X-ray Sterilization Research Articles

Radioactivity and GMO-Free Sterile Insect Technology for the Sustainable Control of the Invasive Pest Drosophila suzukii.

Drosophila suzukii (D. suzukii), commonly known as the spotted wing drosophila, is a highly invasive crop pest that is difficult to control using chemical insecticides. To address the urgent need for alternative and more sustainable control strategies, the sterile insect technique (SIT) is improved, which involves the release of sterilized male insects to mate with fertile conspecifics, thereby reducing the size of the pest population in the subsequent generation. The three critical aspects that influence the success of SIT programs in D. suzukii are addressed. First, an accurate and nondestructive method is established to determine the sex of individual insects based on the differential weight of male and female pupae. Second, conditions for X-ray sterilization are systematically tested and an optimal dose (90kV/40Gy) is identified that ensures the efficient production of sterile D. suzukii for release. Finally, the inherent thermosensitivity of D. suzukii males is exploited to develop a temperature-based sterilization technique, offering an alternative or additional SIT method for this pest. These advances will contribute to the development of a comprehensive and effective strategy for the management of D. suzukii populations, reducing their impact on agriculture and helping to safeguard crop yields.

Toward Enhanced Machine-Based Release in X-ray Sterilization.

Trends toward the use of irradiator parameter release (also called machine-based release) put pressure on equipment manufacturers to guarantee accuracy and reliability of monitored process parameters. In the specific case of X-ray processing, relevance of these monitored parameters is questionable due to the additional difficulty coming from the fact that the X-ray converter does not have associated parameters or a monitored feedback mechanism. To bridge this gap, this article presents a novel method to verify in real-time consistency of certain X-ray field properties. It covers the description of an X-ray flux monitor and its experimental characterization. The proposed detector can be used as a control and monitoring tool in addition to the conventional "passive" dosimetry per ISO 11137-1 and ISO 11137-3. It can detect photon flux deviation on the order of magnitude of 1%. Its performance would allow real-time monitoring of each pallet being processed and ensure that the correct X-ray beam is directed to the product. Further, the known response of the detector to a product can serve as a validation that the correct product is in front of the beam. Moreover, a detector of this type could contribute to moving from the current dosimetric release to irradiator parameter release. Compared with current practices, benefits would include an increased number of control points used to verify process conformity, real-time information on the radiation field (process output validation), limited manual handling of dosimeters, and verification that the product treated is the same as the performance qualification dose-mapped product.

Effect of Gamma and X-ray Irradiation on Polymers Commonly Used in Healthcare Products.

Synthetic organic polymers commonly are used in the construction of healthcare product and medical device components. Medical devices often are sterilized to ensure that they are free from viable microorganisms. A common technique to achieve this is using ionizing radiation, usually gamma. A trend exists in industrial sterilization to supplement gamma with alternative accelerator technologies (e.g., X-ray). In the current work, studies were performed to characterize polymer modifications caused by gamma and X-ray sterilization processes and to assess the comparative equivalency. The studies were developed to evaluate two key process parameters: dose and dose rate. Three commonly used polymers were selected: high-density polyethylene, low-density polyethylene, and polypropylene. Four grades of each family were chosen. The dose assessment involved sample exposures to both gamma and X-ray irradiation at two dose levels (30 and 55 kGy). All other processing conditions, including dose rate, were controlled at standard processing levels akin to each sterilization technology. The dose rate assessment expanded on each dose level by introducing two additional dose rate parameters. Subsequent laboratory testing used techniques to characterize physico-chemical properties of the polymers to ascertain equivalency across test groups. Initial results indicated positive levels of equivalency between gamma and X-ray irradiation.

Soil (microbial) disturbance affect the zinc isotope biogeochemistry but has little effect on plant zinc uptake

Zinc (Zn) is an important micronutrient but can be toxic at elevated concentrations. We conducted an experiment to test the effect of plant growth and soil microbial disturbance on Zn in soil and plants. Pots were prepared with and without maize and in an undisturbed soil, a soil that was disturbed by X-ray sterilization and a soil that was sterilized but reconditioned with the original microbiome. The Zn concentration and isotope fractionation between the soil and the soil pore water increased with time, which is probably due to physical disturbance and fertilization. The presence of maize increased the Zn concentration and isotope fractionation in pore water. This was likely related to the uptake of light isotopes by plants and root exudates that solubilized heavy Zn from the soil. The sterilization disturbance increased the concentration of Zn in the pore water, because of abiotic and biotic changes. Despite a threefold increase in Zn concentration and changes in the Zn isotope composition in the pore water, the Zn content and isotope fractionation in the plant did not change. These results have implications for Zn mobility and uptake in crop plants and are relevant in terms of Zn nutrition.

