Tom 67 (2022): Zeszyt 2 (June 2022)

The outbreak of the COVID-19 pandemic has shown that the demand for medical masks and respirators exceeds the current global stockpile of these items, and there is a dire need to increase the production capacity. Considering that ionizing radiation has been used for sterilization of medical products for many years and electron beam (EB) irradiation enables the treatment of huge quantities of disposable medical products in a short time this method should be tested for the mask’s decontamination. In this work, three different filtering facepiece respirators (FFRs) were irradiated with electron beams of 12 kGy and 25 kGy. The results confirmed that the decrease in filtration efficiency after irradiation of all respirators results from the elimination of the electric charge from the polypropylene (PP) fibers in the irradiation process. Moreover, the applied doses may affect the thermal stability of PP fabrics, while filtering materials structure and integrity have not changed after irradiation.

Breast cancer remains one of the major causes of mortality among female cancer patients. This fact caused a spark in the medical field, which in turn helped to improve the diagnostic and treatment of breast cancer patients over the years making this field always active with new ideas and innovative methods. In our study, a new method was explored using an energy-resolving detection system made from a NaI (Tl) scintillation detector to detect the gamma photons from an Am-241 radiation source to try and construct an image by scanning the American College of Radiology (ACR) mammography phantom. In addition to the experimental work, a Geant4 Application for Tomographic Emission (GATE) toolkit was used to investigate more complex options to improve the image quality of mammographic systems, which is limited by the experimental setup. From the experimental setup, the researchers were able to construct an image using the 26.3 keV and the 59.5 keV energy photons, to show the largest size tumour (12 mm) in the ACR phantom. With an improved setup in the simulation environment, the majority of the ACR phantom tumours was visible using both energy windows from the 26.3 keV and the 59.5 keV, where the 26.3 keV yielded better quality images showing four tumours compared to three when using 59.5 keV. The simulation results were promising; however, several improvements need to be incorporated into the experimental work so that the system can generate high-resolution mammographic images similar to the ones obtained by the GATE simulation setup.