Final answer:
CT scans use X-rays to create detailed cross-sectional images of the body. MRIs use magnetic fields for soft tissue imaging, PET scans visualize body functions with radioactive substances, and ultrasound employs sound waves, being the least invasive and radiation-free method.
Step-by-step explanation:
Comparison of Medical Imaging Techniques
Medical imaging technologies such as CT scans, MRIs, PET scans, and ultrasonography provide different types of information about the body's internal structures and functions. Computed Tomography (CT) or computed axial tomography (CAT) is a technique where multiple X-ray measurements from different angles are processed by computers to produce cross-sectional images of the body. A CT scan involves the patient lying on a platform while an X-ray tube rotates around them, capturing detailed images of internal bodies in slices. A computer then reassembles these images into a two-dimensional view of the scanned area.
The CT scan's advantage is its ability to provide detailed pictures of bones, organs, and other tissues. Interestingly, CT scans and other techniques like SPECT use ionizing radiation, which could be harmful in excessive amounts, whereas MRI (Magnetic Resonance Imaging) and ultrasound do not. MRIs employ strong magnetic fields and radio waves to produce highly detailed images of the body's soft tissues. PET scans utilize radioactive substances to image bodily functions, such as blood flow or metabolic processes, which are particularly useful in detecting cancer. Ultrasounds, often used in pregnancy, employ sound waves to image the body and are the least invasive with no radiation exposure.