Imaging of abdominal inflammation using other radioisotope techniques.

99mTc-HMPAO-labelled white cell scanning is compared with other radionuclide techniques in this contribution. The sensitivity and specificity using both 111In and 99mTc-HMPAO-labelled leucocytes are comparably high. Both imaging methods are therefore suitable for imaging inflammation. However, images are available more quickly using 99mTc-HMPAO; their quality is superior and the radiation dose is lower. 111In is beneficial for chronic infections. 67Ga citrate is less specific for inflammation, since it also localizes in tumours, but it is useful in chronic infection. 99mTc nanocolloid has not been found suitable for imaging abdominal inflammation, but more so for bone and joint diseases. Comparisons of 99mTc-HMPAO leucocytes with 123I-labelled monoclonal antibodies show poorer results using the monoclonal antibody because of non-specific binding to plasma proteins. Visualization of lesions is generally poorer using 99mTC-HIG than 99mTc-HMPAO leucocytes and is less sensitive and specific. Few reports using 99mTc-labelled monoclonal antibodies are available. Early results are promising and more specific antibodies may be available in the future. Synthetic chemotactic peptides offer a novel approach to the detection of infection. However, at present the recommended method for imaging acute abdominal inflammation is 99mTc-HMPAO leucocytes.