Final answer:
The best ultrasound configuration for imaging deep tissues uses lower frequencies, usually within 0.8 to 1 MHz, which provide sufficient penetration without excessive tissue absorption. Advanced imaging techniques involve constructing images from phased ultrasound sources, and the use of a coupling gel enhances sound wave transmission from the transducer into the body.
Step-by-step explanation:
To image deep tissues, the best ultrasound configuration would use lower frequencies, typically within the range of 0.8 to 1 MHz. The use of lower frequencies is pivotal because higher-frequency ultrasound, while providing greater detail, does not penetrate as deeply due to attenuation. A general rule indicates that ultrasound can effectively scan to a depth of about 500 times the wavelength of the ultrasound in the tissue. For a frequency of 7 MHz, this penetration limit is 500×0.22 mm, which is 0.11 m. In contrast, lower frequencies such as those around 1 MHz are utilized in ultrasound diathermy for deep-heat treatments to relieve pain and improve flexibility in muscles, where it is essential to avoid potential tissue damage including "bone burns" and cavitation.
During ultrasonography, the device broadcasts a directional beam, sweeping across the area of interest. This is accomplished by multiple ultrasound sources within the probe's head that are phased to interfere constructively. The computer then constructs an image that reveals the shape and density of internal structures. Furthermore, ultrasound transducers are always coupled to the skin with a layer of gel to optimize the transmission of sound waves into the body, minimizing reflection and ensuring better image quality.