@jeffmarc
I think SBRT is x-rays, though they're different x-rays from the ones used for imaging.

From Google AI:
Stereotactic Body Radiotherapy (SBRT), also known as Stereotactic Ablative Radiotherapy (SABR), is a noninvasive, external beam photon radiation therapy that delivers highly precise, high-dose radiation to small, localized tumors in 5 or fewer sessions. It uses advanced imaging to target cancer while sparing surrounding healthy tissue.
Mayo Clinic
+4
Key Aspects of SBRT Treatment:
Radiation Type: Primarily uses high-energy X-ray beams (photons) generated by a Linear Accelerator (LINAC) or specialized systems like CyberKnife.
Technique: Delivers extremely accurate, high-dose "fractions" or treatments (often 1–5 sessions) compared to conventional radiation (many weeks).
Types of Machines: Common machines include CyberKnife, TrueBeam, Novalis, and VersaHD.
Common Targets: Used for tumors in the lung, liver, prostate, pancreas, spine, and kidney.
Goal: Ablate (destroy) the tumor, often acting as a noninvasive alternative to surgery for inoperable cases.