Thorium (232Th) is a naturally radioactive element. Thorium is the parent nuclide of one radioactive series, and specific thorium nuclides are decay products of three radionuclide series.

See also Thorotrast.

Thorotrast is an obsolete contrast medium containing a colloidal suspension of thorium dioxide. Contrast agents based on thorium have been abandoned since they turned out to be carcinogenic.

Tomocat® is a concentrated strawberry flavored barium sulfate suspension. Tomocat® can be used as an oral or rectal (colon) contrast medium for computed tomography of the gastrointestinal tract. The quantity and the barium sulfate concentration will depend upon examination, used technique, clinical needs and patient size.

Tomography is imaging by sections or sectioning to obtain images of slices through objects like the human body. Tomography is derived from the Greek words 'to cut or section' (tomos) and 'to write' (graphein). A device used in tomography is called a tomograph, while the image produced is a tomogram.
The first medical applications utilized x-rays for images of tissues based on their x-ray attenuation coefficient. The mathematical basis for tomographic imaging was laid down by Johann Radon. This type of imaging is used in different medical applications as for example computed tomography, ultrasound imaging, positron emission tomography and magnetic resonance imaging (MRI) also called magnetic resonance tomography (MRT).
Conventional x-ray tomographic techniques show organ structures lying in a predetermined plane (the focal plane), while blurring the tissue structures in planes above and below by linear or complex geometrical motion of the x-ray tube and film cassette.
Basically, computed tomography is the reconstruction of an image from its projections. In the strict sense of the word, a projection at a given angle is the integral of the image in the direction specified by that angle. The CT images (slices) are created in the axial plane, while coronal and sagittal images can be rendered by computer reconstruction.

See also Zonography, Computed or Computerized Axial Tomography, Resolution Element, Radiographic Noise, Intravenous Pyelogram.

Also called axial, transverse, horizontal. A plane perpendicular (rotated 90°) to the long axis of the human body.