How efficient are metal-polymer and dual-metals-polymer non-lead radiation shields?

INTRODUCTION: Lead shields are often used to attenuate ionising radiations. However, to make lighter, recyclable and more efficient shields compared to lead, combinations of new metallic compounds together with polymer, for example, flexible polyvinyl chloride (PVC) have been developed recently. In this study, the capabilities of non-lead radiation shields made of one or two metallic compounds and polymer were evaluated. METHODS: Monte Carlo (MC)-based BEAMnrc code was used to build a functional model based on a Philips X-ray machine in the range of radiographic energies. The MC model was then verified by IPEM Report 78 as a standardised global reference. The MC model was then used to evaluate the efficiency of non-lead-based garments made of metallic compound and polymer (MCP) including BaSO4 -PVC, Bi2 O3 -PVC, Sn-PVC and W-PVC, as well as dual-metallic compounds and polymer (DMCP) including Bi2 O3 -BaSO4 -PVC, Bi2 O3 -Sn-PVC, W-Sn-PVC and W-BaSO4 -PVC. The absorbed doses were determined at the surface of a water phantom and compared directly with the doses obtained for 0.5 mm pure lead (Pb). RESULTS: Bi2 O3 -BaSO4 -PVC and W-BaSO4 -PVC were found to be efficient shields for most of the energies. In addition to the above radiation shields, Bi2 O3 -Sn-PVC was also found to be effective for the spectrum of 60 keV. Bi2 O3 -BaSO4 -PVC as a non-lead dual metals-PVC shield was shown to be more efficient than pure lead in diagnostic X-ray range. CONCLUSION: Combination of two metals-PVC, a low atomic number (Z) metal together with a high atomic number metal, and also single-metal-PVC shields were shown to be efficient enough to apply as radiation protection shields instead of lead-based garments.

Construction a CO2 Incubator for Cell Culture with Capability of Transmitting Microwave Radiation.

Background: The objective of this study was to design and construct a CO2 incubator with nonmetallic walls and to investigate the viability of the cells and microwave irradiance inside this incubator. Methods: Because the walls of conventional incubators are made of metal, this causes scattering, reflection, and absorption of electromagnetic waves. We decided to build a nonmetallic wall incubator to examine cells under microwave radiation. Incubator walls were made using polyvinyl chloride and Plexiglas and then temperature, CO2 pressure, and humidity sensors were placed in it. Atmel® ATmega1284, a low-power CMOS 8-bit microcontroller, collects and analyzes the sensor information, and if the values are less or more than the specified limits, the command to cut off or connect the electric current to the heater or CO2 solenoid valve is sent. Using a fan inside the incubator chamber, temperature and CO2 are uniforms. The temperature of the points where the cell culture plates are placed was measured, and the temperature difference was compared. Ovarian cancer cells (A2780) were cultured in the hand-made and commercial incubators at different times, and cell viability was compared by the MTT method. Microwave radiation in the incubator was also investigated using a spectrum analyzer. The survival of cells after microwave irradiation in the incubator was measured and compared with control cells. Results: The data showed that there was no significant difference in temperature of different points in hand-made incubator and also there was no significant difference between the viability of cells cultured in the hand-made and commercial incubators. The survival of irradiated cells in the incubator was reduced compared to control cells, but this reduction was not significant. Conclusion: This incubator has the ability to maintain cells and study the effects of electromagnetic radiations on the desired cells, which becomes possible by using this device.