Your doctor just ordered a CAT scan exam (also known as a CT scan). You may have read that CT’s emit a lot of radiation and are essentially bad for you.

But there is more information you should know to make an informed decision regarding your health. The CT is an amazing tool that doctors use to diagnose and monitor health problems; many lives have been saved over the years as a result.

CT had its emergence in the 1970s and has evolved into a tool of tremendous value. Its inventors never envisioned it reaching the current measure. Initial scanners only had a single detector which took 45 minutes to complete an exam of the head, and gave a very granular image which was challenging to interpret. Current machines can have up to 320 detectors, though most machines in use more commonly have from 16 to 64 detectors, with images that are astoundingly detailed, and require less than five minutes to acquire images. These are the workhorse machines that you will find in your local health care facilities. Today’s machines are very fast and give the high quality images that modern medicine requires.

It is true that the amount of radiation that is emitted from these machines has grown, as the machines have become larger and faster. In recent years, in response to this increasing radiation exposure, there has been a movement to reduce the amount of radiation emitted through a combination of manufacturing advancements and adjusting our standards for image perfection.

CT manufacturers have developed dose-reducing software that allows for the same quality of exams and can be applied to machines already in use. Now even hospitals with established equipment are able to reduce the amount of radiation exposure to patients. Radiologists, too, are involved in helping lead these changes by adjusting their standard to accept images with slightly more granularity in exchange for the lower dose. This is similar to the difference in your home between an HD television and the prior generation; clearly different, but you are still able to see all the necessary elements of the presentation. In the process of these changes, patient care has not been found to suffer in any way.

My hope is for patients to make good health care choices for themselves with the guidance of their physician. Ask questions, not only of the doctor but also of the technologist that is preparing to perform your exam. They are full of information; information which is correct and current.

• Gregory Merrill is Director of Medical Imaging at Snoqualmie Valley Hospital.