Specific Requirements for Dental Facilities.
24 RCNY § 175.49
in effect§ 175.49 Specific Requirements for Dental Facilities.
(a) The following specific quality assurance requirements apply to a dental facility:
(1) If using a filmless system, maintain and operate PSP and DDR systems according to manufacturer specifications.
(2) The registrant must provide initial training and annual evaluations of x-ray operators to include but not limited to: positioning of the x-ray tube, image processing, operator location during x-ray exposure, source to skin distance, radiation protection, appropriate radiographic protocol and applicable regulatory requirements. Records of training and annual evaluations must be maintained for inspection by the Department.
(b) Warning label.
(1) On systems manufactured on or before June 10, 2006, the control panel containing the main power switch must bear the following warning statement, or the warning statement in paragraph (2) of this subdivision, legible and accessible to view: "WARNING: This x-ray unit may be dangerous to patient and operator unless safe exposure factors and operating instructions are observed."
(2) On systems manufactured after June 10, 2006, the control panel containing the main power switch must bear the warning statement, legible and accessible to view: "WARNING: This x-ray unit may be dangerous to patient and operator unless safe exposure factors, operating instructions and maintenance schedules are observed."
(c) Radiation exposure control. Means must be provided to initiate the radiation exposure by a deliberate action on the part of the operator, such as the depression of a switch. Radiation exposure must not be initiated without such an action.
(d) Exposure control location and operator protection. Except for units designed to be hand-held, the exposure control must allow the operator to be:
(1) behind a protective barrier at least 2 meters (6.5 feet) tall, or
(2) at least 2 meters (6.5 feet) from the tube housing assembly, outside the path of the useful x-ray beam, while making exposures.
(e) Administrative controls.
(1) Patient and image receptor holding devices must be used when the techniques permit.
(2) Except for units designed to be hand-held, the tube housing and position indicating device (PID) must not be hand-held during an exposure.
(f) Hand-held intraoral equipment. In addition to other requirements in this Article, the following applies specifically to hand-held devices:
(1) The hand-held x-ray system must be equipped with a backscatter shield of not less than 0.25 mm lead equivalent and 15.2 cm (6 inches) in diameter that is positioned as close as practicable to the distal end of the position indication device.
(2) The facility must maintain documentation that each operator has completed training as specified by the manufacturer.
(3) The facility must adopt and follow protocols provided by the manufacturer, and approved by the Department, regarding the safe operation of the device.
(4) When operating a hand-held intraoral dental radiographic unit, operators must wear a 0.25 mm lead equivalent apron.
(5) If the operator has difficulty in holding the device stationary during the exposure, the operator shall use a stand to immobilize the device.
(6) The registrant must secure the hand-held device from unauthorized removal or use.
(g) Beam-on indicators. The x-ray control must provide visual indication whenever x- rays are produced. In addition, for certified x-ray units, a signal audible to the operator must indicate that the exposure has terminated.
(h) Multiple tubes. Where two or more radiographic tubes are controlled by one exposure switch, the tube which has been selected must be clearly indicated prior to initiation of the exposure. Only the selected tube can be energized. This indication must be both on the x-ray control panel and at or near the tube housing assembly which has been selected.
(i) Mechanical support of tube head. The tube housing assembly supports must be adjusted such that the tube housing assembly will remain stable during an exposure unless tube housing movement is a designed function of the x-ray system.
(j) Battery charge indicator. On battery-powered generators, visual means must be provided on the control panel to indicate whether the battery is in a state of charge adequate for proper operation.
(k) Technique indicators.
(1) For x-ray equipment capable of displaying technique factors, the technique factors to be used during an exposure must be indicated before the exposure begins.
(2) The requirement of paragraph (1) of this subdivision may be met by permanent markings on equipment having fixed technique factors.
(l) Exposure reproducibility. For any specific combination of selected technique factors, the estimated coefficient of variation of the air kerma must be no greater than 0.05.
(m) Timers. Means must be provided to terminate the exposure at a preset time interval, a preset product of current and time, a preset number of pulses, or a preset radiation exposure to the image receptor.
(n) Kilovolt peak. At a minimum, the kVp must be accurate to within 10 percent on variable kVp units and within 20 percent on fixed kVp units.
(o) X-ray beam alignment.
(1) The useful x-ray beam must be limited to the area of clinical interest.
(2) Intraoral dental units.
(i) X-ray systems designed for use with an intraoral image receptor must be provided with means to limit the source-to-skin distance (SSD) to not less than 18 cm.
(ii) The x-ray field at the minimum SSD must be containable in a circle having a diameter of no more than 7 cm.
