Putting radiation in perspective

The images of the destruction in Japan from last week’s major earthquake and tsunami have been horrifying. But as wrenching as they are, at least we can see them. Not so with radiation that may be leaking from a quake-damaged nuclear power reactor.

Radiation is like a stealth warrior. You can’t see, hear or feel it. Those with the highest and most immediate exposure, such as nuclear power plant workers, tend to show the effects within hours, days or weeks. But for most of the population, the health effects from lower-level exposure might not manifest themselves until 20 or 30 years later.

Rather scary? Well, yes. Here are a few facts, however, to help put things in perspective: The radiation risk to the Japanese public is low, at least for now. People can limit their exposure further simply by staying indoors. The health risk from radiation exposure depends on the type of radiation, the amount and length of exposure, as well as one’s cumulative lifetime dose.

From a New York Times article explaining the potential effects of radiation exposure from the disaster in Japan:

The more likely risk for the public is that of low-level exposures, which can increase the risk of cancer many years later. Again, the danger depends on the length of exposure and what types of radioactive materials to which one is exposed.

Some radioactive materials are readily absorbed by the body and linger there. Iodine, for example, goes to the thyroid gland, and strontium to the bone, and they emit radiation inside the body that over time can lead to cancer or leukemia. Other radioactive materials, like tritium, pass quickly through the body.

The article also notes that one of the main long-term risks isn’t from direct exposure per se. It’s from radioactive fallout that can enter the food chain, contaminating streams and offshore ocean water, for instance, or orchards, vegetable gardens and pastures.

Although many people are frightened of radiation, there’s an important point to keep in mind: We’re all exposed to radiation every day, primarily from natural and background sources. And for the average American, the single biggest source of exposure isn’t from nuclear power plants or clouds of radioactive fallout; it’s from medical imaging. Experts have calculated that CT scans and nuclear medicine account for more than one-third of the total radiation exposure and three-fourths of the medical imaging radiation exposure among the U.S. population.

How much radiation do you think you absorb on a daily basis? Here’s an online calculator from the EPA that helps you estimate your risk. (You’ll need to know the local altitude; Willmar is about 1,100 feet above sea level.) You can also keep track of your lifetime dose of medical-related radiation with this calculator from Xrayrisk.com, a site sponsored by the American Society of Radiologic Technologists. It includes the basics such as chest X-rays and dental X-rays, along with CT scans, nuclear medicine and interventional procedures. For more information on therapeutic radiation involved in cancer treatment, click here.

Photo: Associated Press

Radiation treatment gone wrong

It’s the kind of story that can’t help but be compelling:

As Scott Jerome-Parks lay dying, he clung to this wish: that his fatal radiation overdose – which left him deaf, struggling to see, unable to swallow, burned, with his teeth falling out, with ulcers in his mouth and throat, nauseated, in severe pain and finally unable to breathe – be studied and talked about publicly so that others might not have to live his nightmare.

Sensing death was near, Mr. Jerome-Parks summoned his family for a final Christmas. His friends sent two buckets of sand from the beach where they had played as children, so he could touch it, feel it and remember better days.

Mr. Jerome-Parks died several weeks later in 2007. He was 43.

A New York City hospital treating him for tongue cancer had failed to detect a computer error that directed a linear accelerator to blast his brain stem and neck with errant beams of radiation. Not once, but on three consecutive days.

The story, titled “Radiation Offers New Cures, and New Ways to Harm,” appeared Sunday in the New York Times and has generated some intense online discussion and blog commentary.

Therapeutic radiation is commonly used to treat cancer; more than half of all people diagnosed with cancer will at some point receive radiation therapy. The technology has come a long way over the past couple of decades. Treatment is typically more targeted than it used to be, so healthy cells can be spared the collateral damage of radiation exposure. Refinements such as intensity-modulated radiation therapy, or IMRT, also are increasingly being offered to patients.

But it carries its own set of risks – risks that patients are often uninformed of, and that may not be adequately addressed by the industry. Furthermore, the increasing use of complex equipment, software and treatment protocols is raising the danger that errors will occur and patients will be harmed, the New York Times explains:

“Linear accelerators and treatment planning are enormously more complex than 20 years ago,” said Dr. Howard I. Amols, chief of clinical physics at Memorial Sloan-Kettering Cancer Center in New York. But hospitals, he said, are often too trusting of the new computer systems and software, relying on them as if they had been tested over time, when in fact they have not.