Effects of X-ray irradiation on the fitness of the established invasive pest fall armyworm Spodoptera frugiperda.

Spodoptera frugiperda has spread to Africa, Asia, and Oceania, posing a serious threat to global agriculture. We estimated the appropriate dose of X-ray sterilization for S. frugiperda using an X-ray irradiation instrument to investigate environmentally acceptable control techniques, laying the framework for future applications of sterile insect technology (SIT) to manage the pest environmentally-friendly. This study is the first to investigate the effects of X-ray irradiation on the growth, development, survival, reproduction, and flight of S. frugiperda. The results showed that irradiation with 50-400 Gy had no significant effect on pupal eclosion, but females were more sensitive than males in terms of reproductive parameters, especially when doses of radiation were > 350 Gy. After irradiation with a sub-sterilizing dose of 250 Gy, the parental sterility rate was > 85%, and the sterility traits could be passed on to their offspring, resulting in a continuous decrease in the population of F1 and F2 generations. Our laboratory experiments theoretically confirmed the feasibility of SIT for controlling S. frugiperda in the field using X-ray radiation. This study provides a theoretical basis for future regional pest management strategies. © 2022 Society of Chemical Industry.

Change in Radiation Sterilization Process from Gamma Ray to X-ray.

The terminal sterilization of sterile orthopedic implants is a key process that, in addition to providing sterility, changes the material properties of the product and packaging. These changes might be observed during functionality testing and/or biological evaluation. We are establishing an additional sterilization process that appears promising from both a technical and business perspective. Our project aims to add X-ray sterilization to the established gamma sterilization for metallic hip and shoulder implants. To limit complexity, we started with a narrow product range. The main steps of our project journey are described here. Given that X-ray sterilization remains relatively new in terms of understanding the changes that might occur for product materials and functionality compared with changes observed following gamma radiation processing, this article highlights key steps in the change from gamma ray to X-ray sterilization.

X-Ray-Based Irradiation of Larvae and Pupae of the Navel Orangeworm (Lepidoptera: Pyralidae).

The suitability of adult male the navel orangeworm, Amyelois transitella (Walker) for Sterile Insect Technique (SIT) has been reported for both high energy gamma (>1 MeV) and low energy x-ray (90 keV) sterilization. However, research regarding sterilization of NOW larvae and pupae by gamma irradiation indicated nonsuitability due to high mortality. Here, NOW larvae and pupae were irradiated to doses up to 50 Gy with 90 keV x-rays, then paired with nonirradiated colony mates. Sterility of surviving insects was determined by the presence or absence of hatched neonates. While presence of offspring does not guarantee viability, the absence does guarantee sterility (as is appropriate for SIT) and was thus the measure used here. Early stage larvae experienced 77% mortality at a dose of 30 Gy, versus 20% for nonirradiated control. At 40 Gy, mortality reached 98%. Of surviving early stage larvae at 30 Gy, 29% of moth pairs produced offspring. For late stage larvae, no offspring were produced at 40 Gy, but mortality was 73%. For pupae, mortality reached 53% at 30 Gy with 13% still producing neonates, while mortality reached 98% at 40 Gy. These results are consistent with reported results for gamma irradiation of NOW larvae where sterility was observed somewhere between the 30 Gy and 60 Gy data points, but mortality was high. This further confirms the lack of suitability of NOW irradiated in the larval stage, whether by gamma or x-ray, and supports the hypothesis that x-ray and gamma treatments are biologically equivalent at equal doses.

X-ray: An Effective Photon.

Following years of discussion and debate regarding the economics of X-ray radiation for sterilization of healthcare products, the benefits of the technology are now being realized. X-ray, like gamma radiation, is a process whereby energic photons penetrate to sterilize medical devices. Compared to gamma, photons in the bremsstrahlung spectrum from X-ray radiation allow for improved dose uniformity ratio, higher dose rates, and shorter process time, which provide additional opportunities for sterilization process enhancement. Such improvements may be realized in a number of ways: 1) economic, where more products may be processed on a carrier; 2) improved dose range fit; and/or 3) wider material compatibility. Despite noted benefits, X-ray sterilization has not yet been widely accepted and currently accounts for less than 5% of the contract sterilization market. This article brings X-ray sterilization into focus by sharing knowledge and experience gained over the past 10 years at the STERIS Däniken site, with an aim to identify opportunities for future medical device sterilization.

