Carole-Anne Stanway had lived with blinding headaches for 17 years before she decided enough was enough.
The grandmother of five in Kelowna finally asked her doctor for an MRI to see what was wrong. He refused to give her a referral, saying the headaches were just from tension. He had put her on Tylenol 3 and antidepressants, but those hadn’t helped.
Stanway got an MRI done privately anyway, at a cost of $2,700. The result: she had three meningiomas, a type of brain tumour.
The good news was the tumours weren’t cancerous. The bad news was the specialist didn’t want to remove them unless they became cancerous because of the risk of brain damage.
Stanway put up with the headaches for five more years until, in 2002, they and other health problems forced her to stop working as an assistant in a medical office. She’s been on disability leave ever since.
She has been prescribed a buffet of pain drugs, which, along with noninsured medical procedures and travel to see specialists, have drained her savings. The drugs reduced the pain for a while, but her body quickly got used to them. Then they didn’t help anymore.
She stopped taking the pain meds five years ago after they started to cause her kidney problems. Some of the drugs also gave her severe nausea. But she’s still on the antidepressants. “Chronic pain is difficult to deal with otherwise,” she said in a phone interview from her apartment.
A few months ago, her eyes started moving uncontrollably while she was reading, likely a side effect of meningioma, which can cause optic problems.
Stanway said doctors don’t know what caused her meningiomas, but she thinks dental X-rays are a possible culprit. “I had a lot of dental work done when I was younger. As children, we received a lot of radiation.”
In a study in the journal Cancer last year, 1,433 people with meningioma were found to be two times more likely to have had a “bitewing” dental X-ray as those without the illness. Those who reported having a panorex scanning dental X-ray (which gives a two-dimensional panoramic view of the mouth) before age 10 were 4.9 times more likely to have meningioma.
Meningioma is the most common form of primary brain tumour (tumours that start in the brain). Women get it more than twice as often as men.
Other studies have linked dental X-rays to thyroid cancer, breast cancer (in women who hadn’t worn a shielded apron), saliva-gland tumours, and glioma (a cancerous type of brain and spinal tumour).
Pregnant women who got a dental X-ray were three times more likely to deliver a low-birth-weight baby (weighing less than 2.5 kilograms), according to a 2004 study in the Journal of the American Medical Association.
Dental X-rays are the most common way Americans are exposed to human-made radiation, the 2012 Cancer study said.
Yet despite growing awareness about the risks of X-rays, radiation in many dental offices is actually rising. That’s thanks to the explosive growth of 3-D cone-beam CT (computed tomography) machines, which give off up to 60 times the radiation of a conventional dental X-ray.
CT manufacturers heavily market their machines to dentists, promising unsurpassed detail about a patient’s mouth. The marketing includes payments to prominent dentists to give talks to colleagues, ads in dental magazines and displays at dental conferences, according to a 2010 New York Times investigation.
“Kids love to see that 3-D image,” one orthodontist said in a webcast sponsored by a CT maker.
The marketing often minimizes the radiation exposure from the machines, while experts on dental radiation criticize the growing “indiscriminate use” of CT scans for routine screening, particularly by orthodontists, the story said.
“The parents of these children have no idea about the amount of radiation used in these CT scans, and even more frightening, neither do the dentists,” Nicholas Dello Russo, an instructor in periodontology at Harvard University’s school of dental medicine, told the Times.
Here in B.C., the first CT machine was introduced in a dental office in 2006 or 2007. Today, five to 10 percent of dental offices use one, according to Daniel Hanson of Langley-based Innovative Biomedical Engineering.
Hanson’s company is hired by the B.C. Dental Association to inspect dentists’ X-ray machines to ensure they comply with radiation safety regulations. That doesn’t include looking at patients’ radiation-exposure records, which Hanson said no one in the province is tracking.
Hanson helped spearhead provincial CT-machine guidelines that came out last November. Previously, no federal or B.C. standards had existed for the machines.
“There was inconsistency in the way people were interpreting the risk from CT machines. This whole technology just exploded on the industry,” Hanson told the Georgia Straight in a phone interview while on vacation.
The increasing use of dental CT scans is part of a trend of patients being exposed to increasing amounts of other medical X-ray radiation. In the U.S., radiation exposure from diagnostic medical X-rays has shot up more than sevenfold for the average person since the early 1980s, in large part because of the use of medical CT machines, according to a 2009 study by the U.S.-based National Council on Radiation Protection & Measurements.
An estimated 29,000 cancers (half of them fatal) will result from the 72 million medical CT scans done in 2007 alone, the U.S. National Cancer Institute said in a different 2009 study.
Yet only nine percent of emergency-room doctors believe CT scans increase cancer risk, and only three percent of patients think so, according to a 2004 study in the journal Radiology.
Growing awareness of risks from dental X-rays prompted the U.S. Food and Drug Administration (FDA) in 2009 to call on dentists to reduce radiation by switching to faster-speed types of X-ray film that require less radiation.
The fastest F-speed film typically requires 60 percent less radiation than slower D-speed film, which was used by 70 percent of U.S. dentists.
The FDA went so far as to advise patients to pressure dentists about the issue: “Ask your dentist or dental technician if they use the faster (E or F) speed film and tell them the reasons for your inquiry.”
The American Dental Association also recommends that dentists use F-speed film or digital imaging (which it says reduces radiation exposure by another 40 to 60 percent).
