As radiation therapy becomes increasingly complex for technicians to operate, experts grapple with whether the risks outweigh the benefits for patients
The future has arrived. In the last decade, radiation technology has exploded, creating a complexity of scanning systems that are more sophisticated than ever before. On one hand, providers can offer patients more precise treatment than they once could. But, experts are finding that better healthcare sometimes comes at a high price.
Recent media attention highlighting the dangers of overradiation and improperly calibrated linear accelerators, followed by a congressional hearing in February by the House Energy and Commerce Committee’s Subcommittee on Health, have stirred up much discussion regarding the fine balance between heath care and health hazard. “The articles in the New York Times raised a red flag with Congress,” says James Hevezi, Ph.D., FACR/FAAPM, American College of Radiology Board of Chancellors, Commission of Medical Physics Chair, Director of Medical Physics, CyberKnife Center of Miami, Fla. Today, experts are “at the beginning” of a long process of establishing more effective safety guidelines and standards, he explains.
Indeed, when the Subcommittee on Health convened to examine the potential benefits and risks of the use of radiation in medicine, it drew much attention from hospital administrators, medical physicists, radiation therapists and technology experts to the issues at hand. “The benefits that we as a society have gained from advancements [in radiation therapy] are enormous,” said chairman Frank Pallone, Jr. “But, we often forget the fact that we are still dealing with something that is toxic to the human body. When it is delivered correctly, a single CT scan can deliver as much radiation as 300 chest X-rays. With operating technology as powerful and dangerous as this, it is even more crucial that quality and safety are always front and center.
“With all the advancements the industry has made, these technologies have become more complex and complicated to operate,” he continued. “It is shocking to me that in many states, individuals who operate these devices do not need to be licensed and are therefore not regulated at all in terms of education and expertise.”
“We have professional societies that make [safety] recommendations, but errors still occur,” says Hevezi. “There are no uniform training or requirements for certification of the radiation technicians who push the button [to deliver] radiation therapy or for the technologists operating computed tomography (CT) scanners.” In fact, to date, only four states license their radiation therapists, he points out. “Professional associations should make recommendations of practical training, and manufacturers should ensure that the equipment is properly accredited and calibrated.” In addition, there needs to be a central repository for reporting inspection results of radiation therapy machines, he points out.
Radiation safety comes down to a multifaceted effort on the part of hospital administrators, medical physicists who consult to the radiation department, and the radiologists, says Hevezi. “They all are responsible for [the safety of their patients], and the equipment manufacturers should be responsible for training them properly.”
The concerns, risks
Potentially dangerous exposure to radiation can occur during radiation treatment for cancer, as well as diagnostic imaging procedures, according to Jason Launders, MSc, senior project officer, medical physicist, ECRI Institute. “In radiation therapy, there [must always be] a balance between the likelihood of a cure and the [potential] damage to healthy tissue,” says Launders. Short-term effects include hair loss and skin burns (cells are killed), although the dead cells eventually will rejuvenate assuming a sufficient number of cells remain unaffected. It takes “a relatively high dose” of radiation to damage healthy tissue, he points out. Still, “it can occur in imaging studies, particularly with fluoroscopically-guided interventions.”
For an 18-month period beginning in February 2008, more than 200 stroke patients at Cedars-Sinai Medical Center in Los Angeles were overdosed with radiation during CT brain perfusion scans. The problem wasn’t detected until a patient told the hospital he had experienced some hair loss after a scan. “The dose rate limits and monitoring [checks and balances] built into modern fluoroscopy equipment are designed to reduce this risk,” says Launders. “But, the risk cannot be eliminated and depends on the physician’s skill. This is a major concern in every radiation treatment.”
When it comes to low-level radiation exposure through diagnostic imaging, “the problem is that we really don’t know what the risk is,” says Launders. “The conservative assumption is that any radiation dose is associated with a risk of causing cancer. As the dose increases, the risk increases proportionately.”
However, some experts believe that small levels of radiation are beneficial, and that the benefits outweigh the risks, he notes. The bottom line is, “the available data is limited, so we cannot be sure. So, in diagnostic imaging, the principle is that the patient will benefit more than the cancer risk. But, we cannot provide definitive answers, and the uncertainty [tends to] increase anxiety in patients. [So], we reduce the dose in diagnostic imaging to minimize the associated cancer risk.”
