Davidson B R, Waddington W A, Short M D, Boulos P B
Department of Surgery, University College, Middlesex School of Medicine, London, UK.
Br J Surg. 1991 Jun;78(6):664-70. doi: 10.1002/bjs.1800780610.
Radiation detectors may allow the intraoperative localization of small cancer deposits following administration of radiolabelled tumour-associated antibodies. This technique was evaluated in 16 patients with colorectal tumours (14 cancers, one adenoma, one lipoma) with the 111In-labelled monoclonal antibody (MAb) ICR2 which recognizes the tumour-associated epithelial membrane antigen (EMA). At operation counting was carried out (3 x 20 s per site) using a hand-held radiation probe over the primary lesions and any palpable lymph nodes in the mesocolon. The tumour to normal colon (T/NC) ratio of counts recorded at operation was more than 1.5:1 in eight of the 14 patients with cancer (mean(s.d.), 1.54(0.41):1) and 0.91:1 and 1.06:1 respectively in the two patients with benign tumours. Node to normal colon ratios were higher in lymph nodes containing metastases. The uptake of radiolabelled antibody (T/NC ratio) was higher in EMA-expressing cancers than in those not expressing the target antigen (mean(s.d.), 2.45(0.65):1 versus 1.40(0.20):1, P = 0.019). An abdominal tumour model was also developed. Radioactively filled containers of 0.5-10 ml representing tumour deposits were suspended in a tank of 111In solution representing the background activity found in normal tissues. The ratio of radioactivity in the 'tumour' to that of background varied from 2:1 to 8:1. The 'tumour' was considered to be detectable if the mean counts recorded over the 'tumour' exceeded the mean of counts recorded over background by three standard deviations. At a ratio of 2:1 only 'tumours' greater than 5 ml could be detected with a sodium iodide probe and those over 10 ml could be detected with a cadmium telluride (CdTe) probe. At a ratio of 8:1, 'tumours' of 0.5 ml could be detected with either probe. At all ratios and counting periods the NaI probe was more sensitive than the CdTe.
在给予放射性标记的肿瘤相关抗体后，辐射探测器可实现术中对小癌灶的定位。本技术在16例结直肠肿瘤患者（14例癌症、1例腺瘤、1例脂肪瘤）中进行了评估，使用了识别肿瘤相关上皮膜抗原（EMA）的铟-111标记单克隆抗体（MAb）ICR2。手术时，使用手持辐射探测器在原发灶及结肠系膜中任何可触及的淋巴结处进行计数（每个部位计数3次，每次20秒）。14例癌症患者中有8例手术时记录的肿瘤与正常结肠（T/NC）计数比值大于1.5:1（均值（标准差），1.54(0.41):1），2例良性肿瘤患者的该比值分别为0.91:1和1.06:1。有转移的淋巴结与正常结肠的比值更高。表达EMA的癌症中放射性标记抗体的摄取（T/NC比值）高于不表达靶抗原的癌症（均值（标准差），2.45(0.65):1对1.40(0.20):1，P = 0.019）。还建立了一个腹部肿瘤模型。将代表肿瘤灶的0.5 - 10毫升放射性填充容器悬浮于代表正常组织中背景活性的铟-111溶液槽中。“肿瘤”中的放射性与背景放射性的比值在2:1至8:1之间变化。如果在“肿瘤”上记录的平均计数超过背景记录计数的平均值3个标准差，则认为“肿瘤”可被检测到。在2:1的比值下，使用碘化钠探测器仅能检测到大于5毫升的“肿瘤”，使用碲化镉（CdTe）探测器能检测到大于10毫升的“肿瘤”。在8:1的比值下，两种探测器均可检测到0.5毫升的“肿瘤”。在所有比值和计数时间段，碘化钠探测器比碲化镉探测器更敏感。
