title: Influence of subcutaneous fat in surface heating of ultrasonic diagnostic transducers.
abstract: The transducers of diagnostic ultrasonic equipment generate undesired local heating at the applied part of the transducer surface. The assessment of this heating is fundamental in warranting patient safety. On the standard IEC 60601-2-37, methods have been established for the reliable measurement of heating, where three tissue models based on tissue-mimicking materials are recommended: soft tissue mimic only, bone mimic close to the surface of soft tissue, and skin mimic at the surface of soft tissue. In the present work, we compared the last-mentioned tissue model with a new one using a layer of porcine subcutaneous fat inserted between the soft tissue and skin-mimicking materials. We verify significant statistical differences between models, with the average temperature rise measured for the tests without subcutaneous fat at 6.7 °C±1.7 °C and for the ones with subcutaneous fat at 8.9 °C±1.8 °C (k=2; p=0.95). For each model, the procedure was performed 10 times in repeatability conditions of measurement. It has been suggested that the influence of subcutaneous fat for external transducers heating evaluation should be considered, as the presence of many millimeters of subcutaneous fat is a common condition in patients. Otherwise, the transducer surface heating and, therefore, the risk to the patient may be underestimated.
authors.affiliation: Laboratory of Ultrasound/National Institute of Metrology, Quality and Technology, Nossa Senhora das Graças Ave. 50, Duque de Caxias 25250-020, Rio de Janeiro, Brazil; Institute for Nuclear Science Applied to Health & Institute of Biomedical Imaging and Life Science, University of Coimbra, Azinhaga de Santa Comba, Coimbra 3000-548, Coimbra, Portugal. Electronic address: lorena.petrella@gmail.com.
authors.forename: Lorena I
authors.initials: LI
authors.lastname: Petrella
authors.affiliation: Laboratory of Ultrasound/National Institute of Metrology, Quality and Technology, Nossa Senhora das Graças Ave. 50, Duque de Caxias 25250-020, Rio de Janeiro, Brazil; Nature and Biologic Science Center/Federal University of Acre, BR 364, Km 04, Rio Branco 69920-900, Acre, Brazil.
authors.forename: Luis E
authors.initials: LE
authors.lastname: Maggi
authors.affiliation: Laboratory of Ultrasound/National Institute of Metrology, Quality and Technology, Nossa Senhora das Graças Ave. 50, Duque de Caxias 25250-020, Rio de Janeiro, Brazil.
authors.forename: Raquel M
authors.initials: RM
authors.lastname: Souza
authors.affiliation: Laboratory of Ultrasound/National Institute of Metrology, Quality and Technology, Nossa Senhora das Graças Ave. 50, Duque de Caxias 25250-020, Rio de Janeiro, Brazil.
authors.forename: André V
authors.initials: AV
authors.lastname: Alvarenga
authors.affiliation: Laboratory of Ultrasound/National Institute of Metrology, Quality and Technology, Nossa Senhora das Graças Ave. 50, Duque de Caxias 25250-020, Rio de Janeiro, Brazil.
authors.forename: Rodrigo P B
authors.initials: RP
authors.lastname: Costa-Félix
mesh_terms: D040761:Biomimetic Materials; D004867:Equipment Design; D004869:Equipment Safety; D006358:Hot Temperature; D050151:Subcutaneous Fat / Q000000981:diagnostic imaging*; D013814:Thermal Conductivity; D013817:Thermography; D014159:Transducers; D014463:Ultrasonography / Q000295:instrumentation; D035501:Uncertainty
keywords: Heating; Metrology; Subcutaneous fat; Thermal hazard; Ultrasonic transducer