Final answer:
The contrast medium used for diagnosis of digestive tract disorders administered rectally via enema is barium sulfate. Not to be confused with radiopharmaceuticals, barium sulfate is insoluble and safe for X-ray imaging, used to diagnose conditions such as acid reflux, Crohn's disease, and ulcers.
Step-by-step explanation:
The contrast medium used in the diagnosis of digestive tract disorders, which is administered rectally via enema, is barium sulfate. Although it's important to be aware that soluble barium salts are toxic, barium sulfate stands out because it is exceptionally insoluble, making it non-toxic when used for medical imaging. This property prevents barium sulfate from being absorbed into body tissues, allowing it to safely provide a clear outline of the digestive organs during X-ray procedures. This contrasts with the use of radiopharmaceuticals, which involve radioactive substances that are often administered in small doses to image various organs but are not typically used in gastrointestinal imaging.
Barium sulfate is indicated for a variety of conditions such as acid reflux disease, Crohn's disease, and various types of ulcers. When evaluating the gastrointestinal tract, other techniques, like the ingestion of radioactive substances (like radioactive fatty acids and isotopes of iron and vitamin B12), are employed to assess absorption and function, but these are usually not administered by enema.