Abstract
The new 7.5MHz 3D ultrasonic probe developed for increasing the penetration depth of ultrasound. Specifications except frequency of the new probe are the same as those of 3D ultrasonic probes currently employed in clinical use.
Sonoscaning, using 3D ultrasonic probe (the new 7.5MHz probe and 3D-2R ; 12MHz, Olympus Optical Co.) was performed to a silicon board (a thickness of 1 mm) and a sponge phantom experimentally. The axial resolution of the both probes was enough to demonstrate the silicon board as an ultrasonic image consisting of 3 layers. In visualization of the sponge phantom, the penetration depth of the new 7.5MHz probe was extended for 5 mm in comparison with that of 3D-2R. In clinical study, endoscopic ultrasonography (EUS) by the new 7.5MHz probe was performed in 19 patients (gastric cancer : 2, colorectal cancer : 10, colorectal submucosal tumor : 5, others : 2) . The mean depth of penetration was around 24.9 mm in the ultrasonic images. In 14 of these patients, EUS by 3D-2R was also performed to the same part of each lesion. The mean depth of penetration of the new 7.5MHz probe was around 23.0 mm, and was extended for 6 mm in comparison with that of 3D-2R.
The newly developed 7.5MHz 3D ultrasonic probe was considered to have the visibility of extraluminal components as lymph nodes. However, the penetration depth and stability of ultrasound should be improved to make this probe a valuable diagnostic device.
