Transurethral ultrasound applicators with directional heating patterns for prostate thermal therapy:: In vivo evaluation using magnetic resonance thermometry
Transurethral ultrasound applicators with directional heating patterns for prostate thermal therapy:: In vivo evaluation using magnetic resonance thermometry
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DOI：
10.1118/1.1639959
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发表时间：
2004-02-01
期刊：
影响因子：
3.8
通讯作者：
Hazle, JD
中科院分区：
文献类型：
--
作者：
Diederich, CJ;Stafford, RJ;Hazle, JD
一种基于导管的经尿道超声施加器，具有角度定向加热模式，已被设计用于前列腺热治疗，并在犬前列腺中使用MRI进行体内评价，以监测和评估性能。将超声换能器阵列（3.5 mm直径管状换能器，180度有源扇区，类似于7.5 MHz）集成到柔性递送导管（4 mm OD），并封装在可膨胀球囊（35 mm X 10 mm OD，80 ml min（-1）环境水）内，用于前列腺尿道的耦合和冷却。这些器械用于热凝固犬前列腺的目标部分（n = 2），同时使用MR热成像（MRTI）监测治疗。MRI还用于靶点定义、施源器定位和治疗后靶点活力评价。磁共振成像是基于复杂的相位差映射技术，使用交错梯度回波平面成像序列与脂质抑制。磁共振成像衍生的温度分布，热剂量暴露，T1对比增强的MR图像，和切片前列腺的组织学被用来定义破坏的组织区域和表征的三维加热模式。超声探头在靶组织内产生类似于180度的定向热凝固区，在15分钟内径向延伸15-20 mm至前列腺外边界。17 mm和24 mm的换能器激活长度分别产生轴向延伸18 mm和25 mm的连续凝固区。测得峰值温度约为90 ℃，与50 ℃- 52 ℃相似，对应于外边界t（43）= 240 min，处理时间约为15 min。这些设备与MRI兼容，并且当与多平面MRTI耦合时，提供用于选择性地控制前列腺中的治疗性热处理的长度和扇形角的手段。(C)2004年美国医学物理学家协会。
A catheter-based transurethral ultrasound applicator with angularly directional heating patterns has been designed for prostate thermal therapy and evaluated in canine prostate in vivo using MRI to monitor and assess performance. The ultrasound transducer array (3.5 mm diameter tubular transducers, 180degrees active sectors, similar to7.5 MHz) was integrated to a flexible delivery catheter (4 mm OD), and encapsulated within an expandable balloon (35 mm X 10 mm OD, 80 ml min(-1) ambient water) for coupling and cooling of the prostatic urethra. These devices were used to thermally coagulate targeted portions of the canine prostate (n = 2) while using MR thermal imaging (MRTI) to monitor the therapy. MRI was also used for target definition, positioning of the applicator, and evaluation of target viability post-therapy. MRTI was based upon the complex phase-difference mapping technique using an interleaved gradient echo-planar imaging sequence with lipid suppression. MRTI derived temperature distributions, thermal dose exposures, T1-contrast enhanced MR images, and histology of sectioned prostates were used to define destroyed tissue zones and characterize the three-dimensional heating patterns. The ultrasound applicators produced similar to180degrees directed zones of thermal coagulation within targeted tissue which extended 15-20 mm radially to the outer boundary of the prostate within 15 min. Transducer activation lengths of 17 mm and 24 mm produced contiguous zones of coagulation extending axially similar to18 rum and similar to25 mm from base to apex, respectively. Peak temperatures around 90 degreesC were measured, with similar to50 degreesC - 52 degreesC corresponding to outer boundary t(43) = 240 min at - 15 min treatment time. These devices are MRI compatible, and when coupled with multiplanar MRTI provide a means for selectively controlling the length and sector angle of therapeutic thermal treatment in the prostate. (C) 2004 American Association of Physicists in Medicine.