'Guidelines for the Safe Use of Ultrasound -Part 1: Medical and Paramedical Applications (1989)'pertaining to the safe use of diagnostic ultrasound devices. Several developments in the past decade have necessitated this update. First, methods have been developed for estimating the maximum temperature elevation in exposed tissues during clinical examinations (see Sections 3.2 and 4.1). These estimates indicated that during some Doppler blood flow examinations, temperature elevations could exceed 1 °C. Computed estimates of maximum temperature elevations have been as high as 6-10 °C. Also, biological effects studies have demonstrated capillary hemorrhaging in vivo in the lungs of several mammalian species (though not humans), as a result of pulsed ultrasound exposures in the range of those available from diagnostic devices, including B-mode imaging. This effect was purely mechanical, having been found in the absence of ultrasonic heating (see Sections 3.3 and 4.2).