超声治疗学>>Chap.8HIFUTherapeuticTechnology1TechnicalAspects ofHIFUWhat is HIFU?Highenergy(intensity)ultrasound beamBrought to tight focus at a distance from source.Absorption ofenergy leads to tissue heatingCauses very localized temperature rise at focus.Sharplydemarcated area of coagulativenecrosis. No damage to overlying and surrounding tissue.Ideal for manipulation as noninvasive tool.重庆医科大学生物医学工程系
超声治疗学 >>Chap. 8 HIFU Therapeutic Technology 1 重庆医科大学生物医学工程系 Technical Aspects of HIFU High energy (intensity) ultrasound beam. Brought to tight focus at a distance from source. Absorption of energy leads to tissue heating. Causes very localized temperature rise at focus. Sharply demarcated area of coagulative necrosis. No damage to overlying and surrounding tissue. Ideal for manipulation as noninvasive tool. What is HIFU?
超声治疗学>>Chap.8HIFUTherapeutic Technology]Ultrasound（in tissueIncidentBeamImageAttenuation0AbsorptionScatterAbsorption60-80%HEAT重庆医科大学生物医学工程系
超声治疗学 >>Chap. 8 HIFU Therapeutic Technology 1 重庆医科大学生物医学工程系 Ultrasound ( in tissue )
超声治疗学>>Chap.8HIFUTherapeuticTechnology1Ultrasound (Intensity or Power)DIAGNOSIS:-0.02WTissue informationPOWERWithout biological effectTHERAPY:Deliberate (beneficial)biological effect(reversible or irreversible)Functional modification~200WSURGERY:Cell killing10.000 timesmoreenergy重庆医科大学生物医学工程系
超声治疗学 >>Chap. 8 HIFU Therapeutic Technology 1 重庆医科大学生物医学工程系 Ultrasound (Intensity or Power) POWER DIAGNOSIS: Tissue information Without biological effect THERAPY: Deliberate (beneficial) biological effect (reversible or irreversible) Functional modification SURGERY: Cell killing ~0.02W ~200W 10,000 times more energy
超声治疗学>>Chap,8HIFUTherapeuticTechnology1Table 14.1Output characteristics of ultrasound devicesFrequencyTypicalTypical dutyPowerextemal probesintra-cavitary probesTypefactor(mW)Spatial peak,range (MHz)source areapeak negativespatial peak,peak negative(mm)acoustictemporal averagetemporal averageacousticpressureIntensity Iapuintensity Ispiuppressure p(MPa)(mWcm")(MPa)(mWcm2)DiagnosticPulse-echoB-mode1-20100-30000.0014-256(64)1-1330(175)0.45-5.54(2.09)0.8-284(64.60)0.66-3.5(2.32)M-mode1-20100-30000.0010.5-213(46)4.2-6.04(127)0.45-5.54(2.09)2.0-210(62.7)0.66-3.5(2.32)Doppler100>5-300.012-4Fetal heart detector100Pulsed Doppler5-100.0111-324(144)36-9080(1570)0.67-5.32(2.18)97.1-1440(747)0.97-3.53(2.26)100Colour flow5-100.0135-295(138)21-2150(429)0.46-4.25(2.41)0.97-3.53(2.26)1.14-3.04(2.47)TherapeuticPhysiotherapy30010.75-30-15000Continuouswave0.2Pulsed0.75-33000-30005000.50.5-10500012000005SurgerySource: from Henderson et al.(1995) and Whittingham (2000)重庆医科大学生物医学工程系
超声治疗学 >>Chap. 8 HIFU Therapeutic Technology 1 重庆医科大学生物医学工程系 Table 14.1 Output characteristics of ultrasound devices Equipment Frequency Typical Typical duty Power external probes intra-cavitary probes Type range (MHz) source area factor (mW) Spatial peak, peak negative spatial peak, peak negative (mm2) temporal average acoustic temporal average acoustic pressure Intensity Ispta pressure p- intensity Ispta p- (mW cm-2) (MPa) (mW cm-2) (MPa) Diagnostic Pulse-echo B-mode 1-20 100-3000 0.001 4-256(64) 1-1330(175) 0.45-5.54(2.09) 0.8-284(64.60) 0.66-3.5(2.32) M-mode 1-20 100-3000 0.001 0.5-213(46) 4.2-6.04(127) 0.45-5.54(2.09) 2.0-210(62.7) 0.66-3.5(2.32) Doppler Fetal heart detector 2-4 100 1 5-30 0.01 Pulsed Doppler 5-10 100 0.01 11-324(144) 36-9080(1570) 0.67-5.32(2.18) 97.1-1440(747) 0.97-3.53(2.26) Colour flow 5-10 100 0.01 35-295(138) 21-2150(429) 0.46-4.25(2.41) 0.97-3.53(2.26) 1.14-3.04(2.47) Therapeutic Physiotherapy Continuous wave 0.75-3 300 1 0-15000 Pulsed 0.75-3 300 0.2 0-3000 500 0.5 Surgery 0.5-10 5000 1 200000 5 Source: from Henderson et al.(1995) and Whittingham (2000)
超声治疗学>>Chap.8HIFUTherapeuticTechnology1Ultrasound (Focusing)PHERIGLENSTRANSDUCERUltrasound beamsmaybefocused by curving theELECTRICREFLECTORFOCUSINGpiezoelectric plate or byinterposing a lens or reflectorbetween aflatplate andthetarget. A phased array oftransducers is focusedelectronically重庆医科大学生物医学工程系
超声治疗学 >>Chap. 8 HIFU Therapeutic Technology 1 重庆医科大学生物医学工程系 Ultrasound (Focusing) Ultrasound beams may be focused by curving the piezoelectric plate or by interposing a lens or reflector between a flat plate and the target. A phased array of transducers is focused electronically