Acker J C, Dewhirst M W, Honoré G M, Samulski T V, Tucker J A, Oleson J R
Duke University School of Medicine, Durham, NC 27710.
Int J Hyperthermia. 1990 Mar-Apr;6(2):287-304. doi: 10.3109/02656739009141139.
Laser Doppler flowmetry is a simple method of determining, directly and continuously, tissue blood flow. However, its applicability to monitoring tumour blood flow interstitially during hyperthermia treatments is still being evaluated. The purposes of this study were to physically characterize the measurement probes, to evaluate potential sources of artifact with the interstitial use of the probes during hyperthermia treatment, and to obtain measurements in human tumours during hyperthermia sessions. The accuracy of the method in quantifying blood flow, velocity and volume during hyperthermia was found to be unaffected by heating the measurement probe to 42-46 degrees C or by exposing it to various intensities of 915 MHz microwave fields (10-40 W), or 1 MHz ultrasound fields. Catheter insertion methods were developed to place the flow probes interstitially in tumours. Tissue damage was confined to a distance of no greater than 0.12 mm away from the catheter tract, and physical evidence of vascular disruption was within a distance of 0.05 mm as measured in a rat tumour model. This degree of damage/disruption is unlikely to affect LDF measurements which represent blood flow averaged over a 1.0-1.5 mm radius from the probe tip. Concurrently, the device was used to monitor tumour blood flow parameters interstitially in human subjects during hyperthermia treatments given in combination with conventional radiotherapy. Blood-flow data from multiple sites of measurement showed marked heterogeneity within individual tumours (up to 55-fold differences) and between different tumours (greater than 100-fold differences). Measurements made by translating the probe along a tumour radius, beginning at the tumour core and advancing to the tumour edge, were consistent with a two-component tumour perfusion model (shell and core). Data are presented from one patient illustrating a persistent change in perfusion distribution during the hyperthermia treatment course, which occurred concomitantly with increases in thermal data. These results suggest that the technique might be of value in monitoring change in flow between treatments. Responses during hyperthermia treatment sessions were also investigated. Four temporal patterns of flow were observed, ranging from a steady increase in flow to a plateau level to a steady drop in flow during heating. These patterns were not well correlated with average temperature recorded at the site of flow measurement. Further study is needed to determine if this LDF technique is to be useful for evaluation of heat transfer by blood perfusion.
激光多普勒血流仪是一种直接连续测定组织血流的简单方法。然而，其在热疗期间用于监测肿瘤间质血流的适用性仍在评估中。本研究的目的是对测量探头进行物理特性描述，评估热疗期间探头间质使用时伪像的潜在来源，并在热疗过程中获取人体肿瘤的测量值。结果发现，在热疗期间，将测量探头加热至42 - 46摄氏度、使其暴露于各种强度的915 MHz微波场（10 - 40 W）或1 MHz超声场中，该方法在量化血流、速度和体积方面的准确性不受影响。开发了导管插入方法，将血流探头间质放置在肿瘤中。在大鼠肿瘤模型中测量发现，组织损伤局限于距导管路径不超过0.12毫米的距离内，血管破坏的物理证据在0.05毫米的距离内。这种程度的损伤/破坏不太可能影响代表从探头尖端起半径为1.0 - 1.5毫米范围内平均血流的激光多普勒血流仪测量值。同时，该设备用于在与传统放疗联合进行热疗期间，间质监测人体受试者的肿瘤血流参数。来自多个测量部位的血流数据显示，个体肿瘤内部（差异高达55倍）以及不同肿瘤之间（差异大于100倍）存在明显的异质性。通过将探头沿肿瘤半径从肿瘤核心向肿瘤边缘平移进行测量，结果与双组分肿瘤灌注模型（外壳和核心）一致。给出了一名患者的数据，说明了热疗过程中灌注分布的持续变化，这与热数据的增加同时发生。这些结果表明，该技术在监测治疗间血流变化方面可能具有价值。还研究了热疗期间的反应。观察到四种血流时间模式，从加热期间血流稳定增加到平稳水平再到稳定下降。这些模式与血流测量部位记录的平均温度相关性不佳。需要进一步研究以确定这种激光多普勒血流仪技术是否可用于评估血液灌注的热传递。
