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How Safe is Your Hospital’s CT Scanner?

Posted November 12, 2010 7:00 AM by Steve Melito

Computed tomography (CT) scanners use X-ray equipment and special computers to produce cross-sectional images of the human body. CAT scans, as they are sometimes called, are non-invasive medical tests that enable doctors to diagnose conditions such as elevated blood flow to a patient's brain.

Recently, the U.S. Food and Drug Administration (FDA) concluded a lengthy multi-state investigation of alleged "radiation overdoses" from CT scanners. The agency concluded that "when properly used", the medical equipment did not malfunction. "Instead," the FDA asserted, "it is likely the improper use of the scanners resulted in these overdoes."

As medical technology increases in complexity, do hospitals need to do more to ensure that personnel receive proper training?

Source: U.S FDA

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Guru
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#1

Re: How Safe is Your Hospital’s CT Scanner?

11/12/2010 10:49 PM

While CT Scanner in proper use is clinically helpful tool, it is true that no one is informed in writing, about quantity of radiation was givin to the person in the process of clinical examination. Some CT examinations take very long time and obviously very high dose of harmful x-rays one gets but no record is maintained.

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#2

Re: How Safe is Your Hospital’s CT Scanner?

11/13/2010 12:28 AM

In a hospital it is statutory requirement that before a CAT machines is commissioned a qualified person certifies after conducting the radiation leak tests as per the prescribed standards. Radiation tests to be carried out regularly as per the laid down policy of the organization. Besides persons who operate CT scan machines should be qualified and need to update their expertise through CME program. Medical doctors who prescribe CT scan test should also prescribe it if it is really required. Ethics and professional values in Medical profession play vital role to reduce unethical practice in diagnosing a patient.

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#3
In reply to #2

Re: How Safe is Your Hospital’s CT Scanner?

11/13/2010 12:38 AM

Qualified Physicist? BARC gives training for handily 10 people per year and on an average 9 of them leave India to find job in USA. You think that one person can handle thousands of hospitals. They have no qualified people and I have never seen a doctor ever visiting the CT Scanner. It is left to untrained unqualified people.

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Guru

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#4

Re: How Safe is Your Hospital’s CT Scanner?

11/13/2010 4:24 AM

Actually I believe the article is talking about over exposure in countries like the US. It is a big topic at present.

Typically you can't have a CT scan and go back to work at a nuclear plant - from what I read - all the bells and sirens start to go off as the instruments consider that you are contaminated.

Fancy scans are often used by the doctor to cover their backside from suits as well as often being demanded by patients that have little or no idea of what the machines are or can do.

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#5
In reply to #4

Re: How Safe is Your Hospital’s CT Scanner?

11/13/2010 9:23 AM

This problem is very universal.

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#6
In reply to #4

Re: How Safe is Your Hospital’s CT Scanner?

11/13/2010 12:01 PM

Sorry, but the statement "Typically you can't have a CT scan and go back to work at a nuclear plant" is completely untrue, as anyone with some knowledge of physics can verify. X-rays are absorbed by the body to various extents but never cause secondary radiation. Even in normal use CT scans require a higher radiation dose than plain X-ray examinations, but the danger of inadvertently giving too high a dose is present whether it is a plain chest X-ray or a CT scan. It is all a matter of operator training. Any facility which has a CT scanner should also have medical engineers who can check the machine, but stray radiation from a CT scanner is not a common problem.

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#7
In reply to #6

Re: How Safe is Your Hospital’s CT Scanner?

11/13/2010 1:56 PM

About the worker setting off alarms upon returning to work at a nuclear plant - it has happened. What is your expertise - being green?

They are not talking about a single x-ray. They are not talking about stray radiation - they are talking about excessive exposure from multiple x-rays over time.

Nothing to do with operator training - if excessive x-rays are ordered it is not an operator problem.

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Guru

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#8
In reply to #7

Re: How Safe is Your Hospital’s CT Scanner?

11/14/2010 12:45 AM

Sorry, but in repeating "the worker setting off alarms upon returning to work at a nuclear plant - it has happened." you are repeating an urban myth. It has not happened because it cannot happen. Subjecting a human to X-rays does not make him radioactive, however often you do it. Period.

As for expertise, I practised medicine for over 35 years in big hospitals. I tell you that if excessive X-rays are ordered it is an operator error because the doctor is as much a user of the machine as the technician. That is in any case irrelevant to the discussion of whether the patient becomes radioactive or not.

What is your expertise?

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#9
In reply to #8

Re: How Safe is Your Hospital’s CT Scanner?

