Re: Industrial Radiography Accidents - AVOIDENCE IDEAS

[Celia Rajkovich - Radiation Safety <celiar@ANDREW.CMU.EDU>]

Your ideas are great, unfortunately that would require "following a 

procedure". There lies the problem.



--On Wednesday, October 10, 2001 11:14 AM -0500 "Richard, Mack L" 

<mrichar@iupui.edu> wrote:



> Radsafers:

>

> First, please understand that I have limited knowledge/experience with

> industrial radiography.  I've seen the sources/shields (as I recall the

> radiographers referred to these as "cameras") and have a basic

> understanding of how they function.  With that disclaimer out of the way,

> I wonder if some modifications to these cameras might help prevent some

> of these overexposure problems.

>

> It seems that in a number of overexposure cases I've read about, the

> radiographer fails to perform a radiation survey after the source has

> supposedly but unsuccessfully been retracted into the shield.  Whether the

> failure is forgetfulness, negligence, pending tee time, etc., the result

> is the same.  Someone stated that these devices have some type of

> indicator to advise the radiographer of the source position.  While not

> explicitly stated, I assume that to mean either a mechanical or

> electro-mechanical device (i.e., it doesn't actually measure radiation).

>

> Here's a thought on a solution to this problem.  Would it not be possible

> to place some type of detector on the side of the shield where the source

> exits the shield that would be connected to a flashing light to indicate

> the presence of elevated levels of radiation?  One could even configure

> the "on-off" switch so that when the source guide tube is connected, it

> automatically turns the detector on (that prevents the radiographer from

> forgetting to turn on the detector).  Of course, a "threshold" level would

> have to be set to prevent the detector from activating the flashing light

> due to radiation shining through the shield.  Since this would have to be

> a battery powered detector, one would also like to see some type of

> audible or visual warning if the batteries are low.

>

> Granted, as the source is extended away from the shield through the guide

> tube, the detector may quit flashing due to a reduction in radiation

> intensity.  Thus, if the source became detached in the guide tube at some

> distance from the shield, there would be no indication of a problem.

> However, the radiographer would know something was amiss if the light

> didn't begin flashing as he retracted the source back into the shield.

> Given this drawback, such a device shouldn't replace the post irradiation

> survey.

>

> This idea is similar to what we utilize when we perform "high dose rate

> (HDR)" brachytherapy.  HDR brachytherapy involves remotely threading a 10

> Ci Ir-192 source through a catheter (thin plastic "guide" tube for you

> non-medical types) into a specific area of a patient's body (e.g., tumor).

> This is necessarily performed in a shielded room.  Although the HDR

> console indicates the status of the source position, we are required to

> have a separate monitoring system that monitors the radiation in the room

> to independently indicate the presence/absence of radiation in the room.

> At the end of the treatment, we perform a survey with a portable survey

> instrument before we take the patient out of the treatment room.

>

> It seems that such a system might help to prevent these overexposures

> (unfortunately, nothing is 100%).  Perhaps such a system would be cost

> prohibitive or not compatible for the various camera configurations.  As I

> said, my knowledge of industrial radiography is limited and sometimes

> ignorance is bliss.  I won't be offended if someone comes up with a

> laundry list of reasons why this won't work.

>

> Just my 2 cents worth (see, you may have gotten what you paid for).

>

> Regards,

> Mack R.

>

> Mack L. Richard, M.S., C.H.P.

> Radiation Safety Officer - IUPUI/Indiana Univ. Med. Cntr.

> Phone #: (317) 274-0330   Fax #: (317) 274-2332

> E-Mail Address:  mrichar@iupui.edu

>

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