Why doesn't my doctor always choose a test without harmful radiation?
There are many possible reasons. Most importantly, we would not offer a test we felt was dangerous. The risks of a diagnostic test like CT or x-ray are extremely low and, at this point, theoretical. There has as yet not been any evidence that the low doses from diagnostic testing are linked to the development of cancer. Another reason is that for certain conditions and diagnoses, x-rays, CT scans, and nuclear medicine are indispensable. Further, not all scans or people are the same--the adult brain is relatively insensitive to radiation, but the breasts aren't, so your doctor will consider what area of the body is being exposed. Also, most of the growth of the body and turnover of important cells happens early in life. Once we reach adulthood, the risks of radiation decrease dramatically. Finally, your doctor, in consultation with your radiologist, has considered the risks for your particular condition. If you have a life-threatening problem or a serious disease, the near-trivial risks of radiation are just not as important as your pressing condition.
What is the risk of the radiation I will receive?
Incredibly low. We don't know exactly how low, and that is the only fair answer. Most of the data on cancers induced from radiation is from incidents with incredibly high radiation exposures, like high-dose radiation therapy for cancer or from atomic bomb blasts. These doses are literally tens-of-thousands times the magnitude of radiation used in diagnostic testing, and so the comparison is not accurate. For example, water at 200 degrees Fahrenheit will burn your skin, but water at 100 degrees never will (remember, our bodies are normally 99 degrees to begin with!). It is simply not accurate to say half the heat will lead to half a burn. So at one ten-thousandth of a dangerous dose, we do not want to raise undue alarm. Nonetheless, since the risks, however low they are, are not precisely known, we are cautious with radiation and minimize or optimize its use when possible.
What if I am completely unwilling to undergo radiation?
That is every patient's choice and right. We support the patient's informed decision on whether or not to undergo a test. One thing to keep in mind, however, is that we are all exposed to radiation every day, just by living on earth. There is background radiation from natural sources, from the ground and even from the things that we eat. There is also radiation coming from cosmic rays; this radiation is magnified at altitude, so residents of high-altitude cities like Denver and frequent fliers in jets at 30,000 feet experience more radiation than those of us at sea level. In fact, the cosmic radiation at Denver is approximately twice the level at sea-level, yielding the radiation equivalent of an extra 3-4 chest x-rays per year. Just by choosing where to live you might unknowingly (and trivially) increase your daily radiation exposure; certainly for a medical problem it is worth considering radiation to get to the root of it.
What does RASF do to limit radiation exposure?
RASF follows the principle of ALARA - as low as reasonably achievable. We use a medical physicist to fine-tune our machines and make sure that they are not emitting high levels of radiation due to malfunction or leakage. Many other radiological providers may choose not to have a physicist frequently check their equipment, but we feel it is important to make sure doses are as low as possible. We use shielding when practical to help protect areas of the body that do not need to be exposed. We collimate the x-ray beam to its smallest possible geometry.
In fluoroscopy, we limit the amount of time you are under the x-ray beam, whether for a barium swallow or an interventional procedure. Having subspecialists is key to this; the better your physician is at fluoroscopy, the less time he or she needs to make a diagnosis or perform an intervention. In CT, we use body mass index (BMI) protocols to tailor radiation dose to the size of patient. We use special low-dose examinations for pediatric cases and for screening exams. We also limit coverage of what is scanned to the areas that are requested. RASF is proud to be one of the first large radiology groups in the country to incorporate system-wide iterative reconstruction to our CT scanners. ASIR (Adaptive Statistical Iterative Reconstruction) is a software algorithm that can be applied to certain CT scanners in order to significantly reduce radiation dose while maintaining a high level of image quality. All of our CT patients now benefit from ASIR, which is not available at most other imaging centers.
Overall, we are relentless in trying to limit radiation dose to patients. We speak to your physicians, attempting to substitute examinations without harmful radiation when possible, or trying to get old comparison studies to help avoid a new study. Two of our RASF radiologists, Juan Batlle, MD, and Kenneth Mendelson, MD, were recently invited to speak at South Miami Hospital at a symposium on reducing radiation dose, "CT Dose Reduction; A Comprehensive Approach" (November 5, 2011). Our president and CEO, Ricardo Cury, MD, led the effort for introducing ASIR to Baptist Health South Florida facilities system-wide. You can rest assured we take the topic seriously and are doing all we can to address it so you can have peace of mind in your time of health care need. Dr. Warren Janowitz is currently the chairman of the radiation safety advisory committee for the Department of Health of Florida. This position is a critical one in safeguarding the safety of patients.
