Optimization of transcostal phased-array refocusing using iterative sparse semidefinite relaxation method

High Intensity Focused Ultrasound (RIFU) is a means of noninvasively treating cancer by focusing an array of ultrasound transducers onto a focal tumor. The use of large transducer arrays allows for a high focal power deposition, without necessitating undue heating in the intermediary tissue between the transducer array and the target. However, organs that are directly obscured by the ribs present a challenge for HIFU treatment. The ribs distort the ultrasound waves, while also absorbing their energy, causing them to heat and potentially burn the surrounding tissue. As a result of the ribs' presence, the effectiveness of HIFU treatments is limited.