Therapeutic Ultrasound Therapeutic Ultrasound Setting the Stage for Evidence Setting the Stage for Evidence Based Clinical Trials Based Clinical Trials Johns LD, Straub SJ, *LeDet LeDet EG, * Howard S and Zaino A: EG, * Howard S and Zaino A: Johns LD, Straub SJ, * Quinnipiac University, Hamden Connecticut and Quinnipiac University, Hamden Connecticut and Onda Corporation*, Sunnyvale, California. Corporation*, Sunnyvale, California. Onda Funded by Quinnipiac University, EATA & NATA- -REF REF Funded by Quinnipiac University, EATA & NATA
Clinical Indications: Inferential Methods Results Methods Results Cell Biology Studies: Strong Support Cell Biology Studies: Strong Support Clinical Trials: Inconclusive Clinical Trials: Inconclusive Tissue Heating: Conclusive ‘BUT’ Tissue Heating: Conclusive ‘BUT’ Variable Variable
Clinical Variability Clinical Variability Human – –vs vs- - Technology Technology Human Technique Technique – Treatment Area, Coupling Medium Treatment Area, Coupling Medium – Differences between manufacturers Differences between manufacturers – – Ultrasound field produced Ultrasound field produced – – BNR, ERA, crystals, Technology, etc BNR, ERA, crystals, Technology, etc – – Calibrations Calibrations + + 15 15- -20 % of baseline 20 % of baseline 30 30- -40% difference between heads 40% difference between heads Or….more fundamental issues? Or….more fundamental issues?
Clinical Assumption Clinical Assumption Equality Between: Equality Between: 1. Manufacturers Manufacturers 1. 2. Various Heads within a Manufacturer Various Heads within a Manufacturer 2. BNR and ERA are Predictive BNR and ERA are Predictive True or or False False True
Variability Between Manufacturers Variability Between Manufacturers 3 MHz N=1 Head 3 MHz N=1 Head W/cm 2 o C/min BNR Min Depth Temp 5.8 o C " Omnisound 3.7 1.0 10 1.2 cm 0.58 3.9 o C " Forte 2.3 1.0 10 1.2 cm 0.39 6.0 o C ` Omnisound 3.9 1.5 6 1.6 cm 1.00 3.7 o C ` Excel <4.0 1.5 6 1.6 cm 0.62 3.8 o C ` Dynatron <6.0 1.5 6 1.6 cm 0.63 “Holcomb etal 2003, JAT 38(1):24-27. 49% difference in heating rate ` Merrick etal 2003, JOSPT 33:379-385. 59 & 61% difference in heating rate
Variability Between Heads??? Variability Between Heads??? BNR W/cm 2 Min Depth Temp o C/min ~Omnisound 1.8 1.5 12.3 5.0 cm 3.5 o C 0.28 ^Omnisound 2.2 1.5 10.0 5.0 cm 3.9 o C 0.39 Difference Difference 39% 39% in heating in heating 1 MHz rate 1 MHz rate ~ Rose,etal., JAT, 31(2) 1996, pages 139-143 ^ Draper, etal. JOSPT. 21(3) 1995, page 153-157
Clinical Assumption Clinical Assumption Equality Between: Equality Between: 1. Manufacturers Manufacturers 1. 2. Various Heads within a Manufacturer Various Heads within a Manufacturer 2. BNR and ERA are Predictive BNR and ERA are Predictive Appear to be False Appear to be False