Regulators and researchers can only guess how often radiotherapy accidents occur. With no single agency overseeing medical radiation, there is no central clearinghouse of cases. Accidents are chronically underreported, records show, and some states do not require that they be reported at all.

Many readers who commented on the story were appalled. “I could not finish reading this piece. It was an eternity of agony, even to get halfway through the narrative,” one person wrote. “Horrifying,” wrote someone else.

I count at least five separate and significant issues explored in the article and in the accompanying pieces: 1) the inherent risks of medical radiation; 2) the potential for medical devices to fail, especially as they become increasingly complex; 3) staff competence; 4) appropriate safeguards, checks and balances to ensure patient safety; 5) public accountability by the health care industry to investigate and prevent errors such as the one that killed Scott Jerome-Parks.

Although there’s been increasing focus on the risks associated with radiation exposure from routine CT scans and X-rays, I question whether it’s a fair comparison to therapeutic radiation. Radiation therapy has a specific intent, to treat cancer, so a whole different set of issues comes into play when making decisions whether to subject a patient to therapeutic radiation. Obviously, the amount of radiation required to target a tumor is also far greater and exposes the patient to significantly more radiation than any CT scan, albeit for the purpose of treating a serious disease. It can be a difficult tradeoff for cancer patients, who must weigh the potential risks of radiation treatment against the likelihood of the benefit.

If I were a cancer patient, I’m not sure how I would react to the New York Times story. Indeed, a number of commenters accused the reporting team of sensationalizing the issues and possibly scaring patients into making wrong-headed decisions. One person wrote:

While it is important to appreciate errors in medicine and swiftly correct them, particularly in an age of increasingly complex and computerized equipment, this article does a very effective job at frightening readers, particularly those with a personal experience of cancer therapy. The impression the reader takes is that there is gross negligence running rampant throughout radiation oncology departments as a matter of course. The article fails to mention the quite rigid quality assurance regulations in place for hospitals and physicians at the state and federal levels. This is a highly regulated field – not one of no oversight.

The American Society for Radiation Oncology issued its own statement this week, asserting that radiation therapy is still safe and effective and that errors are rare. A science blogger and cancer researcher offers his own take, drawing parallels between radiation therapy safety and surgical safety:

Reducing medical errors that harm patients is about more than just physicians. It’s about the whole system. In surgery we have been discovering this (and struggling with it) over the last decade or so. It’s not enough to just target the physicians. In my specialty and in the operating room, it’s necessary that everyone be involved, from the nurse who sees the patient when he comes in, the physicians who do the surgery, the scrub techs counting instruments, the scrub nurse verifying surgical site – in essence everyone involved with the care of the patient from the moment he shows up for surgery to the moment he either goes home or is admitted to the hospital. Radiation oncology has at least as many people involved in the care of the patient, if not more: nurses, radiation physicists, radiation oncologists, technicians operating the machinery. Moreover, because unlike surgery radiation is often given in small fractions over many visits, there are many more opportunities for error than in surgery.

Ultimately, I think the reporting by the New York Times has done a major favor on behalf of patient safety. At one time, chemotherapy errors were rarely publicized and efforts to make this form of cancer treatment safer were occurring mostly in piecemeal fashion. This all began changing in the mid-1990s, after the death of Boston Globe reporter Betsy Lehmann, who mistakenly received a lethal overdose of a chemotherapy drug. There’s now much greater awareness within the oncology community about medication safety, and a growing body of literature on chemotherapy administration procedures that have been shown to be safe and effective.

I’m not sure if this has been happening in radiation oncology to the same extent. A good start would be to develop a set of quality criteria – and to share them with the public, so patients and families can be better informed and in a better position to ask questions and advocate for themselves if something doesn’t seem right. It’s also essential to report errors and close calls in order to analyze what happened and redesign processes or systems to make them safer. After all, if you aren’t tracking mistakes, it’s nearly impossible to gauge how often they occur and what the contributing factors might be. Finally, there appears to be a need for more oversight – not just of hospital programs but of how the equipment and software are designed and manufactured and how the people who operate it are trained.

Injuries and deaths related to radiation therapy might be rare, but this is small comfort to patients and families who’ve had it happen to them. Surely the industry owes it to these people to do its best to be safe and accountable.

