The Role of X-rays in Cancer Screening & Early Detection

Feb 12, 2024 7:15:00 AM Posted by Iowa Radiology

Iowa Radiology X-ray

Cancer screening helps save lives by finding developing cancers early, before they begin to cause symptoms. Generally speaking, the earlier a cancer is detected, the more successfully it can be treated. With early-stage cancers, treatments may also be far less invasive and easier for patients to tolerate. X-ray exams play a critical role in screening for breast, lung, and colon cancer.


Leading professional organizations, including the American College of Radiology, the National Comprehensive Cancer Network, and the Society of Breast Imaging, recommend that women start undergoing annual mammography screening beginning at age 40. A systematic review published in 2015 found that for women at average risk, mammography screening reduced the chances of dying from breast cancer by 20%. Those at higher risk should consult their doctors, who may recommend beginning screening earlier. (You can get a quick estimate of your lifetime breast cancer risk here).

While all mammograms use X-rays, they don’t all work the same. Traditional mammography provides the familiar 2-D X-ray images, while modern 3-D digital mammography creates 3-D images that radiologists can examine in much greater detail, zooming in on minute areas of interest. Additionally, the 3-D images can be turned, allowing doctors to see what lies behind structures that would normally obstruct their view. While 2-D mammography takes two sets of images of each breast, 3-D mammograms create multiple images from different angles as the machine moves in an arc around the breast.

3-D mammography has the potential to identify more cancers than traditional 2-D screening. A study published in 2014 that evaluated nearly 455,000 mammograms found that 3-D mammography increased the detection of invasive cancers by 41%.[1] Additionally, a study published in JAMA in 2016 determined 3-D mammography detected more cancers and returned fewer false positives—and that these gains were greatest among women with dense breasts, a normal condition that can make breast cancer harder to identify and increase a patient’s risk.[2]


Low-Dose CT Lung Screening

Much like 3-D mammography, computed tomography (CT) uses X-rays to create 3-D images of the body. Low-dose CT (LDCT) lung screening uses this technology to identify early signs of lung cancer in at-risk patients. The US Preventive Services Task Force, which influences which procedures insurers must cover, currently recommends annual LDCT screening for patients who meet these criteria:

  • Current smoker or quit within the past fifteen years
  • A smoking history of at least 20 pack-years
  • Between ages 50 and 80

A pack-year is the equivalent of a pack of cigarettes a day for one year. This might be, for example, a pack a day for 20 years, two packs a day for 10 years, or ½ pack a day for 40 years. Because smoking is not the only risk factor for developing lung cancer, talk to your doctor if you have other types of risks, such as exposure to asbestos or other lung carcinogens. Because of its potential to flag features that are not, in fact, cancers, LDCT lung screening is not recommended for patients at average risk.


Virtual Colonoscopy

CT technology is also used for colon cancer screening, providing a less invasive alternative to traditional colonoscopy screening. Colorectal cancer is the third and fourth leading cause of cancer death in the U.S. for men and women, respectively. However, more than 90% of those whose cancers are caught at the earliest stages survive at least five years after their diagnosis.[3] CT colonography, commonly known as virtual colonoscopy, allows radiologists to examine the colon from the outside, eliminating the need to insert a camera into the body. As a result, the risk of bowel perforation is reduced, and there is no need for sedation during the procedure.

In a virtual colonoscopy, a small, flexible tube is inserted into the rectum to inflate the colon with carbon dioxide. This allows the CT device to image the bowel’s interior so radiologists can identify any abnormalities. Since no sedation is required and the procedure is minimally invasive, patients can resume their normal activities immediately following the exam. The carbon dioxide will be quickly absorbed by the body but can leave patients feeling gassy in the meantime. If polyps are identified during CT colonography, then a follow-up colonoscopy will be scheduled to remove them. Otherwise, the patient can simply repeat the screening in five years.


Cancer Screening at Iowa Radiology

Iowa Radiology is dedicated to excellent patient care, which includes investing in cutting-edge technology. We offer CT colonography, LDCT lung screening, and 3-D mammography as well as both abbreviated and high-risk MRI for breast cancer screening. To learn more about the latest in cancer screening technology and other health topics, subscribe to our blog.



Friedewald, Rafferty, et al. Breast Cancer Screening Using Tomosynthesis in Combination with Digital Mammography. JAMA vol. 311, no. 24, 2014, pp. 2499–2507.

Rafferty, Durand, Conant. Breast Cancer Screening Using Tomosynthesis and Digital Mammography in Dense and Nondense Breasts. JAMA 2016;315(16):1784–1786.

American Cancer Society. Key Statistics for Colorectal Cancer. Revised January 17, 2024. Accessed January 18, 2024.

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