Overview

In modern medicine, medical imaging has undergone major advancements. Today, this ability to achieve information about the human body has many useful clinical applications. Over the years, different sorts of medical imaging have been developed, each with their own advantages and disadvantages.

X-ray based methods of medical imaging include conventional X-ray, computed tomography (CT) and mammography. To enhance the X-ray image, contrast agents can be used for example for angiography examinations.

Molecular imaging is used in nuclear medicine and uses a variety of methods to visualize biological processes taking place in the cells of organisms. Small amounts of radioactive markers, called radiopharmaceuticals, are used for molecular imaging.

Other types of medical imaging are magnetic resonance imaging (MRI) and ultrasound imaging. Unlike conventional X-ray, CT and Molecular Imaging, MRI and ultrasound operate without ionizing radiation. MRI uses strong magnetic fields, which produce no known irreversible biological effects in humans.

Diagnostic ultrasound systems use high-frequency sound waves to produce images of soft tissue and internal body organs.

  • Fig. 1: The basic setup for X-ray imaging. The collimator restricts the beam of X-rays so as to irradiate only the region of interest. The antiscatter grid increases tissue contrast by reducing the number of detected X-rays that have been scattered by tissue.

    Imaging using X-rays

    X-ray imaging uses an X-ray beam that is projected on the body. When passing through the body, parts of the x-ray beam are absorbed. On the opposite side of the body, the X-rays are detected, resulting in an image.

  • Molecular Imaging

    Molecular imaging provides detailed information of the biological processes taking place in the body at cellular and molecular levels and can indicate disease in its earliest stages.

  • Fig. 1: Ultrassom pré-natal 3D mostrando a cabeça, bracos e mãos do bebê.

    Other Types of Medical Imaging

    Some types of medical imaging work without using ionizing radiation, for example magnetic resonance imaging (MRI) and ultrasound imaging, and have specific uses in the diagnosis of disease.