Temperature superposition for fast computation of 3D temperature distributions during optimization and planning of interstitial ultrasound hyperthermia treatments.
Temperature superposition for fast computation of 3D temperature distributions during optimization and planning of interstitial ultrasound hyperthermia treatments.
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DOI：
10.3109/02656736.2012.662666
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发表时间：
2012
期刊：
影响因子：
--
通讯作者：
Diederich CJ
中科院分区：
文献类型：
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作者：
Salgaonkar VA;Prakash P;Diederich CJ
开发了一种温度叠加方法，用于快速优化和规划间质热疗治疗，使用集成在 HDR 近距离治疗导管内的对流冷却多换能器超声治疗器。使用有限元方法预先计算能够定向加热的各个管状传感器产生的稳态温度分布。由多施用器植入产生的复合温度分布近似为预先计算的温度分布的叠加和。还使用精确但计算成本昂贵的 FEM 方法（此处视为验证标准）计算多施用器植入物产生的复合温度分布。这两种方法都用于对一系列测试植入物几何形状和代表性患者病例[前列腺 (n = 13) 和子宫颈 (n = 2) 的 HDR 植入物] 进行温度计算，并为后者创建了优化的治疗计划。在临床相关声强度 (0.3 – 2.0 W/cm2) 和血液灌注 (2 kg/m3/s) 下的测试植入物中，通过叠加法和 FEM 方法计算出的温度差异低于 0.37 °C（95% 置信度）。 41 °C 等温体积差异低于 8.3%。基于叠加的优化和 FEM 正向计算（混合计划）的完成速度比仅 FEM 计划（FEM 优化 + FEM 正向）快 4 – 7 倍。两个计划的平均 T90、T50 和 T10 值分别在 0.3 °C、0.4 °C 和 0.45 °C 以内，平均声强在 0.23 W/cm2 以内。温度叠加为间质超声热疗治疗的前瞻性或优化规划提供了一种快速技术，其计算结果与更准确但耗时的 FEM 方法相当。
A temperature superposition method has been developed for fast optimization and planning of interstitial hyperthermia treatments with convectively-cooled multi-transducer ultrasound applicators integrated within HDR brachytherapy catheters. Steady-state temperature distributions produced by individual tubular transducers capable of directional heating were pre-computed using FEM methods. The composite temperature distributions generated by multi-applicator implants were approximated as superposition sums of the pre-computed temperature profiles. Composite temperature distributions produced by the multi-applicator implants were also computed using accurate but computationally expensive FEM methods (considered here as the validation standard). Both methods were used for temperature calculation on a range of test implant geometries and representative patient cases [HDR implants in prostate (n = 13) and cervix (n = 2)], with optimized treatment plans created for the latter. Difference between temperatures calculated by the superposition and FEM methods was below 0.37 °C (95% confidence) in test implants at clinically relevant acoustic intensities (0.3 – 2.0 W/cm2) and blood perfusion (2 kg/m3/s). Difference in 41 °C isothermal volumes was below 8.3%. Superposition based optimizations followed by FEM forward calculations (hybrid plans) were completed 4 – 7 times faster than FEM-only plans (FEM optimization + FEM forward). Mean T90, T50 and T10 values from both plans were within 0.3 °C, 0.4 °C and 0.45 °C respectively, and the mean acoustic intensities were within 0.23 W/cm2. Temperature superposition provides a fast technique for forward or optimized planning of interstitial ultrasound hyperthermia treatments with calculations comparable to more accurate but time consuming FEM methods.