OAR 333-106-0350
Computed Tomography X-ray Systems: Definitions

In addition to the definitions provided in division 100 and 106 of these rules, the following definitions shall be applicable to OAR 333-106-0350 (Computed Tomography X-ray Systems: Definitions) through 333-106-0369 (Computed Tomography X-ray Systems: Report and Notification of a CT Medical Event).

(1)

“Annual” means a period of 12 consecutive months, not to exceed a period of 14 months.

(2)

“Computed tomography (CT)” means the production of a tomogram by the acquisition and computer processing of X-ray transmission data. Computed tomography includes the capability of producing axial tomograms.

(3)

“Computed Tomography Dose Index” means the integral from -7T to +7T of the dose profile along a line perpendicular to the tomographic plane divided by the product of the nominal tomographic section thickness and the number of tomograms produced in a single scan. This definition assumes that the dose profile is centered around z = 0 and that, for a multiple tomogram system, the scan increment between adjacent scans is nT.

(4)

“Contrast scale” or “CS” means the change in the linear attenuation coefficient per CTN relative to water.

(5)

“CT conditions of operation” means all selectable parameters governing the operation of a CT X-ray system including, but not limited to, nominal tomographic section thickness, filtration, and the technique factors as defined in OAR 333-106-0005 (Definitions).

(6)

“CT gantry” means the tube housing assemblies, beam-limiting devices, detectors, and the supporting structures and frames which hold these components.

(7)

“CT number” means the number used to represent the X-ray attenuation associated with each elemental area of the CT image.

(8)

“CT scanner” means a CT machine capable of performing CT scans of the head, other body parts, or full body patient procedures including PET/CT and SPECT/CT hybrid scanners if used for diagnostic CT procedures.

(9)

“CTDIvol” (see computed tomography dose index).

(10)

CTN (see CT number).

(11)

“Dose-length product (DLP)” is the CTDIvol multiplied by the scan length (image thickness multiplied by the number of adjacent, non-overlapped images in the acquisition in centimeters.

(12)

“Dose profile” means the dose as a function of position along a line.

(13)

“Elemental area” means the smallest area within a tomogram for which the X-ray attenuation properties of a body are depicted (see also picture element.)

(14)

“Multiple tomogram system” means a computed tomography X-ray system which obtains X-ray transmission data simultaneously during a single scan to produce more than one tomogram.

(15)

“Noise” means the standard deviation of the fluctuations in CTN expressed as a percentage of the attenuation coefficient of water.

(16)

“Nominal tomographic section thickness” means the full width at half-maximum of the sensitivity profile taken at the center of the cross-sectional volume over which X-ray transmission data are collected.

(17)

“Picture element” means an elemental area of a tomogram.

(18)

“Positron emission tomography (PET)” means an imaging technique that uses positron-emitting radionuclides to produce 3-dimensional images of functional processes in the body.

(19)

“Qualified CT medical physicist” means an individual qualified in accordance with OAR 333-106-0367 (Computed Tomography X-ray Systems: Records and Report Retention).

(20)

“Reference plane” means a plane which is displaced from and parallel to the tomographic plane.

(21)

“Scan” means the complete process of collecting X-ray transmission data for the production of a tomogram. Data can be collected simultaneously during a single scan for the production of one or more tomograms.

(22)

“Scan increment” means the amount of relative displacement of the patient with respect to the CT X-ray system between successive scans measured along the direction of such displacement.

(23)

“Scan sequence” means a preselected set of two or more scans performed consecutively under preselected CT conditions of operation.

(24)

“Scan time” means the period of time between the beginning and end of X-ray transmission data accumulation for a single scan.

(25)

“Single photon emission computed tomography (SPECT)” means an imaging technique that uses radionuclides to produce 3-dimensional images of functional processes in the body.

(26)

“Single Tomogram System” means a CT X-ray system which obtains X-ray transmission data during a scan to produce a single tomogram.

(27)

“Tomogram” means the depiction of the attenuation properties of a section through a body.

(28)

“Tomographic plane” means that geometric plane which is identified as corresponding to the output tomogram.

(29)

“Tomographic section” means the volume of an object whose X-ray attenuation properties are imaged in a tomogram.

(30)

“Traceable to a national standard” means an instrument is calibrated at either the National Institute of Standards and Technology (NIST) or at a calibration laboratory that participates in a proficiency program with the NIST at least once every two years and the results of the proficiency test conducted within 24 months of calibration show agreement within plus or minus three percent of the national standard in the appropriate energy range.

Source: Rule 333-106-0350 — Computed Tomography X-ray Systems: Definitions, https://secure.­sos.­state.­or.­us/oard/view.­action?ruleNumber=333-106-0350.

