Cancer Detection: Which Scans Work Best?

Cancer is the abnormal growth of cells in an organ or structure in the body. As the abnormal cells grow, they can take over the organ, preventing it from functioning properly. The abnormal cells can also spread to other parts of your body and infect other organs – a process called metastasis. Because cancer destroys organs, it is considered a life-threatening condition and early detection is crucial for treatment to stop the growth and reverse the illness.

Thanks to advancements in the technology of body imaging scans, it is now possible to detect cancer in the very early stages, in order to effectively treat the disease before it has a chance to make you very ill. However, with so many diagnostic scans available, how can you tell which one is best for detecting cancer?

Common Body Scans for Detecting Cancer

Body scans fall into five categories: nuclear medicine, x-rays, magnetic resonance imaging (MRI), endoscopy and ultrasound.

Nuclear Medicine

Nuclear medicine uses radioactive isotopes to detect and diagnose cancers. Nuclear medicine lets a doctor observe the organs in action and helps them determine the location of the disease. Depending on the organ in question, you might ingest a radioactive substance (also known as a radionuclide or tracer), or have it injected into your veins for the scan. Cameras in the nuclear scanning machine will trace how much of the tracer is absorbed by certain areas of the body--more absorption can indicate the presence of cancer (or a tumor) and the extent of it. Examples of common nuclear scans include the PET scan or the combined PET/CT scan.


X-rays use electromagnetic energy to detect and diagnose problems in your body. Examples of x-ray technology include the standard x-ray, computed tomography (CT scans), and mammograms. A standard x-ray works best on bone and other dense tissues, and is good for detecting bone cancers or tumors in the lungs. Advanced x-ray machines, like the CT scan or mammogram are good for detecting cancers in softer tissues, like the breasts.

Magnetic Resonance Imaging (MRI)

The MRI uses magnets to detect and diagnose cancers. MRI scans can work on soft or dense tissue and are especially useful in viewing the spinal cord and brain.


Endoscopy involves a procedure wherein a tiny camera is inserted in your body (usually while you are under anesthesia) to detect and diagnose cancers and other problems. Endoscopy is generally used on organs and systems that can be accessed through a body opening like your colon or stomach. Endoscopy lets your doctor observe your organs in action, and he can also see clearly see the size, shape, and color of any growths, tumors or lesions – all of which can help him detect cancer.


Ultrasound uses sound waves to detect and diagnose cancers. Ultrasounds work best on soft tissues, like the breasts, testicles and abdomen. Ultrasound is one of the few diagnostic scans that does not use radiation, so it is safe for use on pregnant women and children, and others concerned about limiting radiation exposure.

Deciding on the Right Scan

There really is no one scan that is best for detecting all cancers. This is because not all cancers are the same, and because some scans work better on certain parts of the body than others.

For example, an x-ray is great for detecting bone and lung cancers, but it won’t work to detect breast or prostate cancer. Conversely, a mammogram or ultrasound can detect breast and prostate tumors, but it could completely miss a bone tumor.

Additionally, a diagnostic scan only tells part of the story. To get a full diagnosis, your physician also needs to draw blood or collect tissue for lab tests, and even consult with a specialist. When it comes to choosing a scan, your doctor will be able to use his or her skill and expertise to determine which imaging procedure is best for you.

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