Semelka's Spin: Pathways to Imaging Excellence
Roentgen's Real Legacy, In the Age of Informed Consent

Richard C. Semelka, MD; Suzanne Ronald, MD


July 06, 2006

Recently I had an article emailed to me for consideration for Semelka's Spin that was written by a first-year medical student at the University of Manitoba, Canada; this student is planning to pursue a career in diagnostic radiology.

She has written an interesting historical piece on radiology, beginning with Wilhelm Roentgen. I think this piece offers a fascinating historical perspective on the field of radiology and why imagers have, to date, been reluctant to discuss with patients in detail the dangers of radiation associated with medical x-rays.

History of Medicine X:
Diagnostic Radiology and the Principle of Informed Consent

With his discovery of x-rays in 1895, Wilhelm Conrad Roentgen fathered the field of diagnostic radiology. In that era of medicine, informed consent was not part of the medical lexicon; however, in light of our current appreciation of the patients' right to know the consequences, or potential consequences, of treatment, we must look toward providing patients with information on the potential risks inherent in x-rays.

While conducting some laboratory experiments on November 8, 1895, Roentgen, then a 50-year-old, well-known scientist and Professor of Physics at the University of Wurzburg, saw the effect of an unknown and remarkable phenomenon. He investigated this effect in a precise and thorough manner and discovered it to be attributable to "a new kind of rays." After 7 weeks of working tirelessly, during which he sequestered himself in his laboratory, on December 28, 1895, he presented his findings in a written report, the classic "Preliminary Communication."[1] Although it had not been read before a meeting, this report was accepted for publication in the Annals of the Physical Medical Society of Wurzburg. Within a few days, the news of the new rays dispersed widely, and people from many nations rushed to glimpse this enchanted world on January 23, 1896, when this modest pioneer spoke publicly of his discovery for the first time. After this lecture before the Physical Medical Society of the University of Wurzburg, the famous anatomist, von Koelliker, dubbed the new phenomenon as "Roentgen's rays," and a tremendous amount of work with the new rays was begun.[1]

The mind of Roentgen, the scientist, is impenetrable in the moments immediately following his great discovery. For the first few days after the initial observation, he rarely verbalized his thoughts. The scientist ate and slept in his laboratory in order to further investigate, undisturbed, his observations of the fluorescent crystals. Roentgen's two senior assistants, one of whom helped to evacuate the Hittorf tubes, were kept in the dark, and with the publication of the "Preliminary Communication," learned for the first time about the important discovery made in their institution. Such was the tradition of silence.

In the early days of x-rays, except for patients who underwent serial chest x-rays for tuberculosis, the people who sustained the greatest x-ray exposure were the imagers themselves and their accomplices – hence, the term "Radiology Martyrs" for those who died of radiation-induced cancer while investigating x-rays. Tragically, Roentgen's own wife, whose hand is pictured in the first x-ray photograph, died a gruesome radiation sarcoma death.

Thomas Alva Edison was among the first to act on the news of Roentgen's discovery. Seeking to find practical use for the x-ray phenomenon, he utilized what has been dubbed his greatest invention – the industrial laboratory. Edison provided the basis for the field of fluoroscopy by constructing a device he eventually called the "fluoroscope," which was proposed for domestic use. When his assistant, Clarence Dally, developed burns on his skin that preceded development of a radiation-induced malignant neoplasm, Edison was alerted to the power of x-rays to cause damage to the body. With Dally's death, America now had its first martyr to x-rays.[2]

In the early days of x-rays, radiologists performed a great deal of fluoroscopy, since this was the best approach to view internal structures in 3 dimensions. For every fluoroscopic study, the radiologists also received a lot of radiation and, consequently, the earliest occupational groups exposed to ionizing radiation were radiologists and radiologic technologists.[3] Among these early workers employed before 1950, when radiation exposures were high, an increased mortality due to malignancy was observed.[3] In the 1940s, there were a few articles reporting on the increased incidence of malignancies, especially leukemia in radiology practitioners.[3] An editorial that was written in 1977 by Irwin DJ Bross[4] lamented the rejection of his article on the hazards of x-rays (interestingly, in the pre-computed tomography [CT] era), and his view was that in the setting where some medical procedure may be hazardous to the public, the burden of proof for safety rests with the practitioners.

