Controversies And Developments In Medical Imaging

Jason Guinn Articles From Our Physicians

By Dr. Ken Hager

Dramatic progress has occurred in the technical aspects of medical imaging, with unfortunately similar dramatic regression in some administrative components.

PACS, the cloud, pads and pods: The same technology that lets you text and check messages can be used to check for reports or even view images from medical exams. Advanced Imaging has been using this and one form or another since we opened; most hospitals are now doing something similar. Essentially, with a brief downloaded application to your computer or phone and a brief verification mandated by HIPAA, physicians can communicate directly to the server and pull down information on their patients from anywhere with internet access.

Radiation, CT, and patient exposure: Several years ago some characters in California took the highest dose CT machine on the market, modified it significantly and managed to expose patients to significant radiation doses. We have recently replaced our original 2004 CT with a machine which operates at half of the previous dose. The dose on our original 2004 machine was 1/30 the dose of the unmodified/original California machine, which is itself no longer manufactured. A factor which should be considered in comparing CT radiation doses versus x-ray is that the CT dose includes all slices; given an exam that has 100 slices, each portion of the body covered receives only 1% of the total exam dose; whereas, each portion of the body exposed to an x-ray received 100% of the exam dose.

A frequently quoted study indicates that infants that received numerous CTS in infancy had various problems later in life. Normal infants do not receive numerous CTS in infancy. Infants with this level of difficulty would have numerous problems later in life if they did not receive CTS, assuming they survived without the CT information they were denied.

Radiation dose is cumulative: Unless you still have the first sunburn you ever received, you know this is simply not true. Many years of chronic over exposure to the sun does have some chronic effects.

3D Mammography: This process acquires a 2D digital exam, then acquires data to synthesize multiple slice images through the region. Total x-ray dose is only slightly greater than a 2D exam; Several studies have confirmed a 30-50% increase in sensitivity for finding breast cancers. The calculated risk from the radiation dose for mammography is equivalent to smoking 3/5 of one cigarette once in your lifetime, driving 5 miles, breathing the air in New York City for 2 days, or spending 8 minutes in a canoe. The risk of a woman developing breast cancer in the United States is one in 8, over approximately a 40 year span, or approximately I in 320 per year. The increased morbidity and mortality from the delay and diagnosis of a breast cancer for one year is considerable. In short, the radiation risk from having a mammogram is between 300,000 to I million times less than the risk of not having a mammogram.

The mammography controversy: Another study that is being increasingly frequently quoted is a Canadian study comparing mammograms versus physical exams on patients 25 years ago and claiming no statistical difference in subsequent patient survival. This study has received significant criticisms; physical exam was performed on patients at the origin and all patients with palpable masses were put in the mammography arm of the study. Mammography interpretation was performed by physicians with 4 weeks of training. The average size of a mass found at mammography was 2 CM. A more appropriate conclusion from this study is that it is a good thing that mammography is not currently done he way Canadians did it 25 years ago. Dramatic technical improvements in mammography such as digital and 3D imaging have changed this field in the same way that cameras, computers, and telephones have changed “slightly” in the last 25 years as well. Finally, Stevie Wonder does not read our mammograms in the US.