A major concern over radiation safety is that of damage to patients’ DNA by ionizing radiation. Actually, “DNA is damaged by ionizing radiation every day as background radiation passes through us,” says Launders. “Events occur thousands of times every day. Most of the DNA will be repaired without further concern.” Even when the repair process fails, and the DNA is no longer tenable, there still are no further problems to the individual, he notes. “However, when the DNA repair contains errors (e.g., it is mutated), that’s when problems occur.”
Some experts are particularly concerned about the safety of CT scans, he points out. “The chances of [DNA] mutating into a viable structure are very small, but this is believed to be the first step in carcinogenesis,” he explains. And while scientists are not in complete agreement over what constitutes a dangerous level of radiation exposure, many believe that reducing exposure is the primary means of reducing patients’ risk of developing cancer.
That said, physicians appreciate that imaging often helps reduce uncertainty around patient diagnoses, he continues. “However, many physicians do not understand the risks of radiation exposure and relative dose of different modalities,” says Launders. “The highest doses come from certain nuclear medicine and cat scan studies. In general, the high-dose modalities provide more diagnostic information, while some modalities, such as ultrasound and magnetic resonance imaging (MRI), have no ionizing radiation dose. If possible, these should be used.” Unfortunately, they can’t always provide the information needed and may be contraindicated, he notes.
“So referring physicians (particularly those who are not radiologists) need to be educated. The American College of Radiology has published appropriateness criteria to help address this question. It is always a clinical decision – one that should be answered by the referring physician.”
Patient safety should always be the primary concern in any radiation therapy, says Launders. “The goal of all technical innovations has been to target the radiation dose to as small a volume as possible to treat the tumor. It could be argued that the medical physicist’s primary function is to ensure the safety of treatment. However, humans are not infallible and errors do occur. Also, software problems lead to errors. Overdose to surrounding tissue is definitely a concern but equally important is under-dosing the tumor, since this can lead to an unsuccessful treatment.” In many cases, this is just as bad, he adds.
Taking on more and better
“Radiation therapy has become a way for hospitals to market themselves,” says Anthony Zietman, M.B.B.S., M.D., professor of radiation oncology, Harvard Medical School, president of the American Society for Radiation Oncology (ASTRO). As such, “they are under a lot of pressure to advertise that they carry the best technology. So, there is a tendency for them to take on more sophisticated equipment than they can support. Today, there are so many machines, and they all function differently. Yes, they have safety bells and whistles built in, but they still rely on a human to operate them. We need more medical physics support to understand, and keep up with, the new technology.
“Physicians and radiation therapists must be willing to [admit] when they are not equipped to handle the more sophisticated level of radiation equipment, and vendors must be willing to offer more training,” he continues. “The vendor [typically] provides two days of training, and then the radiology [technicians and therapists] are on their own. Hospitals need to negotiate for longer, and ongoing, training. We also need to push for a minimum level of medical physics support, and we need to see [the establishment of] a national error reporting system.”
Others, like Launders, believe that while manufacturers “have a part to play” in radiation safety, “the responsibility lies with the hospital, which needs to ensure its staff is suitably trained, qualified and credentialed.
“The medical physicist is responsible for calibrating the linear accelerator and any associated imaging equipment,” Launders says. “As precision and accuracy have increased, smaller [radiation] beams are being used. Greater care is needed when calibrating those beams. Also, the equipment is more sophisticated today, so calibration has become more complex.” So while advances in technology have led to improvement in precision and accuracy, there is more pressure than before for radiation therapists to keep up and adapt to changing processes, he notes. This calls for “the right experts and the right number of them,” he adds.
That said, every facility requires a different amount of vendor training, says Launders. “Some training is usually included in the cost [of the equipment],” he says, noting that this generally includes technical training. Often, more training is needed, as well as clinical training, he points out. “Negotiators must [work with] with clinical users to determine the amount of training really needed.
“The relationship between people and radiation equipment is a complicated one,” Zietman adds. As such, “everyone involved has a responsibility here.”