[Usefulness of Radiation Protection Cloths in Fluoroscopy with Clean Areas].

Lowering the dose limit for the lens of the eye incorporated into the Regulation on Prevention of Ionizing Radiation Hazards, effective on April 2021, and dose reduction will become more and more important in the field of radiation. Radiation protective cloth is used as a protective equipment in fluoroscopy rooms. Although it is usually used to protect staff from radiation exposure during endoscopic retrograde cholangiopancreatography, we investigated whether there is a way to use it for procedures in clean areas. Assuming ureterostomy fistula replacement in urology, the protective cloth was suspended on the side of the patient's head and posterior aspect of the tube, and the distance between the anterior aspect of the X-ray tube and the patient's foot was 55 cm. As a result of measuring the dose rate, a 10% dose reduction was obtained for the lens of the eye of the surgeon, and the distribution of air dose rate in the examination room was significantly reduced. Although scattered radiation from the radiation protection cloth appeared in some areas, the radiation dose to the patient was reduced throughout the body, and a high degree of radiation protection was obtained, especially for the lens of the eye. It is expected that the radiation protection cloths may be useful even when the length of the cloths is limited due to the cleanliness of the area.

In vitro biocompatibility of dextrin: the addition of a low concentration of dextrin in the medium promotes the cell activity of L929 mouse fibroblasts.

To develop a bone substitute with shape-generating properties, we focused our attention on dextrin, which has a low viscosity. After considering methods of evaluation for research and development, we started by using cells that are widely used for safe biological evaluations in the field of dentistry and conducted in vitro evaluations. In this experiment, we variously added concentrations of 0.1, 1.0 and 10 mmol/l of dextrin to a culture medium in order to examine the effects on L929 mouse fibroblasts in vitro. As a result, the proliferative activity of the L929 cells was promoted during the culture period as the concentration of added dextrin became lower, and in particular, the 0.1 and 1 mmol/l addition group showed higher values than those of the control group. From the above results, it was revealed that the addition of a low concentration of dextrin in a medium promotes the cell proliferative activity.

Effect of self-cured acrylic resin added with an inorganic antibacterial agent on Streptococcus mutans.

In order to develop an self-cured acrylic resin having an antibacterial property, three types of commercially available inorganic antibacterial agents were added, at 1% each, to UNIFAST III to evaluate the antibacterial property. The antibacterial test evaluated the amount of Streptococcus mutans attached to UNIFAST III, the residual viable count of Streptococcus mutans cultured on UNIFAST III. And the color tone changes evaluated immediate and temporal color tone changes of UNIFAST III caused by the addition of antibacterial agents. As a result, compared to UNIFAST III without any added inorganic antibacterial agent, a significant decrease was observed in the attachment amount and the residual viable count of Streptococcus mutans. In addition, when adding NOVARON from among the added inorganic antibacterial agents, UNIFAST III exhibited little change in the temporal color tone. Thus, these results suggest that the addition of antibacterial agents to resins is effective first step toward developing self-cured acrylic resins having an antibacterial property.