If you’re thinking about working in the field of medical imaging, it’s important to understand the differences between the different kinds of medical imaging procedures and radiology technologies. The field of medical imaging contains a variety of different procedures and specialties, and each requires special training and education. You can’t assume you can just jump from one specialty to another without preparation. That said, since many medical imaging procedures do have a lot in common, you’ll frequently find technicians that specialize in more than one procedure. Health care professionals who work in the field of medical imaging are known as radiologic technicians or technologists. However, those are just blanket terms; most radiologic technicians have additional titles that specifically describe the medical imaging they are involved with.
The most well-known form of medical imaging is radiography, more commonly known as x-rays. Health care professionals who take x-rays are known as x-ray technicians or radiographers. X-ray technicians operate an x-ray machine that aims a small amount of radiation at a particular part of the body. How easily that radiation passes through the body part determines what the x-ray image will look like. For example, x-rays cannot easily pass through bones since the bones absorb the x-rays, which is why the bones appear white on x-ray images. X-rays can pass through soft tissues much more easily, which is why other areas appear darker on x-ray images.
In addition to doing standard x-rays, x-ray technicians may specialize in something called bone densitometry. A bone densitometry technician doesn’t just look at the structure of a bone; they look for the bone mineral density as well. This density can be used to estimate bone loss and risk of fractures. Another medical imaging procedure that uses x-rays is mammography, a procedure specifically designed to image breasts. Mammography usually calls for lower energy x-rays than bone densitometry does.
A very different type of medical imaging that also uses x-rays is computed tomography (CT). CT may use x-rays, but the images produced by CT are not the standard 2-D ones you would expect. During a CT scan, the x-ray machine rotates around the patient, producing multiple 2-D images that a computer combines into a layered 3-D image. Doctors can actually look inside organs thanks to the CT images created by computed tomography technicians.
Magnetic resonance imaging (MRI) creates images through an entirely different process. Instead of x-rays, MRIs use magnets. When a patient undergoes an MRI scan, they are exposed to a magnetic field. The MRI technician turns on a radiofrequency pulse, which causes the atoms in the patient’s body to go out of alignment. After the MRI technician turns off the pulse, the atoms go back to normal. A computer is used to track the movement of the atoms, which results in an MRI image. Whereas x-ray images don’t show soft tissues very well, soft tissues show up perfectly on MRI images, which makes MRI scans ideal for imaging areas of the body such as the brain, vascular system and joints.
Ultrasound, also known as sonography, is another form of medical imaging. As the name suggests, ultrasound uses sound waves to create images. An ultrasound technician, also known as a sonographer, uses a transducer, a special device that both emits and receives high-frequency sound waves. This transducer sends sound waves through the body. The sound waves bounce off the organs and tissues in the body and are received by the transducer. These echoes are converted into images by a computer. Like MRIs, ultrasounds are great for imaging soft tissues. Most people are familiar with ultrasound since it is common for pregnant women to get ultrasounds to determine the well-being and number of the fetuses they are carrying.
Another form of medical imaging is nuclear medicine. Nuclear medicine technicians administer radiopharmaceuticals, which are radioactive materials, to patients. These radiopharmaceuticals are attracted to particular areas of the body, and they emit radiation that can be tracked with a special camera. Nuclear medicine is an especially valuable form of medical imaging because it doesn’t just show the structure of an organ; it also shows how well the organ is functioning. For example, a doctor expects to find a certain concentration of radiation in a particular organ. If the resulting images show higher or lower concentrations of radiation, then the doctor knows that the organ is not functioning correctly. Nuclear medicine is commonly used to image organs such as the brain, lungs, heart, liver, gallbladder, thyroid and bones.