PREGNANCY AND RADIOTHERAPY - IS THERE AN ISSUE FOR FEMALE STAFF MEMBERS OCCUPATIONALLY EXPOSED TO RADIATION?

Abstract

When medical linear accelerators are operated at bremsstrahlung energies higher than 10 MeV-X, the radioactive materials produced by photonuclear reactions can cause an internal and external exposure to the staff. This survey includes measurements on medical linear accelerators of one major vendor. Photon energies range from 4 to 18 MeV-X. By means of photonuclear effects, radioactive substances are produced inside of the treatment head of the linear accelerator, in the walls, ceiling and floor of the vault, in air and in the patient itself. The actual dose rates, caused by the radioactive decay of the radioactive materials, is measured by commercially available ion chamber survey meter after switching off the beam in a timeline with respect to daily routine. Depending on energy of the bremsstrahlung and different daily routine procedures, the annual exposure for staff members, can add up to 3.5 mSv. Especially for pregnant and breast feeding female staff members it is important to avoid incorporation of radioactive material and to limit the external exposure. Working conditions have to be organized to keep the Radiation Protection Regulations with respect to prohibition of incorporation and limitation of exposure to the fetus as low as 1 mSv.