An important translation of Roentgen's work from laboratory investigation to clinical practice came in the 1970s with the development of the first commercial CT scanner by Sir Godfrey Hounsfield. Today, CT is the major source of medical radiation.[5] However, the diagnostic value of CT when used judiciously for specific indications is unquestioned. Evaluation of benign diffuse lung diseases, renal calculi, severe acute trauma, and tube and catheter assessments in sick patients are all best studied by CT. Recent advances in multidetector row CT technology create clearer images in shorter times, and have markedly increased the diagnostic value of CT.[6]

With the greatest amount of radiation delivered by CT, in which radiologists are not in the scanning room and technologists at the operating console are shielded by leaded glass, formerly radiologists shared in the radiation burden that they delivered to patients, but now only the patients get radiation – but typically without information disclosure. Medical radiation workers are currently exposed to minimal levels of radiation doses, where there is no clear evidence of an increased cancer risk to date[7]; however, this is not true of interventional radiologists.

Patients who undergo even individual CT examinations are not without risk. The findings in the seventh report in the series, Biological Effects of Ionizing Radiations (BEIR VII), reveal a 1/1000 chance of developing a fatal cancer from 10 mSv[8] – the equivalent radiation dose of 1 CT of the chest or abdomen. The risk increases if radiation is delivered to organs or tissues that are more sensitive, including the thyroid, breast, bone marrow, gastrointestinal tract, and regions of wound healing or tissue repair. The areas of wound healing and tissue repair provoke an ethical dilemma since these areas seem likely to be imaged. A higher incidence of leukemia and a spectrum of solid cancers, including breast, digestive organs, colon, thyroid, and lung, results from exposure to radiation.[8,9,10,11] Understanding of latency period for development of malignancy should also guide the use of CT, and the ages at which it is of greater risk (pediatric patients) and of minimal risk (elderly patients) should be considered. The latency period for developing leukemia is 2-5 years following radiation exposure, and for solid tumors, 10-20 years, although the risk that leukemia will develop persists throughout life.[8,11]

'The doctor knows best' maxim, and the legal term 'implicit trust,' best describe how patients allowed doctors to make decisions for them prior to the 1960s. With the evolution of mass communication during the 1960s, patients started to become more proactive in their own healthcare. Patients are more eager to find out what is wrong with them with no waiting period and are demanding high-technology investigations such as CT. As physicians, we have been happy enough to oblige this, also wanting to know what is going on and viewing CT as the imaging physical exam. With the recognition of the potential deleterious effects of radiation mediated by CT, physicians are now learning that, despite its availability, technology should not always be used.

'Informed consent' is the term used to describe the accepted precursor to action on the part of the physician, and its development as a principle of ethics in medicine can be linked to the Nuremburg Code, which arose from the Nuremburg Medical Trials by the International Scientific Commission on War Crimes.[12] The 3 linchpins of informed consent are as follows: full information disclosure, mental capacity to decide, and absence of coercion. Explaining the risks and benefits of options so that patients can make the most informed decisions possible is one of the most important roles of the physician. In some cases, physicians must walk the fine line between enough information to educate but not too much so as to frighten the patient; however, the agreed-upon standard of care is that information disclosure should include prognosis, the risks, benefits, and probability of success for each treatment option (including the option for no treatment). In practice, it is always difficult to determine just how much information is enough, which is why, in the case of CT scanning, patients are often not given full information disclosure.

There are 2 commonly accepted standards to guide physicians on how much information is enough for patients. The 'reasonable person' standard advises that physicians need to tell only enough for a 'reasonable person' to decide. Since perceptions of 'reasonableness' and 'reason' differ among individuals, clearly this standard is flawed, though still a valuable guideline. The 'professional' standard advises physicians to disclose only what their colleagues would disclose to a patient. This standard is also imperfect because it does not account for the variability between physician practices. It has been suggested that perhaps the best option is to combine the two standards and tailor information to the needs of individual patients. Whatever guideline or combination is employed, it is clearly a liability to the physician to circumvent the principle of informed consent altogether.

The era in which Wilhelm C. Roentgen, father of the field of diagnostic radiology, lived with its identifiable tradition of silence, did not lend itself to the disclosure of information. We must act toward grafting the principle of informed consent to the practice of radiology.