Curcumin and Quercetin as Potential Radioprotectors and/or Radiosensitizers for X-ray-based Sterilization of Male Navel Orangeworm Larvae

Two natural compounds (quercetin and curcumin) were tested as sensitizing or protecting agents for Navel Orangeworm (NOW) larvae under x-ray sterilization, with the aim to reduce required doses and thus facilitate the substitution of x-ray for radioisotopes. The compounds were added to NOW diet at concentrations between 0 and 1.0 mmol kg−1 and subsequent reared male larvae were subjected to x-ray irradiation (90 keV, 9 mA) to doses up to 15 Gy. Upon emergence as adults, surviving male NOW were paired with colony virgin females and placed in isolation for observation of deformity, mortality, and fertility. Treatments included rearing larvae on infused diet before irradiation, after irradiation, and both. Results were tabulated as percentage of insects that were dead/deformed, infertile, or fertile and subjected to chi-squared analysis. While insect populations subjected to quercetin treatments were not found to be significantly different from control at any x-ray dose, all curcumin treatments yielded significant differences at an absorbed dose of 10 Gy, both in terms of decreased mortality and fertility. While none of the treatments resulted in acceptable mortality/deformity rates, the observed effects strongly support the need for continued testing of natural compounds for their efficacy to reduce required dose levels for sterilization.

Effects of X-ray irradiation on haemocytes of Procambarus clarkii (Arthropoda: Decapoda) males

The red swamp crayfish Procambarus clarkii is an invasive alien species spreading worldwide. The sterile male release technique (SMRT) is among the methods used to contrast the growth of P. clarkii populations within invaded areas. In this study males underwent X-ray sterilisation with a dose of 40 Gy and their immunocompetence was analysed in comparison to untreated animals to ascertain whether radiation can affect welfare parameters other than reproductive organs. The present research investigated the immune function in P. clarkii males in term of (1) morphological haemocyte characterisation by transmission electron microscopy to identify the main phagocyting haemocyte after in vivo artificial non-self challenge with latex beads; (2) total and differential haemocyte counts; and (3) basal and total phenoloxidase activities as components of the humoral defence. Three types of circulating haemocytes were characterised via transmission electron microscopy: hyaline, semigranular and granular haemocytes. The ultrastructural features of haemocyte granules allowed the characterisation of a fourth type of haemocyte, the medium granule haemocyte. In vivo artificial non-self-challenge with latex beads identified the semigranular haemocytes as primarily involved in phagocyting activity. Circulating haemocytes of males irradiated with a dose of 40 Gy, after 20 days, showed a significantly lower diameter in the granules of hyaline and semigranular haemocytes, but no other evident ultrastructural alterations in comparison with un-irradiated animals were found. Irradiated males showed a significant decrease of about 80% of circulating haemocytes and an increase in frequency of semigranular and granular haemocytes. No significant differences in basal and total phenoloxidase activity were recorded and this could, in part, explain the good survival level of irradiated males despite the drastic decline of the haemocyte number. This study represents the basis to appraise whether SMRT affects important functions, such as those of the immune system, in addition to altering the gonad tissue.

X-ray sterilization of insects and microorganisms for cultural heritage applications

