The frame rate is the number of images displayed per second. One frame represents one complete sweep of the ultrasound beam and contains many pulse-listen cycles. The frame rates decrease with an increased dwell time.

Handheld ultrasound systems are portable devices for smartphone or tablet and are increasingly common in emergency, intensive care and veterinary medicine, but also in the pocket of the stationary doctor. This type of ultrasound machine enables immediate diagnoses directly on site (handheld point-of-care-ultrasound / HPOCUS) and quickly provide information regarding the patient's further care. Handheld ultrasound machines fit into a single-use plastic cover and can be easily disinfected, making them particularly useful in infectious environments.
The most striking advantage of handheld POCUS devices is the small footprint. The design is very compact, lightweight (approx. 200 g/0,44 lbs. - 500 g/1,1 lbs) and flexible. Due to this compactness and the necessary technical compression, the quality of the imaging is still limited compared to 'high-end devices', but sufficient to the extent that handheld ultrasound devices are already successfully used in many medical disciplines.
Depending on the model, handheld ultrasound systems run on Android, iOS, Windows or proprietary operating systems. They are connected to the end device via USB cable or wirelessly via Bluetooth or WiFi. The respective end device is used as an ultrasound monitor to display the ultrasound images. The associated app is operated via touchscreen, although some devices have a few buttons, e.g. for recording ultrasound images or freeze images. The images can be stored and managed on the end device itself, the inserted memory card or in the cloud. Theoretically, also a private smartphone can be connected, but this can lead to complications with reimbursement.
See also Portable Ultrasound Machine, Ultrasound Technology, Environmental Protection, Ultrasound Accessories and Supplies and Sonographer.

From Hitachi Medical Corporation (HMC), sales, marketing and service in the US by Hitachi Medical Systems America Inc.
The HI VISION™ 5500 - EUB-5500 fully digital ultrasound system delivers the latest generation of signal processing technology, sophisticated transducer design, and a host of features and options for advanced imaging capabilities across a wide range of clinical situations. This system is compatible with all Pentax ultrasound endoscopes.

From Hitachi Medical Corporation (HMC), sales, marketing and service in the US by Hitachi Medical Systems America Inc.;
Powerful, flexible, and fast, the HI VISION™ 8500 - EUB-8500 diagnostic ultrasound scanner combines leading edge technologies with user-oriented operation for exceptional imaging and functionality.
Available exclusively on the 8500, SonoElastography provides a new perspective on the physical properties of tumors and masses by determining and displaying the relative stiffness of tissue.

From Hitachi Medical Corporation (HMC);
The HI VISION™ 6500 - EUB-6500 high resolution digital ultrasound system offers advanced clinical imaging, enhanced operating efficiency, and remarkable clinical flexibility, all in robust and versatile configuration that simply represents a better clinical solution in a variety of real-world, real-work arenas.