What Is an Ultrasound?
Ultrasound imaging uses high-frequency sound waves to create an picture of the prostate. Ultrasound imaging is sometimes called sonography and can be used to evaluate many parts of the body and internal organs.
How Does This Apply to Prostate Cancer?
Ultrasound is often used early on in the diagnosis of prostate cancer to determine if the prostate is enlarged or has an abnormal or asymmetrical shape. Ultrasound is also used very frequently during a prostate biopsy to guide the physician to biopsy exactly where needed.
How Does It Work?
In order to produce an image of the prostate, a thin ultrasound probe is inserted a short distance into the rectum. This probe is what emits the high-frequency sound waves and detects their return. These sound waves can then be detected and measured as they reflect off of various structures inside the body.
Different types of structures reflect (or “echo”) sound waves differently. These differences can be detected and an image produced showing where one type of structure stops and another starts. This allows for a detailed view of the area near the ultrasound probe.
That Sounds a Lot Like the Sonar That Ships Use. Is That Right?
Yes. The sonar used in ships to detect underwater objects such as fish or submarines is based on the very same principles as ultrasound imaging.
What Kind of Measurements Can an Ultrasound Make?
When sound waves echo off of an object, they change slightly. The ultrasound machine can interpret these very tiny changes in the character of the returning sound wave to make determinations about the object (such as the prostate) that it has hit.
Measurements can be made about the size and shape of the object, how far from the probe it is, and what its makeup is. For instance, ultrasound can determine whether an object is solid, full of liquid, or a little of both.
I’ve Heard That Ultrasound Is “Live.” Is That True?
Yes. Ultrasound, in a sense, is “live.” As the ultrasound is being performed, the image that is produced is in real-time. This means that procedures can be done while an ultrasound image is being produced. For instance, most prostate biopsies are done using “live” ultrasound imaging that allows the physician to know exactly where to perform the biopsy.