Theoretical investigation of transgastric and intraductal approaches for ultrasound-based thermal therapy of the pancreas

Table 1 Material properties of tissues. ƒ represents frequency, in units of MHz

Medium	Density (kg/m³)	Attenuation (Np/m)	Thermal conductivity (W/m/K)	Specific heat (J/kg/K)	Perfusion rate (kg/m³/s)
Tumor	1050^a	10 ƒ [52, 65]	.51^a	3200^a	4.5 [51, 66–68]
Pancreas	1050 [52]	11.9 ƒ^0.78 [52]	.51 [52]	3200 [69]	10 [52]
Duodenal wall	1050 [52]	5 ƒ	.53 [52, 69]	3700 [69–71]	16.7 [52, 69]
Stomach wall	1060 [52, 69]	5 ƒ	.54 [52, 69]	3700 [69]	6.8 [52, 69]
Water, pancreatic juices, and gastric contents	1010 [52, 72]	0.025 ƒ² [52]	.58	4000	0
Blood	N/A	1.6 ƒ^1.21 [52]	N/A	3600 [52]	N/A
Liver	1050 [52]	4.5 ƒ [16]	.51 [52]	3600 [16]	15 [16]
Kidney	1050 [52]	6 ƒ [52]	.54 [52]	3700 [52]	68.9 [52]
Spleen	1050 [52]	13.2 ƒ [52]	.54 [52]	3700 [52]	22.1 [52]
Bone	1420 [52]	105 ƒ [52]	.38 [52]	1700 [73]	0.89 [74]
Renal calcifications	1990 [52]^b	105 ƒ [52]^b	.5 [52]^c	1300 [52]^b	0
Bowel	1040 [52]	5.6 ƒ [52]	0.56 [52]	3600 [69]	16.4 [52]
Other soft tissue	1050 [52]	6.4 ƒ [52]	.49 [52]	3400 [52]	3 [52]

Properties of normal pancreatic tissue were used for some pancreatic tumor properties (^a). The acoustic attenuation of various neoplasms was used to estimate the attenuation in pancreatic tumors. Because the specific heat of water is very different from those of tissue and biological fluids, an intermediate value was used for the specific heat of water, pancreatic juices, and gastric contents. Attenuation of the stomach and duodenal walls were estimated from measurements performed in porcine stomach tissue. Properties for whole or cortical bone (^b) were used for some calcification properties, and properties for calcified arterial plaques were used for another (^c)

ISSN: 2050-5736