11/14/2010 1:45 AM

I won't argue about the 'urban myth' thing now - I have to go back to people I know in the business for reference - however.

Practised medicine for 35 years? You are a doctor? Myself - a mechanical engineer.

It is not the doctors/dentists protecting their backsides from lawsuits that often call for more x-rays than necessary?

It is not the doctor that orders an x-ray having no idea of the patients recent background? How many other x-rays they have had in the recent past?

All the reports/discussions I have read about (in the US) are not about operator error - they are about unneeded x-rays being ordered by the doctor.

In much the rest of the world, equipment malfunctions and operator error should be assumed - I agree there.

Congrats about your 35 years as a doctor but you don't seem to be able to understand to topic - or possibly are in denial as doctors always seem to be when it comes to their profession.

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#12
In reply to #9

Re: How Safe is Your Hospital’s CT Scanner?

11/14/2010 4:30 PM

"It is not the doctors/dentists protecting their backsides from lawsuits that often call for more x-rays than necessary?"

Thank you for the gratuitous insult to the medical profession. If you had made that comment about an individual doctor you could be sued for libel. The medical profession as a whole is concerned with its own good practice, and over the years I have participated in many attempts to reduce unnecessary investigations of all kinds, not just X-rays.

"It is not the doctor that orders an x-ray having no idea of the patients recent background? How many other x-rays they have had in the recent past?"

Another gratuitous insult to the medical profession. I, like other doctors, take a history from a patient before I order investigations and make a diagnosis. Unfortunately, I encounter numerous patients who, for reasons of their own, choose not to make a full disclosure of their history. Indeed, some of them tell deliberate lies. Is it then the fault of the doctor to order the unnecessary investigation or is it the fault of the patient?

Now for your status as a mechanical engineer. You yourself obviously have not read the original reference given by the poser of the question. It is quite clearly stated there that the FDA investigated reports of radiation overdoses following a specialised CT scan procedure. Its recommendations were addressed not to the users of the machines but to the manufacturers of the machines. In other words, the machine was badly designed, to the extent that user errors were more likely. Is that the fault of the user?

Furthermore, do I conclude from the fact that you, as a mechanical engineer, have not bothered to read the evidence put in front of you, that all mechanical engineers are too lazy to read the evidence put in front of them? Or do I conclude that just some of them are too lazy?

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#15
In reply to #12

Re: How Safe is Your Hospital’s CT Scanner?

11/18/2010 10:09 AM

When I had kidney stones, the doctor had me in once a week for about 6 weeks to take x-rays to show how the stones (one in each tube between the kidney and bladder) were moving. I moved to Florida and went to the doctor there about the stones. He said I should not have any x-rays done for a long time (it was a long time ago and I don't remember exactly how long he said to wait) because of my "overexposure". He said the other doctor went overboard on the number of x-rays. It was not the technician's fault, it was the doctor. The Florida doctor said the other doctor should have known better. I'm sure CAT scan scheduling is the same. Doctors should know how much exposure the patients are going to have. The scans are recorded so the doctors should know how much exposure patients have had.

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#16
In reply to #15

Re: How Safe is Your Hospital’s CT Scanner?

11/18/2010 2:10 PM

You were unnecessarily exposed, but not dangerously overexposed. There was certainly no point in taking repeated X-rays of the stones, but the cumulative exposure you received as a result would not have stopped me ordering a chest X-ray the next day (had it been necessary for another reason). The cumulative dose of radiation you received would have been far less than some of the early angiography X-rays we used to undertake. So your first doctor was wrong to order too many X-rays, but the second doctor was wrong to worry so much about it. Have a look at this for dosages
http://www.radiologyinfo.org/en/safety/index.cfm?pg=sfty_xray

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Guru
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#17
In reply to #16

Re: How Safe is Your Hospital’s CT Scanner?

11/18/2010 9:36 PM

Exposure to organs having high blood contents causes more serious problems as each exposure reduces the contents of WBC in the blood and recovery time may be 30-days. Greater metabolism also has greater radiation impact.

If person exposed is already at typically low WBC contents then it may become a serious matter as one becomes susceptible to infection with less chances of fighting it back. Body immunity becomes very low with large number of x-rays to high blood content Organs or exposure to larger areas. Small area x-ray imaging is rather safer.

Then there is damage to the local Organ itself.

Some Organs are referred as critical organs with high sensitivity to Ionizing Radiation. Exposure to these to be minimized. One can take more hand and lag x-rays but not the same numbers to critical organs.

I think for stones Sonography should have been preferred as good alternative to see if body stones still existing.

