High Energy Transmit Features
Verasonics’ “Extended Transmit Option” (also called “extended burst” or “push”) provides an internal power supply with up to 48 Watt capacity to sustain extended transmit bursts. A large energy storage capacitor provided within the system enables very high energy bursts, provided that enough time is allowed between transmissions to recharge the capacitor from the internal supply. This mode can damage transducers due to overheating, and can raise tissue temperatures above FDA safety limits. The Extended Transmit Option is available on all Vantage models except the Vantage 64.
The Verasonics Vantage research system, when configured to support HIFU or other high power transmit applications, can provide continuous output power levels of 8 Watts per channel into 50 Ohms (16 W into 100 Ohms) at transmit frequencies in the range from 1 to 5 MHz. The total system power output depends on other limits, such as the 1200 W capacity of the standard external power supply included with the HIFU configuration.
With the “HIFU Configuration”, circuit board provisions for additional thermal dissipation and connection of an external transmit power supply are added, and continuous transmit output power levels of up to 1000 Watts (2000 W with 2400 W supply) can be supported for a wide range of burst durations and repetition intervals, at any frequency in the 1 to 5 MHz range. Outside the fully supported frequency band, HIFU operation is possible but with reduced performance. The HIFU configuration permits all forms of imaging supported by the standard system using conventional imaging arrays, including radiation force methods. The HIFU Configuration (with external power supply) is available on both the Vantage 256 and the Vantage 128 models.
Automatic Limit Checking: Operating states destructive to the system can be programmed by the user given the very high transmit energy levels available with the extended transmit option. An automatic operating limit-checking algorithm is included with the system that prevents system operation at potentially damaging levels, overriding the user’s program. This limit test function can be extended by the user to protect the transducer from damage, or to impose acoustic output power limits during imaging or therapy events.