OAR 333-106-0210: Fluoroscopic X-ray Systems Requirements: Fluoroscopic Entrance Exposure Rates

(1) Fluoroscopic equipment manufactured before May 19, 1995 that is provided with Automatic Exposure Rate Control (AERC) shall not be operable at any combination of tube potential and current that will result in an exposure rate in excess of 10 roentgens (R) (2.58 mC/kg) per minute, at a point where the center of the useful beam enters the patient, except: (a) During the recording of fluoroscopic images; or (b) When optional high-level control is provided. When so provided, the equipment shall not be operable at any combination of tube potential and current that will result in an exposure rate in excess of 5 R (1.29 mC/kg) per minute at a point where the center of the useful beam enters the patient, unless the high-level control is activated. Special means of activation of high-level controls shall be required. The high-level control shall be operable only when continuous manual activation is provided by the operator. A continuous signal audible to the fluoroscopist shall indicate that the high-level control is being employed. (2) Fluoroscopic equipment that is not provided with AERC shall not be operable at any combination of tube potential and current that will result in an exposure rate in excess of 5 R (1.29 mC/kg) per minute at a point where the center of the useful beam enters the patient, except: (a) During the recording of fluoroscopic images; or (b) When optional high-level control is activated. Special means of activation of high-level controls shall be required. The high-level control shall be operable only when continuous manual activation is provided by the operator. A continuous signal audible to the fluoroscopist shall indicate that the high-level control is being employed. (3) Equipment with both an AERC mode and a manual mode. Fluoroscopic equipment that is provided with both an AERC and a manual mode shall not be operable at any combination of tube potential and current that will result in an exposure rate in excess of 10 R (2.58 mC/kg) per minute in either mode at a point where the center of the useful beam enters the patient, except: (a) During the recording of fluoroscopic images; or (b) When the mode or modes have an optional high-level control, in which case that mode or modes shall not be operable at any combination of tube potential and current that will result in an exposure rate in excess of 5 R (1.29 mC/kg) per minute at a point where the center of the useful beam enters the patient, unless the high-level control is activated. Special means of activation of high-level controls shall be required. The high-level control shall be operable only when continuous manual activation is provided by the operator. A continuous signal audible to the fluoroscopist shall indicate that the high-level control is being employed. (4) Exemptions. Fluoroscopic radiation therapy simulation systems are exempt from the requirements set forth in sections (1), (2), and (3) of this rule. (5) For fluoroscopic equipment manufactured on and after May 19, 1995, the following requirements will apply: (a) Fluoroscopic equipment operable at any combination of tube potential and current that will result in an exposure rate in excess of 5 R (1.29 mC/kg) per minute at a point where the center of the useful beam enters the patient shall be equipped with AERC. Provision for manual selection of the technique factors may be provided. (b) Fluoroscopic equipment shall not be operable at any combination of tube potential and current that will result in an exposure rate in excess of 10 R (2.58 mC/kg) per minute at a point where the center of the useful beam enters the patient except: (A) During the recording of fluoroscopic images from an X-ray image-intensifier tube using photographic film or a video camera when the X-ray source is operated in a pulsed mode. (B) When an optional high-level control is activated, the equipment shall not be operable at any combination of tube potential and current that will result in an exposure rate in excess of 20 R per minute at a point where the center of the useful beam enters the patient. Special means of activation of high-level controls shall be required. The high-level control shall be operable only when continuous manual activation is provided by the operator. A continuous signal audible to the fluoroscopist shall indicate that the high-level control is being employed. (6) Measuring compliance. Compliance with the requirements of this rule shall be determined as follows: (a) Movable grids and compression devices shall be removed from the useful beam during the measurement; (b) If the source is below the table, exposure rate shall be measured 1 cm above the tabletop or cradle; (c) If the source is above the table, the exposure rate shall be measured at 30 cm above the tabletop with the end of the beam-limiting device or spacer positioned as closely as possible to the point of measurement; (d) For a C-arm type of fluoroscope, the exposure rate shall be measured 30 cm from the input surface of the fluoroscopic imaging assembly, with the source positioned at any available SID, provided that the end of the beam-limiting device or spacer is no closer than 30 cm from the input surface of the fluoroscopic imaging assembly; (e) For a lateral type fluoroscope, the exposure rate shall be measured at a point 15 cm from the centerline of the X-ray table and in the direction of the X-ray source with the end of the beam-limiting device or spacer positioned as closely as possible to the point of measurement. If the tabletop is moveable, it shall be positioned as closely as possible to the lateral X-ray source, with the end of the beam-limiting device or spacer no closer than 15 cm to the centerline of the X-ray table. (7) Exemptions. Fluoroscopic radiation therapy simulation systems are exempt from the requirement set forth in section (5) of this rule. (8) Periodic measurement of entrance exposure rate shall be performed as follows: (a) Such measurement shall be made annually or after any maintenance of the system which might affect the exposure rate; and (b) Results of these measurements shall be posted where any fluoroscopist may have ready access to such results while using the fluoroscope and in the record required in OAR 333-106-0105(1)(c). The measurement results shall be stated in roentgens per minute and include the technique factors used in determining such results. The name of the person performing the measurements and the date the measurements were performed shall be included in the results; and (c) Personnel monitoring devices may be used to perform the measurements required by subsection (8)(a) of this rule, provided the measurements are made as described in subsection (8)(d) of this rule; (d) Conditions of periodic measurement of entrance exposure rate are as follows: (A) The measurement shall be made under the conditions that satisfy the requirements of section (6) of this rule; and (B) The kVp shall be the kVp typical of clinical use of the X-ray system; and (C) The X-ray system(s) that incorporates automatic exposure control shall have sufficient material placed in the useful beam to produce a milliamperage typical of the use of the X-ray system or the worst case; and (D) X-ray system(s) that do not incorporate an automatic exposure control shall utilize a milliamperage typical of the clinical use of the X-ray system. NOTE: Materials should be placed in the useful beam when conducting these periodic measurements to protect the imaging system.