ack pain can be excruciating. So it seems that getting an X-ray, CT scan, or MRI to find the cause would be a good idea. But that’s usually not the case, at least at first. Here’s why.

They don’t help you get better faster.

Most people with lower-back pain feel better in about a month whether they get an imaging test or not. In fact, those tests can lead to additional procedures that complicate recovery. For exam­ple, a study that looked at 1,800 people with back pain found that those who had imaging tests soon after reporting the problem fared no better and sometimes did worse than people who took simple steps like applying heat, staying active, and taking an OTC pain reliever. Another study found that back-pain sufferers who had an MRI in the first month were eight times more likely to have surgery, and had a five-fold increase in medical expenses—but didn’t recover faster.

They can pose risks.

X-rays and CT scans expose you to radiation, which can increase cancer risk. One study projected 1,200 new cancers based on the 2.2 million CT scans of the lower back performed in the U.S. in 2007. While back X-rays deliver less radiation, they’re still 75 times stronger than a chest X-ray. That’s especially worrisome to men and women of childbearing age, because X-rays and CT scans of the lower back can expose testicles and ovaries to radiation. And the tests often reveal spinal abnormalities that could be completely unrelated to the pain. For example, one study found that 90 percent of older peo­ple who reported no back pain still had spinal abnormalities that showed up on MRIs. Those findings can cause needless worry and lead to unnecessary follow-up tests and procedures such as injections or sometimes even surgery.

They’re often a waste of money.

An X-ray of the lower back ranges from about $200 to $290, an MRI from $880 to $1,230, and a CT scan from $1,080 to $1,520, according to HealthCareBlueBook.com. Imaging also accounts for a big chunk of the billions Amer­icans spend on lower-back pain each year, not only for the tests themselves, but also the unnecessary interventions they trigger.

When do imaging tests make sense?

It can be a good idea to get an imaging test right away if you have signs of severe or worsening nerve damage, or a serious underlying problem such as cancer or a spinal infection. Red flags that can make such testing worthwhile include a history of cancer, unexplained weight loss, fever, recent infection, loss of bowel or bladder control, abnor­mal reflexes, or loss of muscle power or feeling in the legs. In other cases, you probably don’t need an imaging test for at least several weeks after the onset of your back pain, and only after you’ve tried the self-care measures described at right.

How should you treat lower-back pain?

Most people get over back pain in a few weeks, and these simple steps might help.

• Stay active. Resting in bed for more than a day or so can cause stiffness, weakness, depression, and slow recovery.

• Talk with your physiotherapist. If symptoms don’t improve after a few days, consider seeing a physiotherapist to make sure that you don’t have any red flag symptoms, which indicate a more serious underlying health prob­lem. Some simple education and management techniques can provide relief with acute conditions.

Consider the evidence in favour of supervised exercise, including yoga.  If you don’t feel better after four weeks or so, a physiotherapy program, with a postural exercise component, is worth considering. Pain that has lasted over 3 months is best treated with individualised exercise programs such as yoga therapy, which includes mindfulness and progressive muscle relaxation. More invasive choices, such as surgery, are considered a last resort, although many patients with chronic pain should never be operated on.