RE: Definition of an X-ray Cabinet

["Kraus, George W." <GWK@CDRH.FDA.GOV>]

Hi,

Please send your email to attention of Dan Kassiday, Engineer for FDA's
Center for Devices and Radiological Health. (CDRH).  He'll be glad to answer
your inquiry.  Dan's email is

  		dfk@cdrh.fda.gov

George Kraus

	-----Original Message-----
	From:	james.g.barnes@att.net [SMTP:james.g.barnes@att.net]
	Sent:	Thursday, October 19, 2000 8:45 PM
	To:	Multiple recipients of list
	Subject:	Definition of an X-ray Cabinet

	Good afternoon,

	Need some thoughts regarding the interpretation of an FDA 
	regulation regarding cabinet X-ray systems.

	Following is the definition of a cabinet X-ray system 
	from 21 CFR 1020.40:

	"(3) Cabinet x-ray system means an x-ray system with the 
	x-ray tube installed in an enclosure (hereinafter
	termed cabinet) which, independently of existing 
	architectural structures except the floor on which it may 
	be placed, is intended to contain at least that portion 
	of a material being irradiated, provide radiation 
	attenuation, and exclude personnel from its interior
	during generation of x radiation. Included are all x-ray 
	systems designed primarily for the inspection of carry-on
	baggage at airline, railroad, and bus terminals, and in 
	similar facilities."

	My question regards the interpretation of the phrase 
	"independently of existing architectural structures 
	except the floor."  There are cabinets that are table-top 
	devices, or "free standing" walk-in units that sit on the 
	floor, but are not really attached to the building 
	structure (i.e, not intended to be part of a building's 
	structure, clearly separate from the rest of the 
	building's structure; not considered a "room" in the 
	building, etc.).  These clearly exist independently of 
	the building structures, and would be considered 
	cabinets.

	However, there are situations where one has built an 
	x-ray cell where the room is permanently built into a 
	facility (i.e., permanently anchored to the floor, not 
	amenable to dismantlment and movement, considered a 
	"room" in the building, etc.), but doesn't structurally 
	"attach" itself to the walls or ceiling of the 
	overall facility (for example, a permanent two-story tall 
	x-ray cell in a four-story warehouse).  I have recently 
	heard it argued that this type of cell construction (as 
	it uses a "stand alone" construction style supported only 
	by the floor) is a "cabinet" under the definition above, 
	and that the construction or modification such a facility 
	would fall under 21 CFR 1020-40.

	This sounds like a very strained interpretation of the 
	regulations.  Does anyone know of further materials that 
	would clarify the intent of the definition?


	Thanks,

	Jim Barnes, CHP
	Radiation Safety Officer
	Rocketdyne/Boeing
	james.g.barnes@boeing.com
	
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