure 2.
Total photonuclear cross-section as a function of the photo energy.
Figure 3.
Figure 3.
Principle of neutron capture.
Figure 4.
Figure 4.
Process for conducting an assessment of the probability of induced radioactivity occurring at levels higher than exemptions limit. *The limited numbers of nonmetal components in a healthcare product that may be activated during X-ray sterilization have negligible probability of exceeding exemptions levels. †Many plastics, dyes, and coloring agents contain metal constituents. If the presence of such agents is unknown, answer “yes” for this evaluation. ‡For these steps, if the response is “unknown” or “indeterminate,” answer “yes.”
Figure 5.
Figure 5.
Ludlum Model 54A Small Article Monitor installed at STERIS Libertyville X-ray Radiation Technology Center. Image courtesy of STERIS.
Figure 6.
Figure 6.
Ludlum Model 54A Small Article Monitor with source-positioning device. Image courtesy of STERIS.
Figure 7.
Figure 7.
Experiment to establish count time for screen instrument.
Figure 8.
Figure 8.
Germanium Hyper-Pure spectrometer. Image courtesy of STERIS.
See this image and copyright information in PMC

References

    1. Smith MA. Evaluation of activation in medical products from electron beam processing at energies slightly above 10 MeV. Radiation Physics and Chemistry . 2008;77(9):1079–87.
    1. Grégoire O, Cleland MR, Mittendorfer J, et al. Radiological safety of medical devices sterilized with X-rays at 7.5 MeV. Radiation Physics and Chemistry . 2003;67(2):149–67.
    1. Smith MA. Evaluation of potential induced radioactivity in medical products as a function of electron energy in electron beam sterilization. Radiation Physics and Chemistry . 2012;81:57–63.
    1. ANSI/AAMI/ISO 11137-1:2006/(R)2015 & A1:2013 & A2:2019 Sterilization of health care products—Radiation—Part 1 Requirements for development validation and routine control of a sterilization process for medical devices . Arlington, VA: Association for the Advancement of Medical Instrumentation;
    1. International Atomic Energy Agency Natural and induced radioactivity in food . www-pub.iaea.org/MTCD/Publications/PDF/te_1287_prn.pdf Accessed March 1, 2021.