The Changing Laws
Editor's note: Because of a number of inquiries, we are reprinting this May, 20, 1994 article.
When the Radiation Safety/Quality Assurance Program was adopted in 1991 by the New York State Department of Health (NYSDOH), many medical and chiropractic practitioners expressed surprise at the stringent guidelines. The program stressed that immediate compliance with these new state guidelines was mandatory, and that "facilities may not wait until their next inspection to begin a program."1
This adopted program had one purpose: to reduce radiation exposure by optimizing diagnostic x-ray image quality.2 In part, this program requires that film processing conditions be assessed daily by means of sensitometer strips. These strips are "read" by a densitometer. The values for film speed, film contrast, and the base + fog must then be plotted. If any of these parameters fall outside of the accepted upper or lower limits, an immediate remedy must be undertaken. A precursor to the federal regulation of the health care industry, the New York program became a model for several similarly proposed programs throughout the nation. Similar administrative rules or laws requiring processor monitoring were implemented in Minnesota in September 1991, Maine in 1992, and in Texas in January 1992.
Mammography Leads the Way
On the federal level, the Mammography Quality Standards Act (MQSA) was adopted in 1992 "to establish authority for the regulation of mammography and radiological equipment, and for other purposes."3 According to the act, all facilities, personnel, and equipment must be certified by an independent accreditation board established by federal authorities. Among other provisions, MQSA mandates for the first time ever, the use of high-frequency radiographic systems for every mammogram performed in this country. Strict enforcement of of the MQSA began October 1, 1994.While MQSA is directed at the mammographic industry and breast health care delivery, the chiropractic and medical professions should also expect to experience new federal and state legislative changes regarding the delivery of radiography and radiologic services. In the future, practitioners will no longer be able to operate their x-ray and processing equipment without regular state inspections. Also, entrance skin exposure limits will become more common in states that currently have no such limits and the existing maximum allowable limits will probably be reduced over time. The sweeping changes that will be imposed during this period of managed health care will also affect the radiation regulatory agencies.
What the Future Holds
The New York, Maine, Minnesota, and Texas programs and MQSA are signs of what is to come for the rest of the radiographic community in this country. We can expect stringent federal regulations governing the operation and performance of our radiographic equipment. It is my opinion that three phase and high frequency equipment will become the only acceptable means of obtaining a radiograph in this country, as has already occurred in several other countries such as Germany, the Netherlands, and the United Kingdom. At this time, over 95 percent of the new x-ray equipment purchased by the medical profession is high frequency equipment.4 In addition, a large contingent of states throughout the United States already monitor and enforce maximum dose levels for specified anatomical views. According to a 1992 survey by the Conference of Radiation Control Program Directors, 12 states had legislated maximum entrance skin exposure limits (Delaware, Florida, Georgia, Illinois, Maryland, Michigan, Minnesota, New York, Rhode Island, Texas, Vermont, and Virginia).
Many office-based practices currently utilize single phase equipment. This technology dates back to the discovery of x-rays in 1895 and is far less efficient, yields a lesser quality image, and results in a higher patient dose than today's high frequency systems. Although single phase is traditionally less expensive and easier to operate than other equipment, it is outdated and professionals may find that new federal regulations will prohibit its use on humans.
Single Phase, Three Phase, and High Frequency Generators
Since single phase x-ray equipment only emits usable, penetrating x-ray waves at the peak of the kV wave, patients are subjected to longer exposure times and also absorb more soft, inefficient radiation (bremsstrahlung radiation). While three phase equipment is a substantial improvement over single phase generated x-rays, inefficiency in the kV waveform still occurs, with as much as 18 percent kVp and 50 percent mR ripple effect. Three phase is also considerably more expensive in regard to installation and operation, since three phase power lines must be installed to accommodate the equipment. A true high frequency generator produces a kV waveform with a ripple effect less than five percent.
Mid Frequency vs. High Frequency Generators: The True Story
Some so-called high frequency equipment is actually only mid frequency, operating at between 6 and 38 kHz.5 These generators produce an irregular ripple and have a slower rise and fall time in the kV wave. True high frequency actually begins at 40 kHz and has substantially less ripple, provides greater technique accuracy and film contrast, shorter exposure times, and lower patient dose.
A Message to the Chiropractic Profession
By our very nature as chiropractors, we must strive to institute the safest, most effective, and least intrusive means of wellness. This includes the use of radiology as a diagnostic tool. When safer, more efficient radiographic systems are available, we should attempt to eliminate our use of inefficient, higher dose radiographic systems. And we should do it before our government imposes this upon us.
References
- New York State Department of Health letter, dated March 15, 1992.
- Guide for Radiation Safety/Quality Assurance Program. New York State Department of Health, p. 1.
- "Mammography Quality Standard Act," HR 6182, page 1.
- Medical Imaging, April 1994, p. 57.
- Curry TS, Dowdey JE, Murray RC: Christensen's Introduction to the Physics of Diagnostic Radiology. Third ed., Lea & Febiger, Philadelphia, 1984.
Terry R. Yochum, DC, DACBR
Federal Heights, Colorado
Dr. Terry R. Yochum is a second-generation chiropractor and a cum laude graduate of the National College of Chiropractic, where he subsequently completed his radiology residency. He is a diplomate of the American Chiropractic Board of Radiology and served as its vice president and president for seven years (1983-1990). An adjunct Professor of Radiology at the Southern California University of Health Sciences and member of the Department of Radiology at the University of Colorado School of Medicine, Dr. Yochum is the co-author of Essentials of Skeletal Radiology – the required textbook in radiology at all 50 chiropractic colleges and used in more than 100 medical schools around the world.