Radiation Control (Article 175) - Protective garments

Proposed Rules: Closed to Comments

Comment By: 
Tuesday, October 22, 2013
Download Copy of Proposed Rule (.pdf): 



Statement of Basis and Purpose


ORH regulations for radiation machines and radioactive materials are contained in Article 175 of the Health Code. ORH registers and inspects radiation machines, and licenses and inspects radioactive materials facilities for compliance with Article 175 for the protection of the health and safety of patients, radiation program employees and the general public.


There are about 6500 registered facilities possessing radiation machines and 375 licensed sites in New York City possessing radioactive material for medical, academic and research purposes. Of the registered facilities, approximately 6440 are registered diagnostic X-ray facilities and 60 are therapeutic X-ray facilities possessing certified registrations. ORH inspects these facilities at frequencies of once every 1, 2 or 3 years depending on the type of usage.



I.              Cone Beam Computed Tomography (CBCT)


Cone Beam Computed Tomography (CBCT) units are specialty CT x-ray units that produce radiation levels higher than conventional dental intra-oral x-ray units and are utilized for the imaging of the jaw, specific teeth, and the sinus cavity with high resolution. CBCT is useful for imaging and reconstruction of the human anatomy where speed and accurate reconstruction of structures is essential, but low contrast resolution is not essential. CBCT units were introduced into the dental environment in the early 2000s as an advanced imaging technology for dentists. The dental community has embraced CBCT technology and dental imaging professional organizations have put out position papers on CBCT use in the dental office.


CBCT has the potential to generate radiation exposures outside the range of traditional dental x-ray devices and has increased operational complexity that can result in unintended exposures to the public and workers. The graphic below identifies where the CBCT radiographic units fit in the universe of radiographic units that ORH regulates. The scale below presents the range of exposure in terms of milliamperes (mA) values1 and shows that CBCT units are outside the range found from common dental x-ray devices:


 [see pdf for graphic]


Another measure of comparison for radiographic units is to compare the typical Entrance Skin Exposure (ESE) or entrance patient dose, which are typically interchangeable for diagnostic x-ray kVps. CBCT manufacturer manuals reviewed indicate that the typical range for CBCT entrance dose is in the range of 2 – 4.4 mGy (about 0.2 – 0.44 rads). Data tabulated by the regulatory community in the United Kingdom shows that the effective dose for CBCT units are higher than conventional dental x-ray procedures:


Table: Typical doses from x-ray examinations of the head

Dental Panoramic Exam

Effective Dose (uSv) =

24 micro Sieverts

CBCT Unit (large Field of View)

Effective Dose (uSv) =

68-1073 micro Sieverts

CT Scan Dental Program

Effective Dose (uSv) =

534-2100 micro Sieverts



Currently, there are no standards in Article 175 to regulate CBCTs installed in dental offices. ORH estimates that 90 dental facilities employ CBCT in New York City. Dental facilities possessing such CBCT units will be required to register with and allow inspection by the Department and will need to develop a quality assurance program, which will be composed of periodic quality control testing and a radiation safety manual to ensure patient and operator safety. The proposed regulations are needed to protect both the members of the public undergoing such CBCT exams and operators of the CBCT units.


II.            Operator protective lead garments


Protective lead garments are an important radiation safety tool for radiation facility operators and their workers conducting fluoroscopic2 procedures in order to reduce their occupational radiation exposures. To assure that these lead protective garments retain their integrity over time, these garments should undergo routine testing by a variety of methods, as indicated in these proposed rules. If defective protective garments are used unknowingly, then their users will be subjected to unnecessary radiation exposures.


Currently, there are no standards in Article 175 for the integrity testing of protective lead garments. These proposed rules will provide a uniform standard for testing lead protective garments for registrants of radiation facilities to help ensure that their workers’ occupational radiation exposures can be minimized.


III.           Medical event reporting


The Department seeks to clarify that reporting of a medical event is required not only of radiation materials licensees, but also by radiation equipment registrants. The internal cross-reference provided in the definition of “medical event” is also being revised.




1     The quantity of electron flow (current) in the x-ray tube is described in units of milliamperes (mA). The rate of x-ray production is directly proportional to the x-ray tube current. Higher mA values indicate more electrons are striking the target and therefore producing more x-rays. (Source: http://www.e-radiography.net/radsafety/rad_physics.htm.)


2     Fluoroscopy is a type of medical imaging that shows a continuous x-ray image on a monitor. It is used to diagnose or treat patients by displaying the movement of a body part or of an instrument or dye (contrast agent) through the body. During a fluoroscopy procedure, an x-ray beam is passed through the body. The image is transmitted to a monitor so that the body part and its motion can be seen in detail. (Source: http://www.fda.gov/radiation-emittingproducts/radiationemittingproductsandproceduresmedicalimaging/medicalx-rays/ucm115354.htm)



Public Hearing

Opportunity to comment on proposed amendments of Article 175 (Radiation Control) of the New York City Health Code concerning new requirements for Cone Beam Computed Tomography (CBCT) units in dental facilities; revised requirements for radiation facility personnel protective lead garments and clarification about medical event reporting.

Public Hearing Date: 
Tuesday, October 22, 2013 -
2:00pm to 4:00pm

Roslyn Windholz
42-09 28th Street, 14th Floor, CN31
Long Island City, NY 11101-4132
(347) 396-6078/6116

New York City Department of Health and Mental Hygiene
42-09 28th Street, 14th Floor, Room 14-45
Queens, NY 11101