In situ exposimetry: the ovarian ultrasound examination

We have constructed a specialized in vivo exposimetry system and developed and tested customized software using specially fabricated hydrophones. We placed the hydrophones in the lateral vaginal fornix as close to the ovary as possible (usually 1-2 cm from the ovary) and determined selected first-order and second-order ultrasonic field quantities during a routine ultrasound examination of the ovary. Our sonographic measurements yielded mean ultrasound beam path distances of 7.6 cm. (n = 18) in the presence of a distended bladder and 7.0 cm. (n = 25) in the presence of an empty bladder with an average group insertion loss of 6.2 dB and 7.3 dB, respectively. Using a Fixed Attenuation Model, the tissue attenuation coefficient value was 2.98 dB/MHz; whereas for the Overlying Tissue Model the value was 0.72 dB/cm-MHz. These data are both specific and unique in that they have been systematically obtained in situ.