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Industrial Radiography Accidents
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
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supposedly but unsuccessfully been retracted into the shield.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).
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: email@example.com
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