Abstract: A medical apparatus including an ultrasound transmitter and receiver system for acquiring ultrasound data descriptive of the speed of ultrasound along at least two paths. The medical apparatus further includes a medical imaging system for acquiring medical image data and a memory containing instructions that causes the processor to acquire the medical image data. The instructions further cause the processor to acquire the ultrasound data. The instructions further cause the processor to segment the medical image data into at least two tissue types. The instructions further causes the processor to determine at least two distances corresponding to the at least two paths in the subject. The instructions further cause the processor to calculate the speed of ultrasound in the at least two tissue types.

Abstract: The invention provides for a medical instrument (300, 500, 600) comprising a high intensity focused ultrasound system (302) comprising an ultrasonic transducer (306) with multiple transducer elements (400, 402, 404, 406, 408). The medical instrument further comprises a memory (334) containing machine executable instructions (350, 352, 354, 520, 522, 524) which cause a processor to receive (100, 200) a treatment plan (340) specifying a protected zone (322) within a subject (301) and to calculate (102, 208) a set of transducer control parameters (342) using the treatment plan. The set of transducer control parameters specify the switching of electrical power to the multiple transducer elements. An ultrasonic intensity estimate (900) in the protected zone is below a predetermined threshold. The ultrasonic intensity estimate is calculated using an incoherent sum of the ultrasonic pressure generated by each of the multiple transducer elements.

Abstract: A medical apparatus (400) comprising an ultrasound transmitter (444, 602) and receiver (446, 604) system (600) for acquiring ultrasound data (476) descriptive of the speed of ultrasound (304, 306) along at least two paths (606, 1114). The medical apparatus further comprises a medical imaging system (402) for acquiring medical image data (468) and a memory (464) containing instructions (490, 492, 494, 496, 498, 500, 502, 504) that causes the processor to acquire (100, 200) the medical image data. The instructions further cause the processor to acquire (102, 202) the ultrasound data. The instructions further cause the processor to segment (104, 204) the medical image data into at least two tissue types (434, 436, 610, 612, 708, 710). The instructions further causes the processor to determine (106, 206) at least two distances corresponding to the at least two paths in the subject. The instructions further cause the processor to calculate (108, 208) the speed of ultrasound in the at least two tissue types.