In vitro heating of human fetal vertebra by pulsed diagnostic ultrasound.
The temperature rise generated at the surface of unperfused human fetal vertebrae in vitro by an ultrasound beam with characteristics typical of those used in pulsed Doppler examinations has been measured. The bone samples were from fetuses that ranged in age from 14 to 39 weeks, dating from the last menstrual period. The samples were embedded in agar gel and the temperature rise at their surface was measured using a 50-microm diameter K-type thermocouple. The power in the ultrasound beam was 50 +/- 2 mW and the -6 dB diameter was 2.9 mm. The temperature rise at 295 s ranged from 0.6 degrees C in the youngest sample to 1.8 degrees C in the oldest. Approximately 70% of the temperature rise occurred in the first min.
Doody
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C
School of Design, Engineering and Computing, Bournemouth University, Poole, UK. cdoody@bournemouth.ac.uk
Porter
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H
Duck
F A
FA
Humphrey
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VF
D005865:Gestational Age; D006358:Hot Temperature; D006801:Humans; D066298:In Vitro Techniques; D013904:Thoracic Vertebrae / Q000000981:diagnostic imaging*; D018617:Ultrasonography, Doppler, Pulsed; D016216:Ultrasonography, Prenatal