TABLE 1.

Comparison of SRS, LITT, extracorporeal HIFU, and interstitial HIFU

Feature	SRS	LITT	Extracorporeal HIFU	Interstitial HIFU
Technology	Delivers targeted radiation using multiple nonparallel beams. Where beams overlap is where the greatest amount of radiation occurs.	Light absorption causes the release of thermal energy to ablate targeted tissue.	Thermal ablation w/ sequential coagulation of small overlapping volumes w/ multiple, individual, short-time, high-power sonications delivered outside of the body.	Thermal ablation targeted therapy that can be delivered interstitially. Applicators are encased to protect surrounding tissue from thermal effects.
Uses	Gold standard for brain tumor treatment currently in conjunction w/ resection & chemotherapy.	Currently used as a surgical option in essential tremor & epilepsy.	Useful for very small malignant lesions.	Tailors more conformal heating patterns. Allows for precise margins regardless of tumor shape, location, & proximity to blood vessels.
Benefits	Targeted approach for large, irregularly shaped tumors near critical anatomical structures.	Minimally invasive. Reduced healing time.	Noninvasive.	Allows for the possibility of concurrent biopsy, as well as treatment during the same procedure. Offers increased thermal penetration into target volume.
Areas of improvement	No biopsy. Conformal patterns for all tumor shapes may be difficult.	May not be used around blood vessels or large hemorrhages. Charring with laser. Invasive.	Treatment may be limited due to patient motion & near-field heating. Treatment can last several hrs. Cannot be used near the skull.	Invasive therapy.