Canadian bodies have yet to follow suit. Health Canada’s latest guidelines for dental X-ray machines date back to 2000 and don’t explicitly call on dentists to switch to F-speed film or digital imaging.
Health Canada says only: “The fastest film or film-screen combination consistent with the requirements of the examination should be used.” The guidelines do, however, say that any amount of radiation increases cancer risks. “It is generally accepted that there is no safe level of radiation dose and that no matter how low a dose is used, there is a mathematical probability of an effect.”
The guidelines don’t mention CT scans.
The Canadian Dental Association also doesn’t explicitly ask dentists to switch to faster-speed or digital equipment and doesn’t discuss CT machines.
Its guidelines, which date to 2005, say: “Operators should select films of a speed and quality that will permit the production of radiographs of an acceptable diagnostic quality with minimum exposure of the patient to radiation.”
At the provincial government’s B.C. Centre for Disease Control (BCCDC), answers were hard to come by. Francine Anselmo, head of the centre’s medical X-ray program, at first asked for questions to be sent by email. After being informed that the Straight doesn’t conduct email interviews, Anselmo said she didn’t know what percentage of B.C. dentists use D-speed film.
When asked why her centre or Health Canada haven’t advised dentists to switch to faster film, as the U.S. FDA did in 2009, Anselmo said: “I have no idea.” Asked if she was familiar with studies linking dental X-rays to cancer, she said, “No, no, not at all.” And she replied, “Probably you’re talking to the wrong person,” when queried on whether or not her office has any concerns about radiation from dental X-rays.
Anselmo referred further questions to her supervisor at the BCCDC, Abderrachid Zitouni, the provincial radiation specialist.
The Straight left a phone message for Zitouni, but it was Anselmo who returned the call, asking again for questions to be emailed. Finally, another BCCDC employee, Karen Glassford, called to refer us to the centre’s media-relations person, Alex Dabrowski.
Dabrowski, in turn, referred the Straight to WorkSafeBC, the province’s workplace-safety agency, and the B.C. Dental Association.
At WorkSafeBC, spokeswoman Megan Johnston said her agency doesn’t deal with patient radiation safety: “Our mandate is only worker safety, so we wouldn’t be able to address questions about patient safety and exposure.”
Bruce Ward, spokesman and a past president of the B.C. Dental Association, said his group has no position on whether dentists should switch to higher-speed film or digital X-rays. He was skeptical when asked if Health Canada or dental associations should call on dentists to make the switch.
“I can’t say yes or no. If there was a health concern that came out, I would consider doing that. But if they [dentists] have something that works, then I don’t think there is a need to change when new technology comes along,” he said.
Ward acknowledged, however, that patients have lots of concerns about X-ray radiation. “It’s definitely huge. In my office, it’s a conversation that happens [with a patient] at least once a day,” he said on the phone from his home in Vancouver.
Ward said he himself switched from D-speed film to digital in his dental practice in North Vancouver seven years ago. “You want to be able to reassure people they are getting as little radiation as possible. Nobody likes to get X-rays.”
Ward said a common patient complaint is that some dentists do routine screening X-rays regardless of whether a patient has symptoms of a problem. He said routine X-rays are inappropriate and “certainly not a policy that’s supported by anyone, anywhere. If patients feel they are having X-rays done routinely, they should have a conversation with their dentist.”
Gina Ball, president of the B.C. Society of Orthodontists, said in an email that she was on vacation and also referred the Straight to the B.C. Dental Association.
At the Brain Tumour Foundation of Canada, spokeswoman Megan Winkler said research is virtually nonexistent on meningioma and its causes. It’s not even clear how many people get it, much less how to prevent it.
“It’s beyond frustrating. We need more research. If rates are going up, we need to know that so we are catching it sooner,” Winkler said on the phone from her office in London, Ontario.
Most provinces, including B.C., don’t compile standardized data on meningioma, she said.
At Thyroid Cancer Canada, president Rita Banach is concerned about exploding thyroid-cancer rates in Canada, which she thinks may be linked with increasing radiation exposure. Thyroid cancer is the fastest-growing type of cancer in Canada, with rates rising seven percent each year between 2002 and 2007, according to Statistics Canada.
“That may indicate we’re getting more radiation exposure in the environment from medical sources, Wi-Fi, cellphones,” Banach said on the phone from her home in Toronto.
“We should not be having CT scans unless it is absolutely indicated.”
Banach is a thyroid-cancer survivor herself. She had her thyroid gland and 11 lymph nodes removed in 1999. To kill any remaining cancer cells, she was given radioactive iodine, which damaged her salivary glands and left her with dry-mouth syndrome and a chronically dry throat. She now takes thyroid hormone every day.
“The basic question of what causes thyroid cancer doesn’t seem to be a priority, except to patients. The research is often driven by creating a drug, not on prevention. There’s no money to be made from prevention,” she said.
Back in Kelowna, Stanway spends her time in her apartment taking in the view of beautiful Dilworth Mountain and practising her new hobby: quilting for her son and daughter and five grandchildren. Her latest project was a quilted bedspread.
She still needs a CT scan or MRI every two years to see if the meningiomas have become cancerous. She tries not to worry about it—or about the fact that she is exposing herself to still more radiation.
When the headaches get really bad, she tries stretching. Through it all, she somehow manages to stay cheerful. “I am a gregarious, happy individual,” she says on her Google profile. “I have the love of music throughout me…I love to try new things.”
Her advice to others: “I would keep your dental X-rays to a minimum.”