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#18
In reply to #17

Re: How Safe is Your Hospital’s CT Scanner?

11/19/2010 1:32 AM

Specially Productive Organs

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#19
In reply to #18

Re: How Safe is Your Hospital’s CT Scanner?

11/19/2010 1:47 AM

Did you mean reproductive Organs? Yes, they are in the list of critical organs.

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#11
In reply to #8

Re: How Safe is Your Hospital’s CT Scanner?

11/14/2010 1:51 PM

Mr. Doctor,

X-rays can not make a person Radioactive. Neutron radiation can do that but you do not take human radio graphs with Neutrons.

X-rays can cause Somatic or Genetic damage to the body tissue and generic molecular structure. Process is statistical but has greater probability of damage with increasing radiation dose.

Each X-ray radiographic image may have local 100mR to 300mR exposure. Compare it with 2500mR maximum allowed Radiation dose for the radiation worker over a period.

CT- Scan takes multiple images and requires much larger exposure time so x-rays are not one shot but are either continuous or multiple shots to create many images.

It is wise to keep a record of how much radiation one has already received and if already acquired information is useful. In utter necessity Doctor have little choice between saving one life and increasing risk of x-ray induced radiation damage which may be temporary or permanent or there may be no damage worth counting. It is the risk factor that increases for sure but one has a choice of having proper some treatment.

Unless essential x-ray exposure to be avoided for sure.

Sometime it is so essential that it is worth going for it.

Technology now is capable to reduce the x-ray exposure by a factor of 10000 easily using ultra sensitive detectors that have very high gain and low noise and can pick image in much shorter time. However these are expensive research tools in hands of only few and are not produced like simple x-ray machine and x-ray film.

It is like night vision that enhances your capability to see in low light. Detectors with high gain and low noise just do that for creating image from very little x-rays exposure.

That is one reason that people question more about the high x-ray exposure because, having this better technology in hand, people are made to suffer with old technique still in use.

If you are keen to know about how much x-rays are really to be permitted then see ASRP reports, through some questions on Health Physics web site or write to INS, IAEA, WHO, NIH, DOE people working in these areas. In India AERB takes care of these matters.

Radiation damage by negligence is a very serious matter as ionizing radiation are invisible and effects does not show up immediately. It is not like a fire that burns, but may come in full horror after few days or several days or in next generation or next to next generation. It remains with the person like a hidden Ghost. Most of the time you can think that your Ghost is sleeping so nothing to worry about. What if it wakes up?

One reason for genetic mutation is exposure to ionizing radiation.

Just because one has undergone a CT scan, one need not worry about it too much. However, never make it a regular photo session to see inside word of one's own very often. I prefer to see it of many people who come under emergency for scanning help. It is something that you can't see otherwise.

Radiation exposure to the technicians, doctors and hospital visitors is also of concern. While professionals have to take risk hazard due to their job, others specially children and women must avoid it.

I am a WHO and IAEA trained Radiological Physicist. This knowledge is from part of our training and practice. However it is very little info as interaction of radiation with bio matter is a very big field. Sometime fear of cancer can cause more psychological damage than any real effect so please watch out.

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#13
In reply to #8

Re: How Safe is Your Hospital’s CT Scanner?

11/14/2010 10:58 PM

Regards.

I think it is more on part of a doctor as he is Human who decides tests by his experience; having no data of dose the patient had already got in a particular time-period.

while the Radiographer is using a computer aided machine which has all the data to compile for the test's requirements and set the machine ready to work on that data.

Auto-collimation to minimise exposed area, fastest setting on minimum exposure time and much more to ensure minimum dosage to the patient.

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Guru

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#10
In reply to #7

Re: How Safe is Your Hospital’s CT Scanner?

11/14/2010 11:47 AM

Regards.

I agree with you on the topic.

It is correct that it is the overdose of Radiations which is of concern; not only in CT scans but also where Radiations of any kind a re used as a Diagonostic Tool like of Patients [Including Mules and animals]; defects in Material or welds; treatment in cacer or else.

The requirement is of recording the dose given not only to Techs working but also of patients getting radiation dose during their treatment.

I had been working on X-Rays when 30/35 KV, 10/30 ma machines were used, very slow films and lack of knowledge on this subject. Several Techs & patients died of Leukemia.

Now it is of utmost requirement to ensure the minimum possible use of Radiations for the purposes.

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#14
In reply to #7

Re: How Safe is Your Hospital’s CT Scanner?

11/15/2010 4:34 AM

Getting 2 OT votes for that was unfair - I've just tried to counter it as I read this discussion.

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