Mason R P, Hunjan S, Le D, Constantinescu A, Barker B R, Wong P S, Peschke P, Hahn E W, Antich P P
Department of Radiology, U.T. Southwestern Medical Center, Dallas, TX 75235-9058, USA.
Int J Radiat Oncol Biol Phys. 1998 Nov 1;42(4):747-50. doi: 10.1016/s0360-3016(98)00306-x.
Therapeutic success could be enhanced if therapy were tailored to the characteristics of specific tumors. We have been developing novel approaches to measuring tumor oxygen tension in vivo, and recently reported a method based on 19F nuclear magnetic resonance (NMR) spin lattice echo planar imaging (EPI) relaxometry of hexafluorobenzene (HFB). We have now examined the feasibility of monitoring dynamic changes in regional tumor oxygenation in response to respiratory challenge. Preliminary data in one tumor show distinct differences before and subsequent to irradiation.
Dunning prostate adenocarcinoma R3327-AT1 was grown in the form of pedicles on the foreback of male Copenhagen rats. When the tumors reached approximately 1 cm diameter, HFB (40 microl) was administered by direct intratumoral injection deliberately dispersed to interrogate both central and peripheral regions. Local pO2 was determined using pulse burst saturation recovery 19F NMR EPI on the basis of the spin lattice relaxation rate.
Interrogation of both central and peripheral regions of tumors showed bimodal distribution for oxygenation, including many voxels with pO2 < 15 torr. Altering the inspired gas to 100% O2 produced significant elevation for regions with initially high pO2 (P < 0.01), but the temporal course of dynamic changes varied for each voxel. Many voxels with low pO2 showed little response. Following irradiation (20 Gy), tumor oxygenation was significantly elevated and remained high for at least 10 h.
We believe this method provides a valuable new approach to investigate tumor oximetry that may extend our understanding of tumor physiology, and could have prognostic value.
如果根据特定肿瘤的特征量身定制治疗方案，治疗成功率可能会提高。我们一直在开发测量体内肿瘤氧张力的新方法，最近报道了一种基于六氟苯（HFB）的19F核磁共振（NMR）自旋晶格回波平面成像（EPI）弛豫测量法。我们现在研究了监测区域肿瘤氧合对呼吸刺激反应的动态变化的可行性。一个肿瘤的初步数据显示了照射前后的明显差异。
将邓宁前列腺腺癌R3327-AT1以蒂状形式种植在雄性哥本哈根大鼠的背部。当肿瘤直径达到约1厘米时，通过直接瘤内注射给予HFB（40微升），有意将其分散以检测中央和周边区域。基于自旋晶格弛豫率，使用脉冲猝发饱和恢复19F NMR EPI测定局部pO2。
对肿瘤中央和周边区域的检测显示氧合呈双峰分布，包括许多pO2<15托的体素。将吸入气体改为100%O2会使初始pO2较高的区域显著升高（P<0.01），但每个体素的动态变化时间进程各不相同。许多pO2较低的体素反应很小。照射（20 Gy）后，肿瘤氧合显著升高并至少保持10小时。
我们认为这种方法为研究肿瘤血氧测定提供了一种有价值的新方法，可能会扩展我们对肿瘤生理学的理解，并且可能具有预后价值。