The APAM (Development of Particle Accelerators and Medical Applications) Laboratory of the ENEA Frascati Research Center is engaged in the preservation of cultural heritage as part of the COBRA (Sviluppo e diffusione di metodi, tecnologie e strumenti avanzati per la COnservazione dei Beni culturali, basati sull’applicazione di Radiazioni e di tecnologie Abilitanti) project addressed to the transfer of innovative technologies and methodologies from research to small and medium enterprises involved in the restorative measures. This work aims to demonstrate the effectiveness of ionizing radiation on the disinfection of biodegraded art objects. The conventional methods for the disinfestation of works of art, using chemicals toxic to humans and environment, might cause some damage to the treated material even on micrometric scale (i. e. either cellulose degradation). Ionizing radiations interact with the infesting biological material causing an irreversible DNA degradation. For this reason, they are certainly suitable for removal treatments of both macro organisms and bacterial colonies. A 4.8MeV electron linear accelerator, normally dedicated to the characterization of dose detectors and radiographies, has been employed to produce Bremsstrahlung X-rays through a lead converter. The spectral fluence of the radiation source has been calculated using the Monte Carlo MCNPX code.The dosimetric characterization of the radiation field has been made using radiochromic films sensitive in the dose range of our interest (from 50 to 500Gy) calibrated with a Markus ionization chamber. The irradiation of the artifact prototypes are made within a lead shielded room at a variable distance from the X-rays source. Samples subjected to irradiation consist of a soil bacterium, Agrobacterium rhizogenes, and an insect, Stegobium paniceum, that are found as wall paintings invasive coloniser and as a pest of books, wood works and paintings, respectively. Tests of irradiation have been performed on pest organisms as well as on woods mock-ups to evaluate potential damage to the material during the sterilization. The growing capacity of the treated bacterial cells re-cultured at the end of the treatment was evaluated on the bacterial sample and resulted to strongly inhibit cell growth during post-irradiation incubation, so that after incubation periods at 28°C, no significant cell growth was observed. The induced levels of insect mortality and sterility vs absorbed dose and operative conditions have been also evaluated, demonstrating the induction of full sterility since the lower dose and 40% mortality by two days after the higher dose treatment. The experiments proved the ability to efficaciously treat objects of cultural heritage with X-rays in order to prevent the increase of the biodeterioration without damaging the materials: in fact, mechanical tests on both irradiated and not irradiated woods have demonstrated the absence of any induced degradation after the radiation exposition.

X-ray sterilization with accelerators is viable in US

X-ray sterilization with accelerators is viable in US

Managing of Procambarus clarkii by X-ray sterilisation of males: Cytological damage to gonads

Procambarus clarkii is an invasive alien species spreading worldwide. It is therefore mandatory to find new methods to manage this species since traditional techniques are not sufficient for this purpose. The present study investigates gonad damage induced by different doses of ionising irradiation: 20, 40 and 60Gy. Testis were analysed after 10 and 30 days by means of light, scanning and transmission electron microscopy. Control unirradiated testes present an acinar structure with a well-defined germinative cells maturation from the distal proliferative zone to the proximal stalk of the lobes whilst, in irradiated testes, induced apoptosis of germinative and accessory cells and a high level of vacuolisation inside the acini were identified, progressively increasing in accordance to Gy dosage and time after exposure. We determined the dose of 40Gy as the best compromise: it causes an extensive damage to germinative tissues without affecting crayfish vitality, differing from 60Gy. From an applicative point of view, this dose reduces the efforts, in terms of cost and time, for the application of SMRT.

X-ray sterilization of the An. arabiensis genetic sexing strain ‘ANO IPCL1’ at pupal and adult stages

With a view to area wide integrated pest management programs with a sterile insect technique (SIT) component against the malaria vector Anopheles arabiensis, the effects of X-ray exposure of males of the genetic sexing strain (GSS) of An. arabiensis, “ANO IPCL1” have been tested. The suitability of X-ray was assessed in comparison to gamma-ray for mosquito sterilization in operational settings where the acquisition of gamma ray irradiators may be problematic.Pupae and adult males were sterilized using X-ray irradiation at 5 increasing doses and effects were observed in terms of fecundity and fertility. Irradiated pupae and adults were further observed for effects on longevity.The adult stage appeared to be more sensitive to radiation exposure than the pupal stage, with a residual fertility of 1% in adults irradiated at 75Gy and 0% at 105Gy, compared to 8%at 75Gy and 4% at 105Gy in adults irradiated at the pupal stage. All treatment groups except those irradiated at 60Gy were statistically different from the control groups in terms of adult longevity post treatment, however overall survival was not highly compromised in the 75Gy treatment group which showed 96% of induced sterility. To ensure the fine balance between the induced sterility and the fitness of the insect produced is achieved, irradiation of adults at this dose may be a good compromise for the SIT as applied for this species, especially in specific cases such as sterilization after female elimination by spiking blood meals.Investigation into the combined effects of blood spiking and irradiation at the adult stage and additional competitiveness studies both in laboratory and field cages will provide more insight into the radiation dose and mosquito stage to be used in the frame of future SIT programs targeting this important malaria vector.

