Nuclear Medicine

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Browsing Nuclear Medicine by Author "Bester, Maria J."

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    n Vergelyking tussen gallium-67-sitraat en tegnesium-99m-HMPAO gemerkte leukosiete vir die opspoor van inflammatoriese letsels
    (Stellenbosch : Stellenbosch University, 1993) Bester, Maria J.; Stellenbosch University. Faculty of Medicine and Health Sciences. Dept. of Nuclear Medicine.
    ENGLISH ABSTRACT: Prior to the availability of radiolabelled leukocytes, Ga-67 citrate was the radiopharmaceutical of choice in the detection of inflammatory lesions. Use of gallium-67 however, entails several disadvantages. The aim of this prospective study was to further elucidate the clinical value of Tc-99m HMPAO labelled leukocytes in the detection of inflammatory lesions and to compare it with that of gallium. Leukocyte imaging studies were performed in 90 patients over a 3 year period. A broad spectrum of infective and inflammatory diseases was investigated. In 50 patients in this study, imaging was also done after administration of Ga-67. The results were compared to th05e of bacterial cultures, histology, other imaging modalities as well as clinical outcome. Because we were interested in verifying the effects of cell isolation and labelling on the ultrastructural and functional cells, electronmicroscopy and investigations of leucocyte function such as chemotaxis, superoxide production and chemiluminescense were performed. On electronmicroscopy the cells showed no marked ultrastructural changes after cell labelling although the function tests showed a marked deficit in functional integrity. In spite of this the labelled leukocytes showed a normal distribution in vivo. The results of the leukocyte studies (sensitivity 97,8%, Specificity 95,8%.) were superior to those of gallium (sensitivity 73,9%, specificity 77,8%.) Early (30-60 min) imaging after leukocyte administration showed no intestinal excretion of activity, thus enabling one to distinguish between lesions and normal excretion. In no instance did oallium-67 indicate inflammatory lesions that were not also apparent on the white cell study. Specifically in abdominal sepsis, inflammatory bowel disease, acute osteitis and inflammatory and infective conditions of the kidneys, Tc-99m HMPAO labelled leukocytes showed a better sensitivity and specificity than Ga-67 citrate in correctly identifying these conditions. This study indicates that Tc-99m HMPAO leukocyte scintigraphy is of great value in the diagnosis of several inflammatory diseases. Tc-99m is readily available and the image quality, is superior to that obtained with Ga-67 ci trate. Results are available more rapidly and the radiation dose is lower. Although leukocyte labelling is a time consuming and labour intensive procedure, imaging is usually optimal 30-60 minutes after administratlon compared to 6-72 hours for gallium-b7. The results of our comparative study showed a higher sensitivity and specificity for Tc-99m labelled leukocytes compared to gallium-67 in the detection of inflammatory lesions.