2 Possible Factors Leading to Variability in 2 Possible Factors Leading to Variability in Clinical Outcomes Clinical Outcom W/cm 2 2 1) Determination of SAI 1) Determination of SAI W/cm – Total Power Total Power – Display of total power – –vs vs- - actual total power produced actual total power produced Display of total power SAI variability (+ + 20%) 20%) SAI variability ( – ERA ERA – group means in the software to determine SAI group means in the software to determine SAI SAI variability (+ SAI variability ( + 20 20- -25%) 25%) 2) Distribution of acoustical amplitudes 2) Distribution of acoustical amplitudes – Variability in tissue heating Variability in tissue heating –
Range of Potential SAI Values Range of Potential SAI Values While Staying Within Manufacturer Limits While Staying Within Manufacturer Limits Watts + 20% *Heating ERA cm 2 4.0 5.0 6.0 Rate 5.0 0.80* 1.00 1.20 0.5 4.0 1.00 1.25* 1.50 0.75 0.75 3.0 1.33 1.67 2.00* 1.4 Digital indicator on machines reads 1.25 W/cm 2 3 MHz Heating Rate o C/min in muscle (based upon Draper) 150% difference between high and low SAI
Field Testing of Clinical Units Field Testing of Clinical Units 44% Failed Calibration or Electrical Safety (N=45) 44% Failed Calibration or Electrical Safety (N=45) Daniel & Rupert, Daniel & Rupert, J.Man.Phys.Ther J.Man.Phys.Ther 26(3):171 26(3):171- -175, 2003 175, 2003 39% Failed Calibration Standard (N=32) 39% Failed Calibration Standard (N=32) Artho Artho, , etal etal, Physical Therapy82(3):257 , Physical Therapy82(3):257- -263, 2002 263, 2002 69% Failed Calibration Standard (N=85) 69% Failed Calibration Standard (N=85) Pye Pye & Milford, Ultrasound, Med Biol. 23:347 & Milford, Ultrasound, Med Biol. 23:347- -359, 1994 359, 1994 56% Failed Calibration Standard (N=43) 56% Failed Calibration Standard (N=43) Lloyd & Evans, Physiotherapy, 74:56 Lloyd & Evans, Physiotherapy, 74:56- -61, 1988 61, 1988 81% Failed Calibration Standard (N=26) 81% Failed Calibration Standard (N=26) Snow, Physiotherapy Canada, 34:185- -189, 1982 189, 1982 Snow, Physiotherapy Canada, 34:185 85% Failed Calibration Standard (N=58) 85% Failed Calibration Standard (N=58) Stewart, etal etal, Phys , Phys Ther Ther, 54:707 , 54:707- -715, 1974 715, 1974 Stewart,
Clinical Assumption Clinical Assumption New transducers are more accurate? New transducers are more accurate? Buy new transducers and test Buy new transducers and test
Experimental Design Experimental Design Chattanooga Intellect Chattanooga Intellect Model # 78047 Model # 78047 Frequency: 1 & 3 MHz Frequency: 1 & 3 MHz 5 cm 2 2 Head size: Head size: 5 cm N= 7 Heads N= 7 Heads Manufacturer Reported Manufacturer Reported – BNR: BNR: 4:1 Max – 4:1 Max 4.0 cm 2 2 – ERA: ERA: – 4.0 cm
Independent Analysis of Independent Analysis of Ultrasound Transducers at 1.0 MHz Ultrasound Transducers at 1.0 MHz ERA in cm 2 SAI in W/cm 2 Transducer Watts Planar BNR 35661 3.62 5.1 1.4 3.65 35663 3.88 5.6 1.4 2.79 35664 4.38 5.4 1.2 2.87 35986 4.04 5.1 1.3 4.51 37952 4.13 5.0 1.2 5.09 37953 4.34 5.5 1.3 4.48 37954 3.85 5.4 1.4 5.85 Mean 4.03 + 0.27 5.30 + 0.23 1.3 + 0.10 4.18 + 1.14 Manufacturer reported ERA 4.00 + 1.0 Watts calibrated to 5.0 + 0.75 or 15% SAI, digital indicator on machines reads 1.2 W/cm2
