GentleBeam (GB1000)

The GentleBeam is a mobile, low-energy x-ray radiation therapy system designed to treat skin cancers (basal cell carcinoma, squamous cell carcinoma, cutaneous appendage carcinoma, Kaposi's sarcoma) and keloids. It operates at 50kV, 70kV, and 100kV and includes an integrated laser-induced ultrasound imaging system (branded Photosonic) to visualize skin layers and measure lesion depth to assist in treatment planning.

The GentleBeam uses a transmission-type x-ray target on a diamond substrate (versus the predicate's reflective tungsten target), requiring lower tube current (2–3 mA versus 8–10 mA) to achieve similar dose rates of 500–1500 cGy/min. It employs a six-axis robotic arm with manual hand-guided operation to position the x-ray head, whereas the predicate uses a three-joint scissor arm. The imaging component is laser-induced ultrasound (LIUS) rather than conventional piezoelectric ultrasound, using photoacoustic effect and Fabry-Perot interferometry to generate volumetric 3D images.

IEC 60601-1 (general medical electrical equipment safety), IEC 60601-1-2 (EMC), IEC 60601-1-6 (usability), IEC 60601-2-8 (therapeutic x-ray equipment), IEC 60601-2-37 (ultrasound equipment), IEC 62304 (medical device software), IEC 62366-1 (usability engineering), and AAPM TG-61 (x-ray output physics verification). All testing was performed by accredited independent laboratories (TÜV Rheinland, Acertera).

GentleBeam is substantially equivalent to the predicate SRT-100 Vision because both share identical indications for use, employ x-ray photon therapy, use electron-cathode acceleration, produce spherical dose geometry, and achieve equivalent treatment times (~10–30 seconds versus 15–37 seconds for 250 cGy standard fractions). Design differences (transmission target, robotic arm, LIUS imaging) are minor industrial design improvements that do not raise new safety or effectiveness questions, and all performance testing demonstrates equivalent essential performance.