Porter Hospital Blog

According to two reports published in the Archives of Internal Medicine this month,which we reviewed recently on The Denver Channel,  the number of CT scans performed in our country jumped from 3 million per year in 1970 to 70 million in 2007. While CT scans are an important tool providing great medical benefits, they also involve much higher doses of radiation than routine X-rays. In fact – the radiation from a chest CT scan can be more than the radiation dose from 100 regular chest X-rays. The study raised concerns about an increase in certain cancers from the amount of radiation that patients are being exposed to over their lifetime from CT scans.
Let’s discuss what this article means for each of us.

First of all, why do CT scans have so much more radiation than a regular X-ray?
A regular X-ray – or plain film as we call it – is a beam of radiation shot through the body from one side to the other, where a special film picks up the radiation and provides a view into the body – air appears to be dark and water-filled things appear more white, with various organs having shades in between. It allows physicians to “see” inside the body in a flat view. A CT scan is a series of regular X-rays mounted on a circle and connected to a computer. The computer takes the shadows from the series of images done and reconstructs a picture of a person that looks like a slice of the person and has much greater detail than a plain film. Since it takes multiple X-ray beams to construct the image, the radiation dose is higher.
So, CT scans are very useful in seeing the organs inside of the body and finding tumors, infections and other problems. In fact, we can now see the placques in coronary arteries that used to require a cardiac catheterization to see.

What was the article’s concern about cancer?
It is important to note that this was not a study that followed actual patients.
In one report, they looked at doses of radiation that 1,119 patients at a hospital had received from CT scans and then calculated the lifetime risk of developing cancer in those patients. In the other report they showed that up to 29,000 cancers could be caused by the current doses of radiation in CT scans

What is being done about this?
At Porter, for example, we are have been doing many things to address these concerns.
1) We are trying to reduce the dose of radiation for each CT scan without changing the quality of the picture. In fact, our lead heart CT radiologist, Dr. Simeon Abramson,  has done ground-breaking work with Siemens to  reduce the dose from a CT angiogram of the heart from the equivalent of 100-140 chest X-rays to the equivalent 0f 10-30 X-rays – making it less than the dose of radiation from the traditional cardiac catheterization.

2) The hospital radiology department is creating systems to track total radiation doses patients are receiving from tests done at our facility
3) We have systems in place that stop physicians from ordering radiology tests that will not give them the best information and are working with them to get a better test

What can patients do?
It is always appropriate to ask your physician why they are ordering a test, and what the risks and benefits are to you.
Also, it is a good idea to tell your physicians about any X-rays you had done elsewhere. They can get a copy of that test and you can avoid a second test.

For more information, you may want to look at the following sites:

Centers for Disease Control

American Nuclear Society – Calculate Your Radiation Exposurefrom all sources

Porter Hospital Health Library

Good Health!

Dr. Dianne