Different types of Probes / transducers Curvilinear probe Linear probe Endocavitary probe - 3-5 MHz (Low frequency) - Greater wavelength - Greater penetration - Poor resolution -Used for imaging deep structures e.g. kidney, ovary, fetal pas etc. - 10-12 MHz (high frequency) -Low wavelength - Poor penetration - Good resolution - Used for superficial structures e.g. thyroid, breast, scrotum etc. - 7- 10 MHz (Good frequency) - TVS (Transvaginalsonography) - TRUS (Transrectalultrasound) - TEE (Trans esophagealechocardiography) TVS (Trans vaginal sonography) IOC for Ectopic pregnancy Bladder must be empty before doing TVS - Endoscopic Ultrasound (EUS) Uses frequency of 20 MHZ Very good resolution Divides gut wall into 5 layers EUS is the IOC for local invasion or T staging of early esophageal cancer (IOC for Advanced esophageal Carcinoma - CECT)