Part 1. Major Surgical Advances
Go Hand in Hand with Extensive Use of X-Rays
No one can deny the fantastic advances in cardiovascular and other major surgery in the 20th Century.
For example, the ability to correct some major congenital abnormalities in infants and children can convert a very limited and unhealthy life for a child into a life with essentially normal span and normal activity. And at various ages, head surgery, heart-valve replacement, arterial bypass, reduction of luminal obstruction, and peripheral vascular surgery are successfully accomplished, and the procedures are steadily improved.
Most of these surgical triumphs, and many others, have required information gleaned from the use of roentgenographs and roentgenoscopy. A wide variety of studies with catheterization are done under fluoroscopic observation, and observation can require extended periods of time.
It is simply inevitable that such procedures are characterized by much higher radiation doses, often to the breasts, than is the case for usual diagnostic roentgenology. Chapter 32, Part 3, lists average doses to patients as of the 1970s from various radiological investigations of the heart and great vessels. Occasionally, dose-levels in cardiovascular procedures are high enough today to cause "radiation burns," as reported in Chapter 32, Part 5.
Indeed, the currently high levels of dose delivered in some cardiovascular and other examinations are causing concern in the Food and Drug Administration's Center for Devices and Radiological Health (see Part 2).
The Same Benefits with Lower Risk
Surely, no one would consider inhibiting the correction of a major congenital heart lesion, or multiple lesions, which can change misery into happy life for a child. Nor would anyone consider inhibiting a quality-of-life improvement in an adult with a correctable vascular problem. These hardly require discussion. The issue worth attention is avoidance of radiation doses higher than necessary, and prevention of unnecessary injury not only to the patient but also (by scattered radiation) to the nurses, physicians, and technicians.
A child with a corrected heart defect who does not later develop an unnecessary breast-cancer is far preferable to one who does develop that cancer. A nurse, technician, or physician who develops an unnecessary radiation-induced cancer represents a serious failure in medicine.
When are unnecessarily high dose-levels of radiation most likely to occur in surgery? Whenever there is inadequate attention to the radiological part of the surgical advance and only a vague appreciation of radiation carcinogenesis.Part 2. Some Win-Win Advice for Patients and Medical Personnel
On September 30, 1994, Dr. D. Bruce Burlington, Director of the Center for Devices and Radiological Health (Food and Drug Administration), issued a 3-page FDA Public Health Advisory: "Avoidance of Serious X-Ray-Induced Skin Injuries to Patients During Fluoroscopically-Guided Procedures" (Burlington 1994). Under the same title, a 6-page version had been issued by the FDA on September 9, 1994 (FDA 1994).
Readers will soon see that the title of both versions is a bit understated. At issue is protection of numerous medical personnel as well as patients, and protection from far more than skin injury alone.
The Advisory went out to Healthcare Administrators, Risk Managers, Radiology Department Directors, Cardiology Department Directors, and to eleven medical specialty associations. All of us can feel proud of this manifestation of excellence and concern on the part of Dr. Burlington, his associate, Dr. Thomas B. Shope, and their staff at the Center for Devices and Radiological Health. Many lives will be bettered by this timely and valuable guidance to the medical profession, presented in a clear and effective manner.
We will quote from the beginning of the Advisory (Burlington 1994), which spells out the problem and the wide range of medical procedures at issue, involving not only the heart but also the gallbladder, pancreas, liver, kidneys, bladder, and major blood vessels:
"The Food and Drug Administration (FDA) Center for Devices and Radiological" Health (CDRH) has received reports of occasional, but at times severe, radiation-induced skin injuries to patients resulting from prolonged, fluoroscopically-guided, invasive procedures. Procedures typically involving extended fluoroscopic time are:
percutaneous transluminal angioplasty (coronary and other vessels),
radiofrequency cardiac catheter ablation,
stent and filter placement,
thrombolytic and fibrinolytic procedures,
percutaneous transhepatic cholangiography,
endoscopic retrograde cholangiopancreatography,
transjugular intrahepatic portosystemic shunt,
biliary drainage and
urinary/biliary stone removal." And:
"Physicians performing these procedures should be aware of the potential for serious, radiation-induced skin injury caused by long periods of fluoroscopy during these procedures. It is important to note that the onset of these injuries is usually delayed, so that the physician cannot discern the damage by observing the patient immediately after the treatment [emphasis in the original]."