333‑106‑0001
Purpose and Scope 333‑106‑0005
Definitions 333‑106‑0010
Administrative Controls 333‑106‑0015
General Requirements: Technique Chart 333‑106‑0020
General Requirements: Written Rules and Procedures 333‑106‑0025
General Requirements: Protection of Patients and Personnel 333‑106‑0035
General Requirements: Deliberate Exposures Restricted 333‑106‑0040
General Requirements: Patient Holding and Restraint 333‑106‑0045
General Requirements: Use of Best Procedures and Equipment 333‑106‑0050
General Requirements: Personnel Monitoring 333‑106‑0055
General Requirements: X-ray Operator Training 333‑106‑0060
General Requirements: Radiation Use and Safety Instructor Qualifications 333‑106‑0101
General Requirements: Diagnostic X-ray Systems 333‑106‑0105
General Requirements: Information and Maintenance Record and Associated Information 333‑106‑0110
General Requirements: Plan Review 333‑106‑0120
General Requirements: Information on Radiation Shielding for Plan Reviews — Optional 333‑106‑0130
General Requirements: Design Requirements for an Operator’s Booth 333‑106‑0201
Fluoroscopic X-ray Systems 333‑106‑0205
Fluoroscopic X-ray Systems Requirements: Activation of the Fluoroscopic Tube 333‑106‑0210
Fluoroscopic X-ray Systems Requirements: Fluoroscopic Entrance Exposure Rates 333‑106‑0215
Fluoroscopic X-ray Systems Requirements: Fluoroscopic Barrier Transmitted Radiation Rate Limits 333‑106‑0220
Fluoroscopic X-ray Systems Requirements: Fluoroscopic Indication of Potential and Current 333‑106‑0225
Fluoroscopic X-ray Systems Requirements: Fluoroscopic Source-to-Skin Distance 333‑106‑0230
Fluoroscopic X-ray Systems Requirements: Fluoroscopic Timer 333‑106‑0235
Fluoroscopic X-ray Systems Requirements: Mobile Fluoroscopes 333‑106‑0240
Fluoroscopic X-ray Systems Requirements: Fluoroscopic Control of Scattered Radiation 333‑106‑0245
Fluoroscopic X-ray Systems Requirements: Fluoroscopic Radiation Therapy Simulation Systems 333‑106‑0301
Additional Requirements for Radiographic Machines: Beam Limitation for Radiographic Systems Other Than Fluoroscopic, Dental Intraoral, Veterinary Systems, or Computed Tomography(CT) 333‑106‑0305
Additional Requirements for Radiographic Machines: Radiation Exposure Control Devices 333‑106‑0310
Additional Requirements for Radiographic Machines: Source-to-Skin Distance 333‑106‑0315
Additional Requirements for Radiographic Machines: Exposure Reproducibility 333‑106‑0320
Additional Requirements for Radiographic Machines: Radiation from Capacitor Energy Storage Equipment in Standby Status 333‑106‑0325
Additional Requirements for Radiographic Machines: Intraoral Dental Radiographic Systems 333‑106‑0345
Purpose and Scope 333‑106‑0350
Computed Tomography X-ray Systems: Definitions 333‑106‑0355
CT Equipment Requirements 333‑106‑0360
Computed Tomography X-ray Systems: Facility Design Requirements 333‑106‑0361
Computed Tomography X-ray Systems: Radiation Protection Surveys 333‑106‑0362
Computed Tomography X-ray Systems: Operating Procedures and Conditions of Operation 333‑106‑0363
Computed Tomography X-ray Systems: Quality Control Program 333‑106‑0364
Computed Tomography X-ray Systems: Initial and Annual Qualified CT Medical Physicist Scanner Performance Evaluations 333‑106‑0366
Computed Tomography X-ray Systems: Dose Limits 333‑106‑0367
Computed Tomography X-ray Systems: Records and Report Retention 333‑106‑0368
Computed Tomography X-ray Systems: Qualified CT Medical Physicist 333‑106‑0369
Computed Tomography X-ray Systems: Report and Notification of a CT Medical Event 333‑106‑0370
Computed Tomography X-ray Systems: Operator Requirements 333‑106‑0601
Veterinary X-ray Systems: Veterinary Medicine Radiographic Installations Additional Requirements 333‑106‑0700
Mammography Requirements: Mammography X-Ray Systems Definitions 333‑106‑0710
Mammography Requirements: Equipment Standards 333‑106‑0720
Mammography Requirements: Quality Assurance Program 333‑106‑0730
Mammography Requirements: Additional Requirements 333‑106‑0735
Mammography Requirements: Breast Density Notification 333‑106‑0750
Mammography Requirements: Mammography Personnel Qualifications
Last Updated

Jun. 8, 2021

Rule 333-106-0350’s source at or​.us