Transducer Profiling of ERA and Generation of Watts at 1 MHz 1 MHz ERA ERA Total Power SAI Reported Measured Measured Measured Mettler 5.00 + 1.00 4.01 + 0.34 5.45 + 0.20 1.36 + 0.11 Chatt.New 4.00 + 1.00 3.16 + 0.66 3.97 + 0.41 1.26 + 0.44 Rich-Mar 5.00 + 1.00 3.83 + 0.21 4.57 + 0.23 1.19 + 0.07 Xltek 5.00 + 0.75 4.61 + 0.49 5.14 + 0.23 1.12 + 0.15 Chattanooga 4.00 + 1.00 3.97 + 0.25 4.28 + 0.43 1.09 + 0.13 Omnisound 4.45 + 0.67 5.03 + 0.58 4.95 + 0.38 0.99 + 0.16 Dynatronics 5.00 + 1.00 5.35 + 0.28 4.42 + 0.20 0.83 + 0.06^ Dynatronics ERA was larger than all others ( ERA was larger than all others ( P P <0.05) <0.05) Dynatronics Xltek and and Omnisound Omnisound ERA was larger than ERA was larger than Mettler Mettler, Chattanooga and Rich , Chattanooga and Rich- -Mar ( Mar ( P P <0.05) <0.05) Xltek Overall ERA at 1MHz was smaller than at 3MHz ( P Overall ERA at 1MHz was smaller than at 3MHz ( P <0.005) <0.005) ERA in cm 2 , Total Power in Watts and SAI in W/cm 2 *SAI when the ultrasound generator reads 1.0 Watts/cm 2
Transducer Profiling of ERA and Generation of Watts at 1 MHz 1 MHz ERA ERA Total Power SAI Reported Measured Measured Measured Mettler 5.00 + 1.00 4.01 + 0.34 5.45 + 0.20 1.36 + 0.11 Chatt.New 4.00 + 1.00 3.16 + 0.66 3.97 + 0.41 1.26 + 0.44 Rich-Mar 5.00 + 1.00 3.83 + 0.21 4.57 + 0.23 1.19 + 0.07 Xltek 5.00 + 0.75 4.61 + 0.49 5.14 + 0.23 1.12 + 0.15 Chattanooga 4.00 + 1.00 3.97 + 0.25 4.28 + 0.43 1.09 + 0.13 Omnisound 4.45 + 0.67 5.03 + 0.58 4.95 + 0.38 0.99 + 0.16 Dynatronics 5.00 + 1.00 5.35 + 0.28 4.42 + 0.20 0.83 + 0.06^ *Mettler Mettler SAI was higher than all others ( SAI was higher than all others ( P P <0.05) <0.05) * ^Dynatronics Dynatronics SAI was lower than all others ( SAI was lower than all others ( P P <0.05). <0.05). ^ SAI range across all 66 transducers at 1 MHz was 0.76 to 1.56 SAI range across all 66 transducers at 1 MHz was 0.76 to 1.56 ERA in cm 2 , Total Power in Watts and SAI in W/cm 2 *SAI when the ultrasound generator reads 1.0 Watts/cm 2
% Difference in Mean SAI: 1 MHz % Difference in Mean SAI: 1 MHz Mettler Richmar Xltek Chattanooga Omnisound Dynatronics 1.36 1.19 1.12 1.09 0.99 0.83 Mettler 1.36 0% 14% 21% 25% 37% 64% Richmar 1.19 0% 6% 9% 20% 43% Xltek 1.12 0% 3% 13% 35% Chattanooga 1.09 0% 10% 31% Omnisound 0.99 0% 19% Dynatronics 0.83 0% SAI = W/cm2 SAI = W/cm2
%Difference Between High and Low SAI, 1 MHz Mettler Rich-Mar XlTek Chattanooga Omnisound Dynatronics 1.17 1.09 0.97 0.86 0.88 0.76 33% 105% Mettler 1.56 43% 61% 81% 77% 19% 71% Rich-Mar 1.30 11% 34% 51% 48% 45% XlTeck 1.41 21% 29% 64% 60% 86% 51% Chattanooga 1.30 11% 19% 34% 48% 71% Omnisound 1.14 -3% 5% 18% 33% 30% 50% Dynatronics 0.94 -20% -14% -3% 9% 7% 24% SAI = W/cm2 SAI = W/cm2
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