How to Choose the Best Medical Imaging Scan

Today we take it for granted, but internal medical imaging is little more than a hundred years old. X-rays were discovered in Bavaria by Professor Wilhelm Roentgen in 1895. He was looking at the path of electrical rays created by an induction coil passing through a glass tube holding a partial vacuum. Even though the room was black and the tube was covered, Roentgen noticed that a fluorescent screen was lit up by the radiation. When he passed his hand between the screen and tube, he could see his own bones. Presented here is the first X ray put on film. It belongs to the hand of the professor's wife. Note the wedding ring. For the first time a doctor could see the inner structure of a body without cutting it open. Medical imaging spread rapidly as a specialty. Today we have several options. Let's look at their advantages and disadvantages.

Instructions

• 1

  Today simple X-rays are fast and cheap producing a low dose of radiation. They are used routinely in dental offices, and for diagnosing broken bones, lung cancer, pneumonia and intestinal blockages. They only provide two dimensional images. In the 1930's X-rays were often used to treat chronic acne, a remedy that has fallen out of favor because of increased appreciation of the hazards of the radiation involved. X rays work best with bones, but not with soft tissue.

• 2

  Computerized Axial Tomography, CAT or CT Scans, produce three dimensional images of a body by combining a series of razor thin X-ray slices through sophisticated computer software. Introduced in the 1970s, CT Scans have grown so popular that U.S. doctors ordered 68.7 million of them last year. The process can produce detailed images of kidney stones, and coronary artery blockages. According to Dr. Michael Brant Zawadski, Clinical Professor of Radiology at Stanford University, CT Scans have the potential at detecting lung cancer early enough to substantially alter the disease's prognosis, which now has a survival rate of only 15% for the five years after detection. CT Scans are controversial. They are huge money makers for medical facilities. Some doctors are accused of over prescribing them even though the radiation involved is about the equivalent of 100 chest X rays. A recent study in the New England Journal of Medicine suggests that repeated CT-Scanning can increase a patient's cancer risk by 2%. At Cedars Sinai Medical Center in Los Angeles more than 200 patients got massive radiation overdoses from miscalibrated machines, prompting an FDA warning. For a video that looks in detail at the pros and cons of the process, go to my You Tube Video "CT Scan." The hot link is below.

• 3

  Magnetic Resonance Imaging, MRIs can be more detailed that CT scans providing better soft tissue contrast. MRIs put people at less risk, because they use no radiation. Instead they employ a powerful magnetic field to magnetize the hydrogen atoms in the body to produce an image detectable by the scanner. The process dates to the late seventies. MRIs are more expensive than CT Scans and require a patient to remain still in a noisy, claustrophobia inducing tube for a half hour or more.

• 4

  Ultrasound is inexpensive and also uses no radiation. It sends a pattern of sound waves with a higher frequency than the upper limit of human hearing into a body to produce an image. Unfortunately it can heat soft tissue and produce an inflammatory response so it is best used in scans of short durations. It's often employed to look at fetuses and to detect appendicitis in children.