# K252977: Halcyon, Ethos Radiotherapy System (5.0)

- Pathway: 510(k) (Traditional)
- Applicant: Varian Medical Systems, Inc.
- Decided: Jan 21, 2026 after 126 days
- Product code: IYE (Accelerator, Linear, Medical)
- Device class: 2
- Regulation: 21 CFR 892.5050
- Recalls of this device: none
- Data: FDA decisions to Oct 25, 2026; recalls to Oct 12, 2026

## Lineage
Longest line of descent: 18 generations back to K010975 (2001). 64 ancestors in all.
1 later device descends from it; 1 cites it directly.
0 of 66 devices in its family (counting itself) have a Class I recall.

## Predicates on the family tree (from the FDA summary)
- K232113: Halcyon, Ethos Radiotherapy System, Varian Medical Systems, Inc. (2023) Summary page 5.

## Most influential descendants
- K261856: Halcyon, Ethos Radiotherapy System (5.0) (2026), 0 descendants of its own

## Indications for use
Halcyon and Ethos radiotherapy system are indicated for the delivery of stereotactic radiosurgery and precision radiotherapy for lesions, tumors, and conditions anywhere in the body where radiation is indicated for adults and pediatric patients. Halcyon and Ethos radiotherapy system with the HyperSight imaging feature produce kV CBCT anatomical images that can be used in the simulation and planning of radiation therapy.

Source page: https://510kreport.com/device/K252977
Methodology: https://510kreport.com/methodology