La. Admin. Code tit. 33 § XV-610

Current through Register Vol. 50, No. 11, November 20, 2024

Section XV-610 - Computed Tomography X-Ray Systems

Contrast Scale-Repealed.

CS-Repealed.

CT Conditions of Operation-Repealed.

CT Gantry-Repealed.

CTN-Repealed.

CT Number-Repealed.

Dose Profile-Repealed.

Elemental Area-Repealed.

Multiple Tomogram System-Repealed.

Noise-Repealed.

Nominal Tomographic Section Thickness-Repealed.

Picture Element-Repealed.

Reference Plane-Repealed.

Scan-Repealed.

Scan Increment-Repealed.

Scan Sequence-Repealed.

Scan Time-Repealed.

Single Tomogram System-Repealed.

Tomographic Plane-Repealed.

A. Requirements for CT Equipment

1. Technical and Safety Information. The technical and safety information relating to the conditions of operation, dose information, and imaging performance provided by the CT manufacturer shall be maintained by the facility.

2. Termination of Exposure.

a. Means shall be provided to terminate the X-ray exposure automatically by either de-energizing the X-ray source or shuttering the X-ray beam in the event of equipment failure affecting data collection. Such termination shall occur within an interval that limits the total scan time to no more than 110 percent of its preset value through the use of either a backup timer or devices that monitor equipment function.

b. A visible signal shall indicate when the X-ray exposure has been terminated through the means required by LAC 33:XV.610.A.2.a.

c. The operator shall be able to terminate the X-ray exposure at any time during a scan, or series of scans under CT X-ray system control, of greater than 0.5 second duration.

3. Tomographic Plane Indication and Alignment

a. For any single tomogram system, means shall be provided to permit visual determination of the tomographic plane or a reference plane offset from the tomographic plane.

b. For any multiple tomogram system, means shall be provided to permit visual determination of the location of a reference plane. This reference plane can be offset from the location of the tomographic planes.

c. If a mechanism using a light source is used to satisfy LAC 33:XV.610.A.3.a or b, the light source shall allow visual determination of the location of the tomographic plane or reference plane under ambient light conditions of up to 500 lux.

4. Beam On and Shutter Status Indicators and Control Switches.

a. The CT X-ray control and gantry shall provide visual indication whenever X-rays are produced.

b. Each emergency button or switch shall be clearly labeled as to its function.

5. Indication of CT Conditions of Operation. The 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 a 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.

6. Additional Requirements Applicable to CT X-ray Systems Containing a Gantry Manufactured After September 3, 1985

a. The total error in the indicated location of the tomographic plane or reference plane shall not exceed 5 millimeters.

b. If the X-ray production period is less than 0.5 second, the indication of X-ray production shall be actuated for at least 0.5 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.

c. The deviation of indicated scan increment versus actual increment shall not exceed +1 millimeter with any mass from zero 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 travel.

d. 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.

B. Facility Design Requirements

1. Aural Communication. Provision shall be made for two way aural communication between the patient and the operator at the control panel.

2. Viewing Systems. Provisions shall be made as follows:

a. windows, mirrors, closed-circuit television, or an equivalent shall be provided to permit continuous observation of the patient during irradiation and shall be so located that the operator can observe the patient from the control panel; and

b. when the primary viewing system is by electronic means, an alternate viewing system (which may be electronic) shall be available for use in the event of failure of the primary viewing system.

C. CT Surveys, Performance Evaluations, Routine Quality Control, and Operating Procedures

1. Radiation Protection Surveys

a. All CT X-ray systems installed after February 20, 1991, shall have a radiation protection survey completed by, or under the general supervision of, a qualified expert within 30 days of installation. Existing systems not previously surveyed shall have a survey completed by, or under the general supervision of, a qualified expert. The survey shall be completed in no less than 12 months, and no more than 14 months, from [promulgation date], the effective date of these regulations. In addition, such surveys shall be done after any change in the facility or equipment that might cause a significant increase in radiation hazard.

b. The registrant shall obtain a written report of the survey from the qualified expert, and a copy of the report shall be made available to the department upon request.

