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Dangers of high-dose fluoroscopy. (Student Scope).

Over the years, the fluoroscope has been a valuable tool to diagnose and treat illnesses and injuries. It also has proven harmful to patients and radiation workers when used indiscriminately. Since 1992 the U.S. Food and Drug Administration (FDA) and its European counterparts have identified more than 115 cases of radiation skin injuries resulting from prolonged fluoroscopic diagnostic and interventional procedures. (1) In some documented cases, patients undergoing multiple procedures over short time periods were exposed to localized radiation skin doses that exceeded 20 Gy (2000 rad). (2)

The number of injuries may appear small when one considers that more than 700 000 fluoroscopic procedures are performed annually. (3) However, the long-term significance of exposing large numbers of patients and health care workers to high doses of radiation could have a drastic effect on future generations. To ensure that patients and radiation workers are not exposed unnecessarily to high doses of radiation, it is imperative for health care practitioners and radiologic technologists to be fully cognizant of the dangers of radiation and the proper use of equipment. Having a better understanding of the history, research findings, fluoroscopic working environment and radiation health care professionals' role is key to minimize exposure and prevent injuries to patients, coworkers and one's self.

History

During the 1980s, medical researchers began studying less traumatic methods to treat coronary artery disease in an effort to minimize healing time and reduce the length of inpatient hospital stays. Their research led to the development of fluoroscopy-guided angiography and angioplasty. In these procedures, a small catheter is introduced into a major blood vessel and guided, using a fluoroscope, to a location of interest. Then a contrast medium is introduced into the vessel to identify possible abnormalities. If a blocked artery is located, a small balloon at the tip of the catheter is inflated to open up the blockage and permit blood to flow without restriction. These procedures allow physicians to visualize and treat vascular diseases without performing open-heart surgery. Patients can be treated more rapidly, recovery periods are minimized and hospital stays are reduced from approximately 5 days to 18 hours or less. (4)

The number and types of diagnostic and interventional procedures have grown dramatically. For example, in 1987 approximately 450 fluoroscopy-guided interventions were performed in the United States. (5) In 2000 that figure had increased to more than 700 000. (1) As the number of procedures has increased, the incidence of reported injuries also has risen. More than 115 cases of radiation skin injuries to patients have been reported to regulatory authorities in the United States and Europe since 1992. (1) Additionally, a higher incidence of cataracts and radiation injuries to the hands of physicians performing these procedures also has been documented. (1)

New interventional techniques are developed every day. Given how quickly this area of radiology has grown and the rapid aging of the U. S. population, the number of annual procedures will possibly double or triple during the next 10 years. (R. Sumita, M.D., presentation on interventional radiology, Memorial Hospital, Santa Rosa, Calif, February 6, 2002.) This increase places the general public and radiation workers at greater risk to receive radiation doses that can lead to serious injuries, illnesses or premature death. Several experts who have studied incidents of radiation-induced skin injuries believe many cases go unreported. If their assessment is correct, an accurate evaluation of the future hazards of high-dose fluoroscopy is virtually impossible at this point.

Research Findings

The Safe Medical Devices Act of 1990 (SMDA) mandated that deaths, serious illnesses and injuries resulting from the use of medical devices be reported to the FDA. The act established the Center for Devices and Radiologic Health (CDRH), which is responsible for receiving incident reports, conducting thorough investigations and initiating corrective actions.

Between 1992 and 1993, the CDRH received reports of patients presenting with skin injuries that may have resulted from prolonged fluoroscopic procedures. On September 20, 1994, the FDA issued a nationwide public health advisory, Avoidance of Serious Skin Injuries to Patients During Fluoroscopically-Guided Procedures. The advisory stated that the CDRH had information concerning severe radiation-induced skin injuries to patients following diagnostic and interventional fluoroscopic procedures. The document also identified specific high-dose fluoroscopic procedures that could be harmful and reinforced the SMDA requirement to report injuries to the CDRH. (5,6)

The FDA public health advisory heightened awareness of radiation-induced skin injuries among practitioners and led to an increase in the number of reported incidents. Attempting to identify the source of the problem, the CDRH prepared a scientific paper on 26 radiation-induced injuries that were reported between January 1992 and October 1995. The paper, Radiation-Induced Skin Injuries from Fluoroscopy, was presented in 1995 at the 81st Scientific Assembly and Annual Meeting of the Radiological Society of North America. The scientific data and graphic pictures of a patient's radiation-induced skin injury stunned many of the attendees. Immediate outcomes of the presentation included:

* Nongovernment professionals studying the effects of high-dose radiation procedures.

