[ RadSafe ] X-Ray On Lights

[North, David]

As far as I know, the practice of mounting lights such as you describe
outside x-ray rooms is just that: a practice. But I am always willing to be
further educated. Another practice which nowadays is generally discouraged
is linking an exposure interrupter to the door. The idea is to prevent
someone from becoming inadvertently exposed if he/she opens the door during
a radiographic or fluoroscopic procedure. The problem is that while you may
prevent a tiny dose to the door-opener, you have interfered with an x-ray
exam and possibly necessitated additional (much greater) dose to the poor
patient.

I can't see why a DEXA scanner would ever need such a light because the
stray radiation levels from those units are so low that the tech can sit in
the room right next to the scanning couch all day and not even come close to
any reasonable ALARA limit.

An "X-RAY ON" light outside the SPECT/CT ROOM is a reasonable idea just for
the fact that there is a CT scanner in the room. The door shouldn't be
locked in case the patient tanks and a code team needs to get in there
quickly.

David L. North, Sc.M., DABR
Associate Physicist
Medical Physics
Main Bldg. Rm 317
Rhode Island Hospital
593 Eddy St.
Providence, RI 02903
(401)444-5961
fax: (401)444-4446
dnorth at lifespan.org





> ----------
> From: 	radsafe-bounces at radlab.nl on behalf of Vernig, Peter G.
> Sent: 	Friday, June 10, 2005 11:39
> To: 	radsafe at radlab.nl
> Subject: 	[ RadSafe ] X-Ray On Lights
> 
> If I might interrupt the debate about the toxicity and morality of DU and
> the educational backgrounds of the participants I have a real question
> that
> somebody on Radsafe might just help me with.
> 
> All of our fixed x-ray rooms including the cath labs have lights that say
> X-Ray on and light up either when the rotor of a radiographic unit is
> spinning [for those of you not familiar with medical diagnostic x-rays the
> anode rotates to dissipate heat generated when the electrons  strike the
> anode and usually the rotor spins in anticipation of the actual burst of
> electrons.] or when fluoro units are producing x-rays.
> 
> It seems that most if not all of the other VAs have a variation on this.
> Wording may differ, one facility the light just goes on during x-rays so
> that unless you stare at it, you'd miss it for radiographic units.
> 
> My question is does anybody know the origin of this.  A reg, rule, or
> standard or best practice?
> 
> The reason I ask is technology is expanding and we have a DEXA [dual
> energy
> x-ray analyzer] for bone densitometry which produces say 10% of less of
> the
> x-rays that a normal radiographic unit puts out and we are getting a
> hybrid
> SPECT/CT unit.  The DEXA doesn't have such a light and we are tentatively
> planning on putting a light on the SPECT/CT.  But if there is a standard
> or
> recommendation or some such it would be nice to know just what it says.
> BTW
> SPECT = single photon emission computed tomography, a type of gamma
> camera.
>