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12/18/2009 - News

More News About CT Scans and Radiation

By: June Chen, MD

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The use of CT scans for medical evaluation and diagnosis has dramatically increased over the past 20 years. Even though CT scans are associated with a higher dose of radiation than conventional x-rays, the doses of radiation are not well-known. In the December 14/28, 2009 issue of Archives of Internal Medicine, researchers report that radiation doses from some common CT scans may vary, depending on where the CT scans are performed.

Investigators from the University of California, San Francisco and their colleagues conducted a study to estimate the radiation dose associated with the 11 most common types of CT scans performed on 1119 consecutive adult patients at 4 San Francisco Bay Area institutions between January 1 and May 30, 2008. They also sought to estimate the lifetime cancer risk attributable to the different types of CT scans based on these measured doses of radiation. The investigators found that radiation doses varied significantly between the different types of CT scans. They also found that, within each type of CT scan, the effective radiation dose varied by quite a bit both within and across institutions.

Due to this variation in radiation, the estimated number of CT scans that would lead to the development of a cancer varied widely as well. The researchers estimated that 1 in every 270 women who undergo CT coronary angiography at age 40 will development cancer from that CT scan, as compared to 1 in 8100 women who had routine head CT scans.

Although this study was limited to just four institutions in a single geographic, the findings of the study do suggest that the radiation doses from common-performed CT scans may be higher and more variable than expected. The researchers conclude that this variability highlights the need for greater standardization of the protocols for CT scans.

 

Source:

Arch Intern Med 2009;169(22):2078-2086.

 

Created on: 12/18/2009
Reviewed on: 12/18/2009

Your rating: None Average: 4 (3 votes)
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Anonymous wrote 5 weeks 12 hours ago

I'm going on 18 years of performing CT's and MRI's on patients. These test should be done in moderation. Hospitals and out patient centers should have their administrators educated on radiation risks vs $$$$$.

Anonymous wrote 5 weeks 14 hours ago

I am a CT tech. I have been for about 17yrs.. When I first started a routine abdomen/pelvis scan would take 45min to and hour. Since the newer scanners started more and more scans get ordered. It has made it to easy to get a diagnoses for bonehead ER docs.. They don't doctor anymore. There are plenty of times people come in with a migraine and get CT heads. It is ridiculous. If a patient comes in with right lower quadrant pain ,and has a high white blood cell count ,and still has their appendix we still do the CT. Back 15 years ago they would just take that patient to surgery. Doctors do more CYA (cover your ass) than anything else.....There are times that triage nurses are given the power to order CT scans also. Patient never sees a doctor and a triage nurse orders a $1500.00 procedure that is not needed

RT,CT

Anonymous wrote 5 weeks 14 hours ago

Don't worry if oama and his stooges get thier way nobod will be getting a CAT scan even if thier lives depend on it.
RT.CT.MR

Anonymous wrote 5 weeks 15 hours ago

I to am a Rad/CT tech, did anyone stop and look at the fact that out of 270 heart scans or 8100 head scans how many of these peoples lives were saved because of some undelying health issue that a CT scan found, there is a reason why your doctor ordered this study if you have questions ask.

Anonymous wrote 5 weeks 13 hours ago

Thank god the ER did my head CT scan after complaining about uneven balance, massive headaches, and dizzy spells just 3 months after my son was born. What was found was a "mass" that turned out to be a low grade glioma, located in the pituitary gland, pressing on my optic nerves and almost causing blindness! Surgery done a few weeks later. One year later I am 100% better.

Anonymous wrote 5 weeks 15 hours ago

I had a CT Scan sheduled for tomorrow morning, I think I may cancel it. It was ordered only because I told the doctor I have been having dizzy spells every now and then. All my blood work came back normal. Not sure if I should even have a CT Scan at this point.

Anonymous wrote 5 weeks 14 hours ago

My friends mom had dizzy spells and the doctors kept telling her it was menopause - 4 months later she collapsed and was rushed to the hospital - it was a brain tumor and by the time they discovered it, it was too large to remove. It's better to be safe then wait too long.......

Anonymous wrote 5 weeks 17 hours ago

I work in the commericial nuclear power industry and I have been wondering when the medical field would finally come under some scrutiny with respect to control of radiation dosage. For example, the average worker at a nuclear plant picks up around 1000 millirem (or 1 rem) of dose per year. Background radiation from the sun and other natural sources results in the average citizen picking up around 300 millirem per year. One heart stress test using nuclear medicine equates to about 9 rem!!!! This is more ionizing radiation than a nuclear plan worker would pick up in a career and the fact that the patient receives this dose in a short time is of even more concern. So, beware of your health, you have to weigh the positives and negatives but I know some tests are ordered without regard to cost (your wallet) and your health. If you ask the average doctor, they have no idea how much dose you are getting. The technicians may know, but they don't understand the health risk.

