Читать книгу The Physics and Technology of Diagnostic Ultrasound: A Practitioner's Guide - Robert Gill - Страница 33

1 Consider a 10 MHz probe used for breast scanning. Suppose that it has a depth of penetration of 8 cm.Calculate the delay between the transmit pulse and the last detectable echo.Suppose that the machine requires 200 transmit pulses to create an image. Calculate how long it takes to create an image.Using the answer to (b), calculate the frame rate (i.e. how many images will be created each second).Check that (FR × P × N) = 77,000. Don't be concerned if you don't get exactly 77,000 – this will be due to rounding errors.

2 Note the actual frame rate at which a clinical ultrasound machine operates and whether the frame rate changes when you switch from a low frequency probe to a high frequency probe. Consider whether the differences that you observe are consistent with the above discussion.