And in FDA 1994, times between exposure and adverse skin reactions are indicated:
Hours for early transient erythema.
>10 weeks for dermal necrosis.
> 6 weeks to secondary ulceration.
The Cancer Hazard for Patients, Physicians, and Staff
It would be a mistake for anyone to assume that only the patient can receive radiation exposure from "prolonged, fluoroscopically-guided" procedures. Some parts of the original x-ray beam intercepted by the patient, or by any other person or object, become scattered and change direction (for example, see Chapter 31, Part 2). So even procedures which do not irradiate the breasts of a patient can, by scatter, cause some breast irradiation of female medical personnel.
The FDA is well aware of this, and of its implications for patients and medical personnel. We quote from FDA 1994 (p.3):
"Procedures of the type described here may also increase the risk for late effects such as radiation-induced cancers in other tissues and organs. The potential for such late effects should not be disregarded in risk/benefit considerations, especially for individuals with many decades of expected life remaining, such as pediatric and young adult patients, or for procedures involving absorbed dose to radiosensitive tissues such as the breast. These interventional procedures can also result in increased occupational exposure to physicians and staff, and efforts to reduce the exposure to patients will result in reductions in the exposure to those conducting the procedures."
The statement could hardly be more clear and to the point.Part 3. How Much Radiation Are Patients Receiving in Such Procedures?
The doses received by patients during fluoroscopically-guided procedures are determined by the dose-rate per minute and the total number of minutes the beam is on. We quote FDA 1994 (pp.2-3):
"The absorbed dose rate in the skin from the direct beam of a fluoroscopic x-ray system is typically between 0.02 and 0.05 Gy/min (2 and 5 rad/min), but may range from 0.01 to more than 0.5 Gy/min [1 rad per minute to more than 50 rads per minute] ..." Referring to the rates of 2 rads / minute and 20 rads / minute, FDA 1994 continues: "These dose rates are, respectively, the usual or typical dose rate for normal fluoroscopy for an average-size patient and a dose rate near the maximum which will be permitted for high-level control mode of operation under a recently established Federal limit [cites Federal Register of May 19, 1994, pp.26402-26405]. Thus, even typical dose rates can result in skin injury after less than one hour of fluoroscopy [emphasis in original]."
Table 2 of FDA 1994 lists twelve levels of skin injury, the absorbed dose from which they can result, and the time to onset of effect:Effects Early transient erythema 200 rads Within hours. Temporary epilation 300 rads 3 weeks. Main erythema 600 rads 10 days. Permanent epilation 700 rads 3 weeks. Dry desquamation 1,000 rads 4 weeks. Invasive fibrosis 1,000 rads --- Dermal atrophy 1,100 > 14 weeks. Telangiectasis 1,200 rads > 52 weeks. Moist desquamation 1,500 rads 4 weeks. Late erythema 1,500 rads 6-10 weeks. Dermal necrosis 1,800 rads > 10 weeks. Secondary ulceration 2,000 rads > 6 weeks.
A Set of Sensible Guiding Principles from the FDA
There are probably some people who regard advice from the FDA as unnecessary, since they already know what needs to be done, and some really do. And others clearly do not. Gratefully, we compliment the FDA officials for producing a most valuable set of "General Principles and Recommendations for Facilities in Which Invasive Procedures Are Performed" (FDA 1994, pp.4-5). We reproduce an abbreviated version, below, and call attention particularly to Points 2 and 4:
- Point 1. "Establish standard operating procedures and clinical protocols for each specific type of procedure performed. The protocols should address all aspects of the procedure, such as patient selection, normal conduct of the procedure, actions in response to complications and consideration of limits on fluoroscopy exposure time ..."
