Hockaday David C, Shen Sui, Fiveash John, Raubitschek Andrew, Colcher David, Liu An, Alvarez Vern, Mamelak Adam N
Neurosurgery Section, Department of General and Oncological Surgery, City of Hope Cancer Center, Duarte, California 91010, USA.
J Nucl Med. 2005 Apr;46(4):580-6.
TM-601, a 36-amino-acid peptide, selectively binds to glioma cells but not normal brain parenchyma. A phase I/II clinical trial of intracavitary 131I-TM-601 in adult patients with recurrent high-grade glioma was performed to determine the biodistribution and toxicity of this potential therapy. We evaluated imaging and biodistribution data from this trial to assess whether 131I-TM-601 might be useful in determining tumor extent.
Adult patients with recurrent high-grade gliomas underwent tumor resection, implantation of an intracavitary reservoir, and a single-dose injection of 370 MBq (10 mCi) 131I-TM-601 (0.25-1.0 mg of 131I-TM-601) 2-4 wks after surgery. Total-body planar scans and whole-brain SPECT scans were obtained on days 0, 1, 2, 3, and 6-8 after injection. Postresection MR images were coregistered to the SPECT scans using image analysis software. Analysis of the rate of radioactive decay and biologic elimination from the body and at the cavity site was performed. T1-weighted with gadolinium contrast (T1-Wc), T2-weighted (T2), and SPECT volumes were estimated by stereological Cavalieri sections and compared for overlap.
Nonbound 131I-TM-601 was eliminated by 48 h after injection with the remaining radiolabeled peptide bound to tumor for at least 6-8 d. Biologic decay rates from 24 to 168 h after injection were only slightly shorter than the physical decay of 131I (6.3 vs. 8.0 d). A comparison of tumor volume estimates using all 3 imaging parameters indicated that 131I-TM-601-determined tumor volumes more closely paralleled T2 volumes than T1-Wc volumes. Overlap between coregistered MRI and SPECT scans corroborated the presence of radiolabeled peptide in the vicinity of infiltrating tumor up to 168 h after injection.
131I-TM-601 provides a reliable estimate for primary tumor extent. Further modification of this radiopeptide with other better imaging isotopes may provide an important tool for determining tumor extent and differentiating regions of viable tumor from necrosis.
TM - 601是一种36个氨基酸的肽，可选择性地与胶质瘤细胞结合，但不与正常脑实质结合。对成年复发性高级别胶质瘤患者进行了腔内注射131I - TM - 601的I/II期临床试验，以确定这种潜在治疗方法的生物分布和毒性。我们评估了该试验的影像学和生物分布数据，以评估131I - TM - 601是否有助于确定肿瘤范围。
成年复发性高级别胶质瘤患者在手术后2 - 4周接受肿瘤切除、植入腔内储液器，并单次注射370 MBq（10 mCi）131I - TM - 601（0.25 - 1.0 mg的131I - TM - 601）。在注射后第0、1、2、3和6 - 8天进行全身平面扫描和全脑SPECT扫描。使用图像分析软件将切除后的MR图像与SPECT扫描进行配准。分析了放射性从体内和腔隙部位的衰减率以及生物消除情况。通过体视学卡瓦列里切片估计T1加权钆增强（T1 - Wc）、T2加权（T2）和SPECT体积，并比较其重叠情况。
未结合的131I - TM - 601在注射后48小时内被清除，其余放射性标记的肽与肿瘤结合至少6 - 8天。注射后24至168小时的生物衰减率仅略短于131I的物理衰减率（6.3天对8.0天）。使用所有3种成像参数对肿瘤体积估计值进行比较表明，131I - TM - 601确定的肿瘤体积与T2体积的平行度高于T1 - Wc体积。配准后的MRI和SPECT扫描之间的重叠证实，注射后长达168小时，浸润性肿瘤附近存在放射性标记的肽。
131I - TM - 601为原发性肿瘤范围提供了可靠的估计。用其他更好的成像同位素对这种放射性肽进行进一步修饰，可能为确定肿瘤范围以及区分存活肿瘤区域与坏死区域提供重要工具。
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