Medical Tests & Procedures Archive

Diagnostic technology makes it possible to detect many conditions. But is it safe to get lots of x-rays or CT scans?

When your doctor orders an occasional x-ray or computed tomography (CT) scan, you probably focus on the findings, not the amount of radiation you'll be exposed to. But if you need numerous tests, you may wonder if you're getting too much radiation exposure and how it might affect you. The concern about radiation exposure is an increased risk for developing cancer later in life. Ionizing radiation from tests such as x-rays or CT scans has the potential to damage tissue in the body, including cell DNA.

"As DNA is damaged, this causes mutations. Some of these are repaired by our cells, but others escape repair. In rare circumstances, these mutations may cause cells to divide rapidly without control," explains Dr. Mark Hammer, a radiologist with Harvard-affiliated Brigham and Women's Hospital. "If cancer were to develop, it could take 10 to 20 years for it to become apparent."

On call

Q. I am 74 years old and unsure whether I want to continue with PSA screening for prostate cancer. Before deciding, I wanted to better understand my options since I probably would not want surgery or radiation therapy if I do have prostate cancer. What is your approach?

A. No matter what your age, men should ask themselves these types of questions before having a blood test for PSA (prostate-specific antigen) to look for hidden prostate cancer.

Whether you've had a stent placed or may need one in the future, here's what you should know about these tiny devices

Close to a million heart stents to open blocked or narrowing arteries are implanted each year in the United States, and as you age, the odds rise that you'll end up on the list of recipients.

"Getting a stent can save your life during a heart attack, but what you do after the procedure can dictate your future heart health," says Dr. C. Michael Gibson, a cardiologist with Harvard-affiliated Beth Israel Deaconess Medical Center.

In the journals

Blood pressure readings are usually done on only one arm, but a new analysis makes the case for checking both arms, as the difference between them may suggest an elevated risk for heart disease. The findings were published in the February 2021 issue of Hypertension.

Researchers examined 24 studies that measured blood pressure in both arms in 53,827 adults without high blood pressure. They found that a difference of more than five points between the left and right arm systolic readings (the top number) was linked with a 9% higher risk for a first-time heart attack or stroke and a 6% increase in cardiovascular death within 10 years. The greater the difference between the two readings, the higher the risk.

Your genes affect how your body responds to many drugs. But pharmacogenomic testing still isn't ready for routine use.

Most genetic tests focus on your odds of developing certain diseases or health conditions. But some — known as pharmacogenomic (or pharmacogenetic) tests — can reveal how your body may respond and react to different medications. To date, researchers have identified more than 400 genetic variations known to affect the metabolism of numerous drugs, including some that help lower cholesterol or prevent blood clots (see "Pharmacogenomics of common heart drugs").

In theory, knowing how people metabolize specific drugs could help doctors choose the safest, most effective treatment for their patients. But in practice, it's not that straightforward, says Dr. Jason Vassy, assistant professor of medicine at Harvard Medical School and a primary care physician at the VA Boston Healthcare System.

In the last decade, overall rates of colorectal cancer have been falling among the general population in the US. However, African Americans are more likely to develop colorectal cancer at younger ages, and to die from it. The reasons for this disparity are unclear, but they are rooted in socioeconomic and racial inequities.

Recent advances can help men with a worrisome PSA result avoid immediate biopsy.

Prostate-specific antigen (PSA) blood testing receives high marks as an effective way to monitor disease activity in men diagnosed with prostate cancer. Yet, as a screening tool for prostate cancer, PSA testing is problematic.

PSA naturally tends to increase as men get older, but levels that get too high may suggest prostate cancer. A PSA level of less than 4 nanograms per milliliter (ng/mL) is often reassuring, unless there has been a sudden jump from a much lower number. Many doctors consider a total PSA level higher than 10 ng/mL as the threshold for getting a biopsy to check for cancer.

Ask the doctor

Q. My aunt was having heart palpitations and recently found out that she has bigeminy. According to her doctor, it's not serious. But what exactly is this condition?

A. Bigeminy refers to a heartbeat marked by two beats close together with a pause following each pair of beats. The term comes from the Latin bigeminus, meaning double or paired (bi means two, geminus means twin).

There are wrong ways and right ways to measure your blood pressure. Watch Harvard Heart Letter Editor Patrick Skerrett demonstrate both.

Buy a monitor that meets the test

There are dozens of home blood pressure monitors on the market. You can buy a good one at your local pharmacy or a big-box store for anywhere between $60 and $100.

Ask the doctor

Q. In last month's Heart Letter, you described some of the ways your heart rate reflects your health. But I've also heard about another measurement, called heart rate variability. Can you explain what that's all about?

A. Heart rate variability (HRV) is a sophisticated measurement of the variation in time between each heartbeat. We know that a heart rate that's too slow, too fast, or irregular can signal a problem, so it's only natural to think that a steady, regular pulse is a sign of a healthy heart. And you might also assume that having little or no difference in the time between each beat (that is, a low HRV) is best.