(3) Extraoral, panoramic and cephalometric units. X-ray systems designed for use with extraoral image receptors and when used with an extraoral image receptor, must be provided with means to limit the x-ray field in the plane of the image receptor so that such field does not exceed each dimension 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, means must be provided to align the center of the x-ray field with the center of the image receptor to within 2 percent of the SID, or means must be provided to both size and align the x-ray field such that the x-ray field at the plane of the image receptor does not extend beyond any edge of the image receptor. These requirements may be met with:
(i) An assortment of removable, fixed-aperture, beam-limiting devices sufficient to meet the requirement for each combination of image receptor size and SID for which the unit is designed. Each such device must have clear and permanent markings to indicate the image receptor size and SID for which it is designed; or
(ii) A beam-limiting device having multiple fixed apertures sufficient to meet the requirement for each combination of image receptor size and SID for which the unit is designed. Permanent, clearly legible markings must indicate the image receptor size and SID for which each aperture is designed and must indicate which aperture is in position for use.
(p) Beam quality. The Half Value Layer (HVL) of the useful beam for a given x-ray tube potential must not be less than the values shown in Table 1 of 24 RCNY Health Code § 175.47(u). If it is necessary to determine such half-value layer at an x-ray tube potential which is not listed in Table 1, linear interpolation or extrapolation may be made.
(q) Conditions of use.
(1) The x-ray system must always be operated in such a manner that the useful beam at the patient's skin does not exceed the requirements of paragraph (2) of subdivision (o) of this section.
(2) The operator shall position the end of the position indicating device (PID) within 1 cm (0.4 in.) of the skin of the patient, if such device is routinely used in conducting dental radiography.
(3) Time-temperature techniques or automatic processing must be used to develop pre-operative diagnostic dental x-ray films. Processing techniques must be consistent with those recommended by the x-ray film manufacturer. Sight developing of dental radiographs is prohibited except for films taken during operative procedures.
(4) Dental x-ray exposure technique factors and dental processing conditions must yield entrance skin exposure (ESE) values for the bitewing x-ray projection that are identical to or do not exceed the maximum range of ESE values for dental "D" and "E" speed film designations as published in HHS document #FDA-85-8245 (August 1985) or superseding documents. With respect to maximum ESE values for digital image receptors (are deemed to be either Computed Radiography (CR) or Digital Image Receptors (DR)), digital image receptors shall be deemed to be equivalent to "E" speed film.
(r) Facilities possessing a Cone Beam Computed Tomography (CBCT) unit.
(1) Notwithstanding anything in this Article to the contrary, dental facilities possessing a CBCT unit must develop and maintain a written quality assurance program, including a written QA manual and a written radiation safety policy and procedures manual for all CBCT dental equipment possessed by the facility.
(i) For all dental CBCT units, the registrant must establish annual QA testing of x-ray parameters sufficient to maintain patient doses and image quality consistent over time. The annual tests will evaluate, at a minimum, collimation, filtration, patient dose, accuracy and reproducibility of x-ray techniques and the operational status of x-ray safety features.
(ii) For all CBCT units, the QA tests must follow the manufacturer's recommended tests and frequency and utilize the manufacturer's QA phantom. The QA test results will be retained for review by the Department for 5 years, the facility must establish QA testing that includes, at a minimum, the manufacturer's recommended QA tests plus the additional QA tests described in subparagraph (iii) of this subdivision.
(iii) Semi-annual QA tests to determine image noise, image uniformity, reconstructed image measurement accuracy, high contrast spatial resolution of the CBCT unit.
(iv) Dental facilities possessing a CBCT unit must use a medical physicist who is a QMP in performing its QA activities.
(2) Dental facilities possessing CBCT equipment must annually determine the patient radiation dose (using direct measurement or indirect means to estimate dose) for the most common CBCT scan used at the facility as conducted by a QMP.
(3) Dental facilities possessing CBCT equipment must conduct annual QA tests to measure reproducibility of imaging parameters (kVp, exposure time and dimensions of the scan beam), reproducibility of exposure per the most common scan and beam filtration (HVL).
(4) Conditions of operation for the CBCT unit.
(i) Facilities possessing a CBCT unit must adhere to the requirements of sections 24 RCNY Health Code §§ 175.46 and 175.47 regarding the shielding requirements and operator protection for all CBCT units possessed by the dental facility.
(ii) All operators of the CBCT must undergo training on the proper operation of the CBCT units and documentation of this training must be retained by the dental facility for review by the Department until after the next scheduled inspection is completed by the Department.
(iii) All operators must be able to communicate with and visually observe the patient during the CBCT examination from the operator's protected position.
(iv) CBCT patient exams will not be conducted solely for cosmetic purposes with no diagnostic value to the patient.
(v) The logbook for CBCT exams must contain all relevant diagnostic examination information, including but not limited to, x-ray technique, scan time, anatomical exam site and reason for examination.
(Added City Record 4/24/2019, eff. 5/24/2019)
Source: City of New York, Charter, Administrative Code and Rules (American Legal Publishing XML export, codelibrary.amlegal.com)URL: https://codelibrary.amlegal.com/codes/newyorkcity/latest/NYCrules/0-0-0-117425Fetched: 10/24/2026