Tomographic plane indication and alignment.
A computed tomography x-ray system shall meet all of the following plane indication and alignment requirements, as applicable:
A single tomogram system shall allow for visual determination of the tomographic plane or a reference plane offset from the tomographic plane.
A multiple tomogram system shall allow for visual determination of the location of a reference plane.
DHS 157.80 Note
Note: The reference plane may be offset from the location of the tomographic planes.
If a device using a light source is used to satisfy the requirements in subd. 2.
, the light source shall provide illumination levels sufficient to permit visual determination of the location of the tomographic plane or reference plane under ambient light conditions of up to 500 lux.
Beam-on and shutter status indicators and control switches. DHS 157.80(1)(c)1.1.
The CT x-ray control and gantry shall provide visual indication whenever x-rays are produced and, if applicable, whether the shutter is open or closed. Each emergency button or switch shall be clearly labeled as to its function.
For systems that allow high voltage to be applied to the x-ray tube continuously and that control the emission of x-ray with a shutter, the radiation emitted may not exceed 0.88 mGy (100 mRem) in one hour at any point 5 cm outside the external surface of the housing of the scanning mechanism when the shutter is closed.
Compliance shall be determined by measurements averaged over an area of 100 square cm with no linear dimension greater than 20 cm.
Indication of CT conditions of operation.
A CT x-ray system shall be designed such that the CT conditions of operation to be used during a scan or a scan sequence shall be indicated prior to the initiation of the scan or a scan sequence. On equipment having all or some of these conditions of operation at fixed values, this requirement may be met by permanent markings. Indication of CT conditions of operation shall be visible from any position from which scan initiation is possible.
Maximum surface CTDI100 identification.
The angular position where the maximum surface CTDI100 occurs shall be identified to allow for reproducible positioning of a CT dosimetry phantom.
CT x-ray systems containing a gantry manufactured after September 3, 1985.
A computed tomography x-ray system containing a gantry that was manufactured after September 3, 1985, shall meet all the following requirements:
The total error in the indicated location of the tomographic plane or reference plane may not exceed 5 millimeters.
If the x-ray production period is less than one-half second, the indication of x-ray production shall be actuated for at least one-half second. Indicators at or near the gantry shall be discernible from any point external to the patient opening where insertion of any part of the human body into the primary beam is possible.
The deviation of indicated scan increment versus actual increment may not exceed plus or minus one millimeter with any mass from 0 to 100 kilograms resting on the support device. The patient support device shall be incremented from a typical starting position to the maximum incremented distance or 30 centimeters, whichever is less, and then returned to the starting position. Measurement of actual versus indicated scan increment may be taken anywhere along this patient support device movement distance.
Premature termination of the x-ray exposure by the operator shall necessitate resetting of the CT conditions of operation prior to the initiation of another scan.
A CT x-ray system for human use may only be operated for diagnostic procedures by an American registry of radiologic technologists certified person who has been specifically trained in its operation.
A CT x-ray system for veterinary use may only be operated for diagnostic procedures by a person who is certified by the American registry of radiological technologists or has completed training equivalent to the requirements of Appendix L and has been specifically trained in its operation.
Combination systems which combine CT with another imaging device that uses radioactive material shall be operated by a person qualified by training in the safe use of radioactive materials and who meets the training requirements of Appendix L.
Information shall be available at the control panel regarding the operation and calibration of the system. The information shall include all of the following components:
Dates of the latest calibration and spot checks and the location within the facility where the results of those tests may be obtained.
Instructions on the use of the CT dosimetry phantom including a schedule of spot checks appropriate for the system, allowable variations for the indicated parameters and the results of at least the most recent spot checks conducted on the system.
The distance in millimeters between the tomographic plane and the reference plane if a reference plane is utilized.
A current technique chart available at the control panel, which specifies for each routine examination the CT conditions of operation and the number of scans per examination including body part size and correct kV/mA for that body part. The technique chart shall be used to adjust techniques based on the body part being examined.
Calibration and spot check measurements shall be made at a frequency recommended by the manufacturer. If the calibration or spot check of the CT x-ray system identifies that a system operating parameter has exceeded a tolerance established by the medical physicist, use of the CT x-ray system on patients shall be limited to those uses permitted by established written instructions of the medical physicist.
A facility shall follow the manufacturer's daily start up routines and preventative maintenance schedules for a specific computed tomography x-ray system.
DHS 157.80 History
History: CR 01-108
: cr. Register July 2002 No. 559
, eff. 8-1-02; CR 06-021
: renum. (1) (a) and (c) to be (1) (a) 1. and (c) 1., cr. (1) (a) 2. and 3. and (c) 2. and 3., am. (2) (a) Register October 2006 No. 610
, eff. 11-1-06; CR 09-062
: renum. (2) (a) to be (2) (a) 1. and 3. and am., cr. (2) (a) 2. Register April 2010 No. 652
, eff. 5-1-10.
Plan review and approval.
Prior to construction, the floor plans, shielding specifications and equipment arrangement of all new installations, or modifications of existing installations, utilizing ionizing radiation machines, including dental CT and dental cephalometric machines, shall be submitted to the department for review and approval.
DHS 157.81 Note
Note: Plans may be mailed to the department at: Department of Health Services, Radiation Protection Section, P.O. Box 2659, Madison WI 53701-2659 or package delivery to: Department of Health Services, Radiation Protection Section, Room 150, 1 West Wilson St, Madison WI 53702-0007.