Photo: linear accelerator, Wikimedia Commons

The fallout zone

The headlines earlier this week were rather startling: Radiation from medical imaging, particularly from CT scans, might be exposing people to unnecessary risk and contributing to an increased likelihood of getting cancer.

The news appeared in the latest edition of the Archives of Internal Medicine. In an accompanying editorial, the question was raised: Although computed tomographic scans have aided greatly in visualizing the interior of the body, have we become so carried away with the benefits that we’re minimizing the risks? From the editorial:

Every day, more than 19,500 CT scans are performed in the United States, subjecting each patient to the equivalent of 30 to 442 chest radiographs per scan. Whether these scans will lead to demonstrable benefits through improvements in longevity or quality of life is hotly debated. What is becoming clear, however, is that the large doses of radiation from such scans will translate, statistically, into additional cancers. With CT scan use increasing annually, it is imperative that clinicians take into account the radiation risks when assessing the benefits to their patients.

Two new studies published in this week’s Archives of Internal Medicine underscore the point. One of these studies attempts to quantify the future risk of cancer from CT scan exposure, using 2007 as a baseline and analyzing the risk based on age, gender and type of scan. The conclusion: As many as 29,000 future cancers might be related to the use of CT scans. The risk appeared to be higher for CT scans of the chest and abdomen, and for patients who were younger.

Some interesting figures from this study: Approximately one-third, or 35 percent, of the projected cancers from CT exposure were among the 35-to-54-year-0ld age group. Since there’s a long latency – as much as 20 to 30 years – between radiation exposure and the potential development of cancer, it stands to reason that exposure from CT scans would pose a higher risk to younger people whose life expectancy is comparatively longer. Lung cancer was the most common projected cancer, followed by colon cancer and leukemia. Women also appeared to be at higher risk, possibly because they have a higher frequency of CT scans than do men.

There’s also dose, scan type and technology to take into account. The second study published in the Archives of Internal Medicine examined CT scans done at four institutions in California last year and found that, depending on the scan and the equipment, the amount of radiation varied by anywhere from 6-fold to 13-fold. Whole-body scans, for instance, subject the patient to more radiation than more limited scans. The researchers also found that in many cases, the radiation amount was substantially higher than previously thought. "It is important to understand how much radiation medical imaging delivers, so this potential for harm can be balanced against the potential for benefit," the study’s authors wrote.

Do consumers need to worry? I admit to cringing over some of the alarmist headlines that have appeared this past week: "CT scans blamed for surge in cancers." "CT scans more dangerous than previously assumed." "Thousands of new cancer diagnoses predicted, due to soaring use of CT."

It’s true that CT scans deliver considerably more radiation than the average X-ray. It’s also true that this form of medical imaging is widely used and is to some extent overused.

But concern over radiation exposure from medical imaging is by no means a new issue. Multiple studies have documented that there has always been some level of risk. This study, for instance, addresses the safety of doing CT scans of the head among children. Here’s another study that takes a look at the use of CT scans for detecting coronary artery calcification among asymptomatic adults.

Some caution also is warranted in interpreting the statistics contained in the Archives of Internal Medicine study. First of all, the projections are the result of computer modeling, not actual cases. Secondly, even if the projections are accurate, they still represent only 1.5 to 2 percent of new cancers diagnosed annually in the United States.

None of this should be taken to mean that CT scans are dangerous or that people should stop having them. The American College of Radiology weighed in this week with its own statement, pointing out that medical imaging has greatly improved the ability to diagnose disease and injury and is far cheaper and less invasive than surgery.

What it seems to come down to is whether the technology is being used appropriately. From the ACR’s statement:

The American College of Radiology advises that no imaging exam should be performed unless there is a clear medical benefit that outweighs any associated risk. The ACR supports the "as low as reasonably achievable" concept which urges providers to use the minimum level of radiation needed in imaging exams to achieve the necessary results.

This message of moderation is one we’ve been hearing rather often lately, first with mammography and cancer screening, and now with CT imaging. While it might be confusing and possibly alarming to people, overall it’s not a bad thing to insert these issues into the public discussion. Medical intervention often involves a balance between benefit to the patient and potential risks. The more we understand that it’s not entirely risk-free, the better we’ll be able to make good decisions.