Lower Dose CT Scan

While CT is a very good and rapid diagnostic tool, it exposes the patient to radiation during acquisition of the images. Cardiologist Dr. Michael Poon says the typical cardiac CT scan provides a radiation dose on the equivalent of 100 or more chest X-rays. Over time, some health experts worry that accumulated exposure to radiation (through other medical scans) could potentially increase a person’s risk for cancer. The risk is especially a concern for children and young adults, who have many more years of life to be exposed to medical sources of radiation.

Poon says that, generally, the larger the person, the higher the dose of radiation needed to obtain clear images from the CT scan. In the past, most CT scans were set to a higher radiation dose so the machines could accommodate larger size bodies. But that means that smaller adults are unnecessarily exposed to high doses of radiation.

Over the past few years, experts have called for a lowering of radiation doses for CT scanners. Researchers are finding ways to accomplish those goals. Poon says lowering the voltage of the machine by 20 volts can reduce radiation exposure by as much as 50 percent, without sacrificing the quality of the image or the diagnostic accuracy of the scan. Poon is now teaching doctors around the world how they can adjust the dosage of radiation of CT scanners. Technological advances are also helping. Some of the newer CT machines require less radiation for a scan.