Dental intraoral and panoramic, mammography, and bone density devices are exempt from this section.
A shielding plan for a facility with two or more x-ray rooms shall include a medical physicist or person approved by a medical physicist recommendation for shielding.
A shielding plan submitted for department review shall include all of the following:
A scale drawing of the room in which a stationary radiation machine system is located with such drawing indicating the use of areas adjacent to the room and an estimation of the extent of occupancy by a person in such areas. In addition, the drawing shall include all of the following:
The type and thickness of materials, or lead equivalency, of each protective barrier.
The use and occupancy of the areas surrounding an x-ray room, including occupied areas above or below an x-ray room.
The operator booth described in the shielding plan shall be designed to meet all the following requirements:
The view area of the window shall be at least 0.09 m2 (144 square inches).
The window shall be placed so that the edge of the view window is at least 0.45 meters (18 inches) from the end of the barrier. The window shall be placed so that the patient may be observed at all times and each entrance to the room is observed from the operator position. Patient and entrance observation may be accomplished by the use of electronic devices or mirrors.
The shielding value of the window shall be equal to the wall in which it is mounted.
Booth walls shall be 2.1 meters (7 feet) in height and permanently attached to the floor or walls. The booth shall be at least 1.3 meters (4 feet) from the nearest vertical cassette holder or 0.3 meters (one foot) from the nearest corner of the examining table.
When a door or moveable panel is used as an integral part of the booth structure, it shall have a permissive device that prevents an exposure when the door or panel is not closed.
Verbal communication with the patient shall be possible at all times during the x-ray procedure.
The x-ray exposure control shall be located within the shielded area and at least 1 meter (3.3 feet) from the open end of the protective barrier, excluding mammography units.
(4) Operational analysis.
The department may require additional modifications to a shielding plan after initial approval of the plan if a subsequent analysis of operating conditions indicates the possibility of a person receiving a dose in excess of the limits prescribed in ss. DHS 157.22 (1)
and 157.23 (1)
. An existing x-ray room constructed using 5 mSv (500 mR) as the public exposure limit may continue to operate without modification until the x-ray equipment is replaced or the room is modified.
DHS 157.81 History
History: CR 01-108
: cr. Register July 2002 No. 559
, eff. 8-1-02; CR 06-021
: am. (3) (a) Register October 2006 No. 610
, eff. 11-1-06; CR 09-062
: am. (1) and (2), cr. (3) (c) 7. Register April 2010 No. 652
, eff. 5-1-10.
General administrative requirements for facilities using therapeutic radiation machines for human use. DHS 157.82(1)(1)
A registrant shall be responsible for directing the operation of the therapeutic radiation machines that have been registered with the department. All persons operating a therapeutic radiation machine shall be instructed in and shall comply with the provisions of the radiation safety requirements of ss. DHS 157.22 (1)
and 157.25 (2)
. A therapeutic radiation machine that does not meet the provisions of this subchapter but is of a type accepted by the US food and drug administration may not be used for irradiation of human patients.
A registrant for any therapeutic radiation machine, except dermatology units under 150 kV, shall require the authorized user to be a physician who meets any of the following requirements:
Radiology, with specialization in radiotherapy, as a British "Fellow of the Faculty of Radiology" or "Fellow of the Royal College of Radiology".
Therapeutic radiology by the Canadian royal college of physicians and surgeons.
Actively practices therapeutic radiology and has completed all of the following:
Two hundred hours of instruction in basic radiation techniques applicable to the use of an external beam radiation therapy unit.
A minimum of 3 years of supervised clinical experience or 5 years of post graduate clinical experience in therapeutic radiology.
Has equivalent training and submits the training of the prospective user physician for department review on a case-by-case basis.
A dermatologist using x-ray units under 150 kV shall be board certified in dermatology or have 40 hours of instruction and 100 hours of supervised therapeutic work using x-ray units for the treatment of skin diseases.
A registrant for electronic brachytherapy shall require the authorized user to complete device specific instruction from the manufacturer or individual trained by the manufacturer, and training on procedures required by s. DHS 157.85 (16) (g) 4.
(3) Visiting users.
A registrant may permit any physician qualified under sub. (2)
to act as a visiting user under the term of the registrant's registration for up to 60 days per year under all the following conditions:
The visiting user has the prior written permission of the registrant's management and if the use occurs on behalf of an institution, the institution's radiation safety committee.
The registrant maintains copies of all records documenting the qualifications of the visiting user for 3 years from the date of the last visit.
The services of a medical physicist is required in facilities having one or more therapeutic radiation machines.
The registrant for any therapeutic radiation machine shall require the medical physicist to have any of the following:
Certification by the American board of radiology in one or more of the following:
Certification by the American board of medical physics in radiation oncology physics.
A master's or doctor's degree in physics, biophysics, radiological physics or health physics and have completed one year of full-time training in therapeutic radiological physics and one year of full-time work experience under the supervision of a medical physicist at a medical institution. A person qualifying under this subdivision shall work under the supervision of a medical physicist qualified under subd. 1.
A registrant employing a physicist who qualifies under this subdivision shall provide the department with a statement of training and experience, signed by the preceptor medical physicist or provide a letter from another state accepting the person as a therapeutic medical physicist.
The medical physicist shall be responsible for all of the following:
Beam data acquisition and transfer for computerized dosimetry and supervision of its use.
Consultation with the physician user in treatment planning, as needed.
Performance of calculations and assessments regarding medical events.