# K981055: Xknife-4

- Pathway: 510(k) (Traditional)
- Applicant: Radionics, Inc.
- Decided: Sep 29, 1998 after 190 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
No predicates in its family tree.
5 later devices descend from it; 2 cite it directly.
0 of 6 devices in its family (counting itself) have a Class I recall.

## Predicates on the family tree (from the FDA summary)
- None. The FDA summary names its predicate without a number.
- (no number) XKnife-3 System: named in the summary without a submission number
- (no number) XPlan-1 System: named in the summary without a submission number

## Most influential descendants
- K991237: Xplan-2 with Head and Neck Localizer, Model HNL (1999), 2 descendants of its own
- K081935: Stereotactic Head and Neck Localizer, Model 50-100 (2008), 1 descendant of its own
- K041997: Radionics Xknife RT 3 with Non Stereotactic Module (2004), 1 descendant of its own
- K103616: Pinpoint Stereotactic Head and Neck Localizer (2011), 0 descendants of its own
- K061893: Integra Radionics Xknife RT 4 (2006), 0 descendants of its own

## Indications for use
XKnife-4 is intended for use in stereotactic, collimated beam, computer planned, LINAC (linear accelerator) based radiosurgery and radiotherapy treatment.

Source page: https://510kreport.com/device/K981055
Methodology: https://510kreport.com/methodology