Rowell N P, Flower M A, Cronin B, McCready V R
Department of Radiotherapy, Royal Marsden Hospital, Sutton, Surrey, UK.
Eur J Nucl Med. 1993 Jul;20(7):591-9. doi: 10.1007/BF00176553.
A single-photon emission tomography (SPET) technique for the absolute measurement of tumour perfusion is described. Phantom studies have shown that source-background ratios are dependent upon source size and radial position within the phantom. A means of correcting source-background count ratios for these variables has been developed and used to correct tumour-lung ratios obtained in 28 patients with bronchial carcinomas who underwent technetium-99m hexamethylpropyleneamine oxime (99mTc-HMPAO) SPET. On SPET images, the normal lung appears as a relatively homogeneous background. The relationship between 99mTc background concentration (kBq/ml) and counts/pixel was determined from phantom studies and the tumour 99mTc concentration from the background 99mTc concentration and corrected tumour-lung ratio. The total activity of the lipophilic 99mTc-HMPAO species injected was measured. The activity reaching the systemic circulation (Asys) was obtained by subtracting the activity trapped in the pulmonary circulation (obtained from background 99mTc concentration and lung volume). Tumour blood flow may then be calculated from fraction of Asys contained in the tumour provided cardiac output and extraction fraction are known. Blood flow through the central region of tumours ranged from zero to 59.0 (mean 14.1) ml min-1 100 g-1 and through the whole tumour from 0.6 to 68.0 (mean 20.6) ml min-1 100 g-1.
本文描述了一种用于绝对测量肿瘤灌注的单光子发射断层扫描（SPET）技术。模型研究表明，源-本底比取决于模型内的源大小和径向位置。已开发出一种针对这些变量校正源-本底计数比的方法，并用于校正28例接受锝-99m六甲基丙烯胺肟（99mTc-HMPAO）SPET检查的支气管癌患者所获得的肿瘤-肺计数比。在SPET图像上，正常肺表现为相对均匀的背景。通过模型研究确定了99mTc本底浓度（kBq/ml）与计数/像素之间的关系，并根据本底99mTc浓度和校正后的肿瘤-肺比确定肿瘤99mTc浓度。测量了注射的亲脂性99mTc-HMPAO物质的总活度。通过减去肺循环中滞留的活度（由本底99mTc浓度和肺体积获得）来获得到达体循环的活度（Asys）。如果已知心输出量和提取分数，则可根据肿瘤中所含Asys的分数计算肿瘤血流量。流经肿瘤中心区域的血流量范围为0至59.0（平均14.1）ml·min-1·100g-1，流经整个肿瘤的血流量范围为0.6至68.0（平均20.6）ml·min-1·100g-1。
