High intensity focused ultrasound: A noninvasive therapy for locally advanced pancreatic cancer

Table 3 Technical and therapeutic differences in continuous high intensity focused ultrasound and pulsed focused ultrasound therapy

	US wave	US intensity	Treatment session	Change in US image during procedure	Treatment mechanism	Treatment use	Required anesthesia	Appearances in follow-up images
Continuous HIFU therapy	Continuous	5-20kW/cm2	One session	Real-time hyperechoic change in the focus during each shot	Thermal ablation for coagulation necrosis	Monotherapy, used alone	Sedation or general anesthesia	No contrast enhancement in tumor on MRI/CT; negative uptake on PET/CT
Pulsed focused ultrasound therapy	Pulsed	< 3 kW/cm2	Multiple sessions	No real-time US image change during each shot	Hyperthermia for enhancing sensitive to chemotherapeutic agents	Need to be combined with chemotherapy	Sedation or none	Tumor shrinkage on MRI/CT; negative uptake on PET/CT

HIFU: High intensity focused ultrasound; US: Ultrasound.