Requirements for Radiation Therapy Installations

PURPOSE: This rule establishes requirements for radiation therapy installations. (1) The radiation source housing shall be a protective therapeutic type. (2) Permanent diaphragms or cones shall be used for collimating the useful beam and shall afford the same degree of protection as the radiation source housing. Adjustable or removable beam-defining devices shall not transmit more than five percent (5%) of the useful beam obtained at the maximum kilovoltage and with the maximum treatment filter. (3) The filter system shall be so arranged as to permit proper filter selection and alignment. Filters shall be secured in place to prevent them from dropping out during treatment. The filter slot shall be so constructed that the radiation escaping through it does not exceed one (1) roentgen per hour at one (1) meter. (4) The radiation source shall be centered and mounted so that it cannot turn or slide with respect to the aperture when the source is in the on position. (5) Means shall be provided to immobilize the radiation source during stationary radiation treatment. (6) A timer shall be provided to terminate the exposure after a preset time. (7) With equipment operating above sixty (60) kilovolts peak (kvp), interlocks shall be provided so that when any door to the treatment room is opened, either the machine will be shut off automatically or the radiation level within the room will be reduced to an average of not more than two (2) milliroentgens per hour and a maximum of ten (10) milliroentgens per hour at a distance of one (1) meter in any direction from the target. After this shutoff or reduction in output, it shall be possible to restore the machine to full operation only from the control panel. (8) The control shall be located outside of the treatment room or within a protective booth. (9) Equipment utilizing shutters to control the useful beam shall have a shutter position indicator on the control panel. (10) There shall be on the control panel some easily discernible device which will give positive information as to whether or not the source of the ionizing radiation is in the on position. AUTHORITY: section 192.420, RSMo 1986.* This rule was previously filed as 13 CSR 5090.180. Original rule filed Nov. 9, 1964, effective Dec. 9, 1964. *Original authority: 192.420, RSMo 1963.