2. System Performance Evaluations

a. The testing of the CT X-ray system shall be at intervals of no less than 12 months, and no more than 14 months, performed by, or under the general supervision of, a qualified expert who assumes the responsibility and signs the final performance evaluation report.

b. Evaluation standards and tolerances shall be established by the qualified expert and maintained by the facility. These standards and tolerances shall meet nationally recognized standards and tolerances for the CT X-ray system.

c. The evaluation of a CT X-ray system shall be performed within 30 days after initial installation and at intervals of no less than 12 months, and no more than 14 months thereafter. In addition, the qualified expert shall complete an evaluation of the CT system within 30 days or after any change or replacement of components which, in the opinion of the qualified expert, could cause a change in the radiation output or image quality.

d. The evaluation shall include but not be limited to:

i. geometric factors and alignment including:

(a). alignment light accuracy; and

(b). table increment accuracy;

ii. image localization from scanned projection radiograph (localization image);

iii. radiation beam width;

iv. image quality including:

(a). high-contrast (spatial) resolution;

(b). low-contrast resolution;

(c). image uniformity;

(d). noise; and

(e). artifact evaluation;

v. CT number accuracy;

vi. image quality for acquisition workstation display devices;

vii. a review of the results of the routine QC required under LAC 33:XV.610.C.3;

viii. a safety evaluation of audible and visual signals, posting requirements; and

ix. dosimetry.

e. The measurement of the radiation output of a CT X-ray system shall be performed with a calibrated dosimetry system. The calibration of such system shall be traceable to a national standard. The dosimetry system shall be calibrated per manufacturer recommendations not to exceed two years.

3. Routine Quality Control. A routine QC program on the CT system shall:

a. be developed by a qualified expert and include acceptable tolerances for points evaluated;

b. incorporate the use of a water equivalent phantom. At a minimum, noise, CT number, and artifacts shall be evaluated;

c. be completed at time intervals and under system conditions specified by the qualified expert. The interval shall not exceed one week; and

d. be documented and maintained for inspection by the department.

4. Operating Procedures

a. The operator of the CT X-ray system shall meet the minimum operator requirements of these regulations and be specifically trained on the operational features of the unit by a manufacturer's applications specialist or a qualified expert.

b. The following information shall be readily available to the CT operator:

i. instructions on performing routine QC, including the use of the CT phantom(s), a schedule of routine QC appropriate for the system, allowable variations set by the qualified expert for the indicated parameters, and the results of at least the most recent routine QC completed on the system; and

ii. if the qualified expert evaluation or routine QC of the CT X-ray system identifies that a system operating parameter has exceeded a tolerance established by the qualified expert, use of the CT X-ray system on patients shall be limited to those uses permitted by established written instructions of the qualified expert.

D. CT Radiation Protocol Committee (RPC). The registrant shall develop and maintain an RPC in accordance with the following.

1. Members of the RPC.

a. Members of the RPC shall include but not be limited to the:

i. lead CT radiologist;

ii. lead CT technologist;

iii. qualified expert; and

iv. other individuals as deemed necessary by the registrant (e.g., radiation safety officer, chief medical or administrative officer, radiology department administrator/ manager).

b. If the registrant has more than one site with CT, they may establish a system-wide RPC.

c. Two or more registrants may form a cooperative RPC as long as each facility has a representative on the committee.

d. If the registrant has already established a radiation safety committee, the requirements of this Subsection may be delegated to that committee if the members meet the requirements of LAC 33:XV.610.D.1.

2. Responsibilities of the RPC. The RPC shall:

a. review existing CT protocols along with the evaluation and implementation of new and innovative technologies that can improve image quality and/or lower patient dose in comparison with the older protocol;

b. review the capabilities of the individual CT scanner to ensure maximum performance is achieved;

c. determine and review the protocols used frequently or that could result in significant doses. This review shall include acquisition and reconstruction parameters, image quality, and radiation dose. At a minimum, the facility shall review the following clinical protocols, if performed, at 12 month intervals:

i. pediatric head;

ii. pediatric abdomen;

iii. adult head;

iv. adult abdomen;

v. adult chest; and

vi. brain perfusion;

d. establish and implement written protocols, or protocols documented in an electronic reporting system that include, but are not limited to, the following:

i. a method to be used to monitor the CT radiation output;

ii. a standardized protocol naming policy;

iii. a DRL and alert value for CT procedures reviewed in LAC 33:XV.610.D.2.c. Alert values may be applied by using trigger values in conformance with NEMA XR-29 or facility-established values and procedures as defined by the qualified expert;

iv. actions to be taken for cases when the dose alert value was exceeded which may include patient followup; and

v. a process determining who has access and authority to make changes to the protocol management systems, including a method to prevent inadvertent or unauthorized modifications to a CT protocol;

e. if CT fluoroscopy is performed, the RPC shall establish and implement operating procedures and training designed to minimize patient and occupational radiation exposure;

f. provide a report to the radiation safety committee, or in the absence of a radiation safety committee, the person responsible for radiation safety. Report shall be provided at intervals of no less than 12 months, and no more than 14 months; and

g. at a minimum, the RPC members in LAC 33:XV.610.D.1.a.i-iii shall meet as often as necessary to conduct business, but at 12 month intervals.