X-ray versus gamma irradiation effects on polymers

Today, the most common methods used for medical device sterilisation are by gaseous ethylene oxide and by electron beam or gamma irradiation. With X-ray sterilisation about to enter the market, its material compatibility needs to be assessed at doses typically encountered during a sterilisation process. This paper reports on a study that compares the effects of exposing different types of plastics that are commonly used in medical devices to 60Co or to 5 MeV X-rays. The dose rate for both irradiation modalities was of the same order of magnitude. Under these conditions, both types of radiation are found to have similar effects on polymer properties.

Preparation of twelve candidate agricultural reference materials

A cost-effective approach to monitoring and maintaining reliability of analytical procedures is by the incorporation of appropriate, compositionally similar reference materials into the scheme of analysis. Agricultural and food commodities represent an extremely wide range of composition, in respect of the sought-for analyte and the supporting material (matrix), not fully reflected in currently available biological reference materials (BRM's). With the view to attempting to fill some of the gaps in the world repertoire of reference materials and to have suitable products for our laboratories' use, preparation has been completed of twelve candidate agricultural reference materials. These products, representing a number of food classes, include bovine muscle powder, hard red spring wheat flour, soft winter wheat flour, durum wheat flour, wheat gluten, corn bran, corn starch, potato starch, whole egg powder, whole milk powder, microcrystalline cellulose, and sugar. Preparative steps included, as required, freeze drying, grinding or ball milling, X-ray sterilization, sieving, blending and packaging to yield sizeable quantities of each material in finely powdered form. Cooperative analytical effort is expected to lead to characterization in respect of concentrations of a number of nutritionally, toxicologically and environmentally-pertinent, major, minor, and trace chemical elements. These materials will then be available for analytical chemical data quality control for inorganic constituents in a range of agricultural commodities.

Resistance of the Prenatal Female Mouse to X-ray Sterilization

Resistance of the Prenatal Female Mouse to X-ray Sterilization

X-ray sterilization of immature female rats.

SUMMARY 1. Judged by the absence of germ cells, direct X-irradiation of ovaries of weanling rats at a level of 3150 and 4400 r leads to sterilization. Sterilization was often incomplete following exposure to 2200 r. The animals were kept under observation for 12 weeks after irradiation. Daily vaginal smears were taken after the rupture of the vaginal closure membrane. The age at which the vagina opened was about the same in animals sterilized at the age of 21–29 days as in their litter-mate controls. The rupture of the closure membrane was somewhat delayed in animals exposed to 4400 r at 18–20 days, and in unilaterally ovariectomized animals exposed to 4400 r at 23–26 days. Complete atrophy of the uterus did not occur within the experimental period of 12 weeks. The degree of involution corresponded to that of the ovaries. Changes in body weight and the weight of the pituitary and thymus were similar to those observed in adult rats following X-ray sterilization. 2. Treatment with gonadotrophins immediately after X-irradiation (at the age of 19–24 days) led to a less rapid breakdown of the vaginal closure membrane in rats exposed to 4400 r than in either similarly treated litter-mates exposed to 3150 r or their non-irradiated controls. 3. Treatment with gonadotrophins during the 5 days preceding X-irradiation (at the age of 23–26 days) was followed by an increase in subsequent secretion of oestrogen, as judged by the pattern of vaginal smears and the weight of the uterus.

The effect of x-irradiation on the secretory capacity of the testis.

SUMMARY The production of androgenic hormone (as judged by the weight of the accessory sex organs) was not diminished in the course of 25 weeks following exposure of the testes of rats to 5000 and 10,000 r of X-rays. The characteristic changes in the weights of the pituitary and adrenal glands which usually follow castration were not observed in the X-ray sterilized animals. The seminiferous epithelium was completely destroyed and did not regenerate during the postoperative period of observation of 25 weeks. Most of the intertubular cells remained histologically normal after irradiation. The proportion of intertubular to tubular tissue was considerably higher in the irradiated than in the non-irradiated animals. X-ray sterilized animals, like their non-sterilized litter-mates, responded to the administration of gonadotrophin by an increased production of androgen. Copulatory activity was not influenced by X-ray sterilization. All matings except one were sterile. Females inseminated by irradiated males became pseudopregnant (as judged by vaginal smears).

The oestrous cycle of the adult rat after X-ray sterilization.

SUMMARY Oestrous cycles, as judged by vaginal smears, persist for a variable time after X-ray sterilization of the ovaries, but their phases do not synchronize with the growth and rupture of surviving Graafian follicles and the formation of corpora lutea. Cyclical fluctuations in the size of the uterus and the histological appearance of the vagina occur during but not after the first two oestrous periods following sterilization.