* Practitioners taking steps to reduce patient dose.

* Manufacturers developing safer equipment.

* State radiologic health branches establishing training and certification programs.

This landmark paper was published separately in the September 1996 issue of Radiographics and often is cited as an important source of information concerning radiation-induced skin injuries. (5)

In 1997 the Mayo Foundation and Clinic in Rochester, Minn, initiated a study to accurately assess the radiation exposure received by patients undergoing cardiac catheterization diagnostic and interventional procedures. During an 8-week period, x-ray exposure measurements were conducted for 972 patients who underwent 992 diagnostic and interventional coronary angiography and percutaneous procedures. Of the procedures performed, 706 were diagnostic and 286 were interventional. The average exposure for the 992 procedures was 1.62 Gy (162.1 rad). When further broken down, the average exposure for diagnostic procedures was 1.35 Gy (135.3 rad), and for interventional procedures it was 3.71 Gy (370.5 rad). (7)

In evaluating the radiation dose these patients received, one must keep in mind that the primary x-ray beam generally is limited to a very small field vs a whole-body exposure. This is important because whole-body doses of 0.05 Gy (5 rad) to 1 Gy (100 rad) delivered over a short period of time are the lowest doses that can result in chromosomal aberration or death in human beings, respectively.8 Additionally, local doses as low as 0.1 Gy (10 rad) can cause gonadal dysfunction. Because many of these procedures start by inserting a catheter in the femoral artery and then guiding it under fluoroscopy to the target organ in the abdominal or thoracic cavity, the gonads are highly likely to receive a certain amount of the primary beam, as well as scatter radiation.

Since 1996 additional studies have been conducted, reports have been published, professional seminars have been presented and training and certification programs have gone into effect. These initiatives have helped increase awareness of radiation-induced injuries for both health care professionals and the public. Continued research into the hazards of high-dose fluoroscopy and ways to overcome these dangers is paramount to guarantee the viability of these lifesaving procedures. Additionally, ensuring that health care professionals and the general public are aware of the risks and advantages can help minimize unnecessary radiation exposure.

Changing Work Environment

Before the 1990s, radiologists and radiologic technologists were the primary players in the fluoroscopy suite. Radiation physicists played a major role in equipment design and construction, as well as radiation safety. Practitioners in each of these specialties received in-depth training in radiation safety and fluoroscopy to ensure patient and worker safety..

As technology advanced, more medical specialists turned to fluoroscopy to assist in diagnosing and treating patients. Today it is common for physicians from a wide variety of medical and surgical specialties to perform diagnostic and interventional procedures in the fluoroscopy suite. Nonradiology specialists may have only limited radiation safety training and, therefore, may not be fully cognizant of the dangers fluoroscopy can pose to the patient and the practitioner.

These specialists work closely with radiologic technologists on a daily basis to perform the procedures. This has placed the radiologic technologist in the position of being the on-site expert, with technologists assuming an additional responsibility for ensuring that the fluoroscopic procedures are performed in a safe manner.

As the number of nonradiology specialists using fluoroscopy increases, radiation safety and fluoroscopic certification programs must be put into place to ensure the safety of patients and radiation workers. To this end, certain states have mandated that practitioners using fluoroscopy in their practices must attend courses and obtain state certifications. In locations that are not state regulated, some health care organizations have implemented their own training and certification programs. In other cases, specialists attend seminars or participate in rotations in radiology departments to hone their skills and knowledge. Continuity in training and certification has yet to be achieved, but with continuing pressure from professional radiological societies, mandatory training and certification in the use of fluoroscopy may one day be realized.

Radiation Health Care Professional's Role

The most important thing professionals can do is participate in training programs that provide the required education and skills to conduct safe examinations. (1) Encouraging others to seek additional training and to comply with procedural protocols can help minimize radiation exposures in the fluoroscopy suite. Before using any equipment, the operator should receive formal training to ensure he or she fully understands how to operate the equipment safely, efficiently and effectively. (1) Workers can maintain competency and an awareness of the dangers of radiation exposure by reviewing articles.