- Point 2. "Know the radiation dose rates for the specific fluoroscopic system and for each mode of operation used during the clinical protocol ... Calibrate and document radiation output. Record information permitting estimation of the absorbed dose to skin in the patient's medical record."
- Point 3. "Assess the impact of each procedure's protocol on the potential for radiation injury to the patient ... Counsel patients regarding the symptoms and risks of large radiation exposures and address risks from radiation in the consent form. Justify and limit the use of high dose rate modes of operation."
- Point 4. "Modify the protocol, as appropriate, to limit the cumulative absorbed dose to any irradiated area of the skin to the minimum necessary for the clinical tasks, and particularly to avoid approaching cumulative doses that would induce unacceptable adverse effects. Use equipment which aids in minimizing absorbed dose with such features as: Indication of cumulative fluoroscopic exposure time. Indication of cumulative absorbed dose to the skin or a related quantity such as dose-area product. Real-time indication of dose rate or related quantity. "Last image hold" or "freeze frame" image display ..."
- Point 5. "Enlist a qualified medical physicist to assist in implementing these principles in such a manner so as not to adversely affect the clinical objectives of the procedure."Part 4. Our Own Recommendation about Solving This Problem
If we put radiation therapies aside, it is very likely that fluoroscopy is the most important and least documented radiation procedure today, in terms of cumulative exposure. One might assume that good records are generally being kept of the fluoroscopic radiation dose to patients, broadly. We do not see evidence that this is the case, especially outside radiologic offices. Yet, to record such information is a requirement, if anyone is ever to know whether medical practice is moving in the right direction on controlling dose in future years --- or in the wrong direction.
The serious problem of high radiation doses delivered by fluoroscopy certainly did not originate with the advanced procedures listed by the 1994 FDA Advisory. Similar problems were addressed by Dr. Braestrup, Dr. Buschke, Dr. Leddy, Dr. Parker, Dr. Pfahler, Dr. Taft, and by others in the 1920s, 1930s, 1940s and beyond (see Chapter 31).
Each generation of new physicians undertaking work in a particular specialty seems to regard roentgenologic hazard as a problem of the past. The assumption apparently is made that roentgenology can be regarded as just a tool in their ever-changing specialty --- not a part which demands their meaningful attention, comprehension, and accountability. That sort of dangerous assumption, to the extent it exists, will result in unnecessary cancers of the breast and other sites.
Possibly the most sensible place for alerting physicians in diverse specialties about the fluoroscopy problem is in the medical curriculum. Do medical schools give all future physicians sufficient warning that roentgenology is a tool which can be very useful, but which seems to return again and again to bite the medical professional in a most unpleasant manner? Future physicians are entitled to receive proper instruction about the unnecessary and unacceptable production of radiation-induced breast-cancer (and other cancers) which will result if they have inadequate respect for one of the major ways of rapidly building up serious radiation dose.
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- Confirmation from Another Source
Fluoroscopy was and still is a major source of non-recorded radiation doses --- almost certainly the major source today.
The uncertainty about fluoroscopic doses is a fact which is acknowledged in the most recent report of the United Nations Scientific Committee on Effects of Atomic Radiation, UNSCEAR 1994. That Committee attempted to estimate current average doses from diagnostic medical irradiation in over 20 countries, but it reported difficulty.
According to UNSCEAR 1994 (p.25): "One cause of uncertainty in these values is the use of fluoroscopy. This procedure results in much higher doses than those from radiography, and its prevalence is both uncertain and changing with time." (No other cause of uncertainty was mentioned.)
To locate discussions of non-recorded radiation doses in this book, see the Index under "Non-recorded radiation doses."