Question

What are the characteristics of In-111 and when is it used for gastric emptying?

Answer 1

Indium-111 (¹¹¹In) is a radioactive isotope of Indium (In). ¹¹¹In has a half-life (t_1/2) of 2.81 days decaying by electron capture to ¹¹¹Cd, which is stable (non-radioactive). During its radioactive decay, it emits low energy gamma photons which can be imaged using planar or SPECT gamma cameras. So, It is commonly used in Nuclear Medicine Diagnostic Imaging by radio-labeling targeted molecules or cells.

Due to the limited availability of In-123 and its relatively short half-life, the majority of the early imaging studies were completed with
In-131.Along with improvements in the antibodies available for clinical investigations came the need for better radionuclides
for diagnostic imaging. Use of In-111 for radioimmunodetection is advantageous because of the excellent imaging characteristics of the In-111, moderate radiation dose, ease of labeling, and appropriate half-life.

In Gastric emptying, To accurately quantify solid emptying, the radiotracer must be tightly bound to the solid meal. Generally, radiolabel egg albumen with sulfur colloid is used in most nuclear medicine laboratories. However, Measuring simultaneous solid and liquid emptying is feasible using a dual isotope study by radiolabeling a liquid phase with In-111 DTPA (Indium-111 diethylenetriamine pentaacetic acid). A clear liquid study may be useful in a patient intolerant of solids but able to retain liquids.To evaluate liquid emptying, water is labeled with In-111 DTPA.