Variation of Indoor Average Ozone Concentration within the Radiation Therapy Room by High Energy Radiation

Abstract

This study was to evaluate the change in characteristics of concentration of ozone after exposure to high energy radiation in linac room. Background ozone concentration of linac room was measured and compared to ozone concentration around linac room. Background ozone concentration of linac room was mean 17.4±7.9 ppb. It was 50% of the ozone concentration(36.8±22.3 ppb) around linac room(p<0.05). The concentration of ozone after exposure to high energy radiation in linac room was elevated to double of background ozone level, intensity after exposure. with exposure time concentration of ozone increased proportionally. It showed maximum level at 130~180seconds and slowed a tendency to saturate. It required more than 10 minutes for ozone concentration in linac room to drop to ozone concentration around linac room. The concentration of ozone after exposure to high energy radiation is high enough to cause specific physical symptoms, such as acute dyspnea or chest pain due to dry cough. Exposure to high concentration of ozone in sealed linac room can aggravate pulmonary disease, so special attention is needed.

Measurement and Risk Analysis of Ozone (O3) Concentrations in the 9 MeV and 12 MeV Electron Mode LINAC

“…Ozone in our air can harm health, and ozone concentrations can reach unhealthy levels (Nuvolone et al, 2018). Ozone, which enters the body through human skin or the respiratory tract, is a potent chemically active gas that easily forms chemical bonds with surrounding substances and decomposes so that it can be broken down into proteins, lipids, and carbohydrates, which interact with the constituent materials to produce free radical oxidation, resulting in permanent damage (Lee et al, 2016). People most at risk of ozone exposure include people living with asthma, children, adults who have health problems in the body's systems, in this case, cervical cancer, breast cancer, etc., and people who are active in the room (radiation workers) are at greater risk of exposure (Guan et al, 2022;Nazaroff & Weschler, 2022;Salonen et al, 2018).…”

“…The average background ozone concentration was 17.4±7.9 ppb, which was 50% lower than the ozone concentration inside the LINAC room (36.8±22.3 ppb) (p<0.05). Ozone concentration doubled after exposure, and it took more than 10 minutes for the room's ozone concentration to decrease (Lee et al, 2016).…”