Several techniques, such as using optimal kilovoltage peak (kVp) and the lowest possible milliamperage (mA), can significantly reduce radiation dosage to patients and practitioners. Whenever possible the fluoroscopist should increase the distance between the x-ray tube and patient's skin to reduce the skin dose and should decrease the distance between the image intensifier and the patient. The magnification mode significantly increases patient dose and should not be used unless absolutely necessary. Radiation doses for pediatric patients and small adults can be significantly reduced with minimal loss of contrast by removing the grid. Tight collimation of the x-ray beam can lessen exposure levels and generate a higher quality image. Keeping beam-on time to a minimum prevents unnecessary radiation dose to the patient, operator and other personnel. Using the last-image-hold feature cuts fluoroscopy time by keeping the last image on the monitor so constant fluoroscopy is not necessary. Using a pulsed beam instead of continuous beam fluoroscopy can reduce patient dose in half without causing any significant visual change in the fluoroscopic image. (1,9)

The cumulative time that the patient undergoes fluoroscopic procedures should be documented. The patient's medical history should be reviewed to ensure the patient hasn't undergone multiple procedures that could cumulatively cause skin injuries. The patient's dose should be entered in appropriate logs, and when required, entries also should be made in the patient's medical record. (1)

Radiation professionals who routinely work in a fluoroscopic suite should ensure that equipment is operating properly, supplies are not outdated and appropriate preventive maintenance and safety inspections are conducted. (1)

Conclusion

Patients and radiation workers are exposed to higher levels of radiation than ever before. Technology and an increasing number of diagnostic and interventional radiation procedures suggest that exposure levels will continue to rise. Radiation professionals and other specialists who use fluoroscopy must take steps to reduce exposure to the lowest possible levels. Failure to do so places both the patient and radiation worker at greater risk of injury or premature death. Education, awareness of the dangers of fluoroscopy and sound fluoroscopy practices are the keys to ensuring the health and well-being of patients and coworkers.

References

(1.) Archer BR. High dose fluoroscopy--the administrator's responsibility. Radiol Manage. 2002;24 (2):26-32.

(2.) Medical exposures--another look at risk vs benefit. Available at: www.acuri.com/medexpo. Accessed February 24, 2002.

(3.) Sternberg S. Angioplasty downside: radiation exposure. USA Today. November 20, 2000. Available at: www.usatoday.com/life/health/heart/1hhea160.htm. Accessed February 24, 2002.

(4.) Regush N. Medical radiation burns. Second opinion. ABC News Web site. April 20, 2001. Available at: www.abcnews.go.com/sections/living/SecondOpinion/secondopinion10423. Accessed February 24, 2002.

(5.) Shope TB. Radiation-induced skin injuries from fluoroscopy. Radiographics. 1996;16(5):1195-1199.

(6.) FDA public health advisory: avoidance of serious x-ray-induced skin injuries to patients during fluoroscopically-guided procedures. Food and Drug Administration Web site. September 30, 1994. Available at: www.fda.gov/cdrh/fluor.html. Accessed April 3, 2002.

(7.) Cusma JT, Bell MR, Wondrow MA, Taubel JP, Holmes DR. Real-time measurement of radiation exposure to patients during diagnostic coronary angiography and percutaneous interventional procedures. J Am Coll Cardiol. 1999;33(2):427435.

(8.) Bushong SC. Radiologic Science for Technologists: Physics, Biology, and Protection. 6th ed. St. Louis, Mo: Mosby; 1997.

(9.) Bailey ED, Pellingrini D. Syllabus on Fluoroscopy Radiation Protection. 5th rev. Sacramento, Calif.' California Department of Health Services Radiologic Branch; March 1996.

Patrick M. Parks, R.T.(R), graduated from the radiologic technology program at Santa Rosa Junior College in Santa Rosa, Calif, in July 2002. He is employed in the radiology department at Palm Drive Hospital in Sebastopol, Calif.
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Title Annotation:preventing radiation injuries
Author:Parks, Patrick M.
Publication:Radiologic Technology
Geographic Code:1USA
Date:May 1, 2003
Words:2196
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