3. Records

a. A record of each RPC meeting shall be maintained. The record shall include the date, names of individuals in attendance, minutes of the meeting, and any action taken.

b. The registrant shall maintain a record of the RPC policies and procedures.

c. The registrant shall maintain a record of radiation output information so the radiation dose may be estimated in accordance with established protocols (e.g., SSDE). The record shall include:

i. patient identification;

ii. type and date of examination;

iii. identification of the CT system used; and

iv. the dose values the CT system provides (e.g., CTDI_vol, DLP, SSDE).

E. Reserved.

F. PET CT and SPECT CT Systems. CT systems solely used to calculate attenuation coefficients in nuclear medicine studies shall meet the requirements in Subsections A - D of this Section, unless the following criteria are met.

1. In lieu of LAC 33:XV.610.C.2, a qualified expert shall complete a performance evaluation of the CT system following manufacturer's protocol. The evaluation shall be completed at intervals of no less than 12 months, and no more than 14 months.

2. In lieu of LAC 33:XV.610.C.3, routine QC checks shall be completed at intervals not to exceed one week. These checks shall be established and documented by a qualified expert following manufacturer's protocol.

G. Cone Beam Computed Tomography (CBCT) Systems

1. CBCT facilities shall meet LAC 33:XV.604, 606.B and C, and 610.A.2-6, as applicable.

2. Beam Alignment. The X-ray field in the plane of the image receptor shall not exceed beyond the edge of the image receptor by more than 2 percent of the SID, when the axis of the X-ray beam is perpendicular to the plane of the image receptor. In addition, the center of the X-ray field shall be aligned with the center of the image receptor to within 2 percent of the SID.

3. A performance evaluation shall be performed by, or under the general supervision of, a qualified expert. The evaluation shall follow nationally recognized standards and tolerances. The evaluation shall be performed within 30 days of the initial installation, at intervals of no less than 12 months, and no more than 14 months, and within 30 days after any change or replacement of components which, in the opinion of the qualified expert, could cause a change in the radiation output or image quality. The facility shall maintain documentation of the established standards and tolerances and testing results.

4. The registrant shall follow the quality control recommendations provided by the CBCT manufacturer. In the absence of manufacturer provided quality control recommendations, the registrant shall implement and document quality control guidelines established by the qualified expert in accordance with nationally recognized guidelines.

5. The registrant or radiation protocol committee, if established, shall implement and document a policy addressing deviations from established protocols.

6. The CBCT X-ray system shall only be operated by an individual who has been specifically trained in its operation.

7. The following information shall be readily available to the CBCT operator:

a. instructions on performing routine quality control, including the use of the CBCT phantom(s), a schedule of routine quality control appropriate for the system, allowable variations set by the qualified expert, if required, for the indicated parameters, and the results of at least the most recent routine quality control completed on the system.

8. Exemption. A qualified expert performance evaluation on CBCT systems capable of operating at no greater than 100 kV or 20 mA shall be performed at intervals not to exceed 24 months, or an interval approved by the department.

9. Exemption. The registrant using fluoroscopy systems capable of CBCT shall meet LAC 33:XV.610.G, except LAC 33:XV.610.A.2-6 in LAC 33:XV.610.G.1.

H. Veterinary CT Systems. CT systems, including CBCT systems, solely used in nonhuman imaging shall meet the requirements of LAC 33:XV.610.C.1 (radiation protection surveys) and are otherwise exempt from the standards of LAC 33:XV.610.

La. Admin. Code tit. 33, § XV-610

Promulgated by the Department of Environmental Quality, Nuclear Energy Division, LR 13:569 (October 1987), amended by the Office of Air Quality and Radiation Protection, Radiation Protection Division, LR 19:1421 (November 1993), amended by the Office of Environmental Assessment, Environmental Planning Division, LR 26:2586 (November 2000), Amended by the Office of the Secretary, Legal Affairs and Criminal Investigations Division, LR 482944 (12/1/2022).

AUTHORITY NOTE: Promulgated in accordance with R.S. 30:2001 et seq. and 2104.