Scott Serena J, Adams Matthew S, Salgaonkar Vasant, Sommer F Graham, Diederich Chris J
Department of Radiation Oncology, Thermal Therapy Research Group, University of California, San Francisco, 1600 Divisadero Street, Suite H1031, San Francisco, CA 94143-1708 USA.
UC Berkeley - UC San Francisco Graduate Program in Bioengineering, California, USA.
J Ther Ultrasound. 2017 May 3;5:10. doi: 10.1186/s40349-017-0090-2. eCollection 2017.
The goal of this study was to theoretically investigate the feasibility of intraductal and transgastric approaches to ultrasound-based thermal therapy of pancreatic tumors, and to evaluate possible treatment strategies.
This study considered ultrasound applicators with 1.2 mm outer diameter tubular transducers, which are inserted into the tissue to be treated by an endoscopic approach, either via insertion through the gastric wall (transgastric) or within the pancreatic duct lumen (intraductal). 8 patient-specific, 3D, transient, biothermal and acoustic finite element models were generated to model hyperthermia ( = 2) and ablation ( = 6), using sectored (210°-270°, = 4) and 360° ( = 4) transducers for treatment of 3.3-17.0 cm tumors in the head ( = 5), body ( = 2), and tail ( = 1) of the pancreas. A parametric study was performed to determine appropriate treatment parameters as a function of tissue attenuation, blood perfusion rates, and distance to sensitive anatomy.
Parametric studies indicated that pancreatic tumors up to 2.5 or 2.7 cm diameter can be ablated within 10 min with the transgastric and intraductal approaches, respectively. Patient-specific simulations demonstrated that 67.1-83.3% of the volumes of four sample 3.3-11.4 cm tumors could be ablated within 3-10 min using transgastric or intraductal approaches. 55.3-60.0% of the volume of a large 17.0 cm tumor could be ablated using multiple applicator positions within 20-30 min with either transgastric or intraductal approaches. 89.9-94.7% of the volume of two 4.4-11.4 cm tumors could be treated with intraductal hyperthermia. Sectored applicators are effective in directing acoustic output away from and preserving sensitive structures. When acoustic energy is directed towards sensitive structures, applicators should be placed at least 13.9-14.8 mm from major vessels like the aorta, 9.4-12.0 mm from other vessels, depending on the vessel size and flow rate, and 14 mm from the duodenum.
This study demonstrated the feasibility of generating shaped or conformal ablative or hyperthermic temperature distributions within pancreatic tumors using transgastric or intraductal ultrasound.
本研究的目的是从理论上探讨经导管和经胃途径对胰腺肿瘤进行超声热疗的可行性，并评估可能的治疗策略。
本研究考虑使用外径为1.2毫米的管状换能器的超声探头，通过内镜途径将其插入待治疗组织，可经胃壁插入（经胃）或插入胰管腔内（经导管）。生成了8个患者特异性的三维瞬态生物热和声有限元模型，用于模拟热疗（n = 2）和消融（n = 6），使用扇形（210°-270°，n = 4）和360°（n = 4）换能器治疗胰腺头部（n = 5）、体部（n = 2）和尾部（n = 1）直径为3.3 - 17.0厘米的肿瘤。进行了参数研究，以确定作为组织衰减、血液灌注率和与敏感解剖结构距离函数的合适治疗参数。
参数研究表明，直径达2.5厘米或2.7厘米的胰腺肿瘤分别可在10分钟内通过经胃和经导管途径消融。患者特异性模拟表明，使用经胃或经导管途径，在3 - 10分钟内可消融四个样本3.3 - 11.4厘米肿瘤体积的67.1 - 83.3%。对于一个17.0厘米的大肿瘤，使用多个探头位置，经胃或经导管途径在20 - 30分钟内可消融其体积的55.3 - 60.0%。两个4.4 - 11.4厘米肿瘤体积的89.9 - 94.7%可通过经导管热疗治疗。扇形探头可有效地将声输出导向远离并保护敏感结构。当声能导向敏感结构时，探头应距离主动脉等主要血管至少13.9 - 14.8毫米，距离其他血管9.4 - 12.0毫米，具体取决于血管大小和流速，距离十二指肠14毫米。
本研究证明了使用经胃或经导管超声在胰腺肿瘤内产生成形或适形消融或热疗温度分布的可行性。