Anonymous wrote 5 weeks 13 hours ago

You need to check your facts before you speak. As a Registered CT tech, I HAVE to know the risks of radiation to my patients. We are very well trained in the doses received and the Health Risks of having any type of Radioliogic procedure. A skilled technologist knows how to explain the facts, and the risk factors to their patients, and we DO care.

Anonymous wrote 5 weeks 15 hours ago

Where are you getting your information? Being a nuclear medicine technologist I know what the risks are, and I know what the radiation absorbed dose is for the patient. You claim that a stress test is 30 times greater than a yearly background radiation dose. This is not the case it is only 4 times more than the amount of the yearly background radiation dose. Only about 1 rem or 1,000 mrem for a nuclear stress test. You have to decide for yourself if it is worth the risk or not for yourself. If my health was in question I would want the test. You have to think of the people (like me) who are exposed to radiation everyday. We are monitored just like you are. We went to school to learn about radiation safety much like I am sure you did.

Anonymous wrote 5 weeks 13 hours ago

Well, I'm a PhD in nuclear engineering and know that research is currently underway to make better detectors to shorten the time the patient is on the table, which would result in a lower dose to the patient. If it is true the amount of dose is only 4 times more than background, then I believe the study they did is completely wrong. The test has several loop hole in the fact they don't say what type of detectors they used to calculate the dose, don't include a standard deviation, and the list goes on. Some detectors can have pages of calculations associated with them. The most interesting part would be the type of detector used. Lets say a NaI scintillator was used, well sodium and iodide (high Z materials) do not match the materials in our own bodies, which is mostly hydrocarbons (low Z materials). The probability of radiation interacting with a material is definitely depended on the type of material being used as an absorber (i.e. Z-number). I personally do not believe the study they performed, but am curious what the correct amount of dose from the CT scan is compared to background.

Anonymous wrote 3 weeks 6 days ago

Sorry, but you're wrong about the pt scan time and dose. Faster scans = higher levels of radiation. You get a C on that test.

Anonymous wrote 5 weeks 16 hours ago

You need to give the Technologists a little more credit than that, we do go through extensive radiation protection in RT school. We do know the risks, however, this is our profession and part of that is to question orders that appear to be excessive on the patients behalf to the Radiologist . He/She is the one to make the final determination if the scan is necessary or can the same result be achieved by some other diagnostic modality.

Anonymous wrote 5 weeks 18 hours ago

I am a CT Tech, and I can tell you one of the best ways to reduce the amount of radiation to patients is to reduce the # of scans that you do with and without contrast. Many pt's come in for scans that their doctors have ordered with and without contrast for no particular reason. I will scan them only with contrast UNLESS this is a follow-up exam to another one that has already been performed and there is a known mass/lesion that they want to see how it enhances. Then, and only then, will I scan with and without contrast! It cuts that pt's dose in half just by doing that. The type of scanner and good competent field engineers, physicists and techs play a huge role in the dosing also.

Anonymous wrote 5 weeks 16 hours ago

I have been a CT technologist since the late eighties, and I have often questioned the necessity of "routine scans" comming from the ER or outpatient facilities for anything from rule out cranial hemmorage to aneurysm and we have to ask ourselfs how many peoples lifes have we saved vs. Doctors covering their sixes. Risk vs Benefit.

Anonymous wrote 5 weeks 14 hours ago

LAWSUITS --that is the healthcare reform we need
RT.R.CT.MR

Anonymous wrote 5 weeks 16 hours ago

What about the high levels of radiation given for cancer treatment? I had 35 days in a row with weekends off with my breast cancer and I have trouble breathing now and it has been 5 years ago, I have been trying to get answers. Thanks

Anonymous wrote 5 weeks 18 hours ago

I am also a CT tech and can say that I have never held a patient while the scan is taking place. There are velcro straps we can use if the patient is unable to hold still for the exam.

Anonymous wrote 5 weeks 21 hours ago

I'm a CT Tech and no techs ever hold for a Scan. We do hold sometimes for regular x-rays!

Anonymous wrote 5 weeks 21 hours ago

They should do a study on the Techs who are around it every single day, and see how many of them have cancer from the radiation. (I would think the techs would receive more radiation than any 1 scan, because they cant always stand behind the lead, they have to hold some people i am sure)

Anonymous wrote 5 weeks 15 hours ago

I am a young x-ray/CT tech at hospital. I never hold patients during studies, I hide behind the lead wall when doing the study, and if I have to do a portable x-ray, I wear a lead apron and back away from the radiation beam.

Yes, studies have been done and there ARE maximum dose limits that a technologist is allowed to recieve. We wear monitors that measure our radiation intake. If we are getting too high of doses, we have to reevalute our safety protection. With today's safety guidelines, it is very unlikely that a modern day CT/x-ray tech would get radiation induced cancer.

Anonymous wrote 5 weeks 16 hours ago

CT techs have rules and guidelines we use to keep ourself and our pts safe. We also never hold pts during scans

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