510(k) Report

510(k) · Cleared

Cleared

Halcyon, Ethos Radiotherapy System (5.0)

K252977510(k) TraditionalCleared Jan 21, 2026126-day reviewClass II21 CFR 892.5050

Data to Oct 25, 2026 (FDA decisions) Oct 12, 2026 (recalls) Sep 30, 2026 (MAUDE) refreshed weekly, last Nov 3, 2026

Varian Medical Systems, Inc. · IYE Accelerator, Linear, Medical

Cleared on Jan 21, 2026 as substantially equivalent to K232113 (Varian Medical Systems, Inc., 2023) after a 126-day review. Its family tree reaches back 18 generations to 2001. 1 later device descends from it.

Decided
Jan 21, 2026
Review
126 days
Class
Class II
Product code
IYE
Recalls
None
Predicates
1

Its longest line of descent runs back 18 generations to K010975 (2001). 64 ancestors in all, the oldest K864886 (1987). 1 later device descends from it, 1 citing it directly.

Other ancestors, by year clearedDescendants, by year cleared 2018: 2 other ancestors2017: 2 other ancestors2014: 3 other ancestors2009: 2 other ancestors2005: 3 other ancestors2000: 5 other ancestors1995: 2 other ancestors2013: 1 other ancestor2012: 2 other ancestors2010: 1 other ancestor2011: 1 other ancestor1999: 2 other ancestors2008: 2 other ancestors1987: 1 other ancestor2007: 3 other ancestors2006: 2 other ancestors2004: 3 other ancestors2001: 1 other ancestor1996: 2 other ancestors2003: 2 other ancestors1997: 2 other ancestors2002: 1 other ancestor1991: 1 other ancestor2026: 1 descendant clearedK010975 · Eclipse 6.5 · Varian Medical Systems, Inc. · 2001 · recalledK030981 · Eclipse · Varian Medical Systems, Inc. · 2003K041403 · Eclipse with Aaa · Varian Medical Systems · 2004K050296 · Eclipse Treatment Planning System · Varian Medical Systems · 2005×2: 2 generations cleared close together, K071873 (2007), K073020 (2007) K091492 · Modification to Eclipse Treatment Planning System · Varian Medical Systems, Inc. · 2009 · recalledK102011 · Eclipse Treatment Planning System · Varian Medical Systems, Inc. · 2010 · recalled×2: 2 generations cleared close together, K131891 (2013), K133247 (2014) K141283 · Eclipse Treatment Planning System · Varian Medical Systems, Inc. · 2014 · recalledK152393 · Eclipse Treatment Planning System · Varian Medical Systems, Inc. · 2015 · recalled×2: 2 generations cleared close together, K170969 (2017), K172163 (2017) K181145 · Eclipse Treatment Planning System · Varian Medical Systems, Inc. · 2018 · recalledK192377 · Ethos Treatment Management, Ethos Treatment Planning, Ethos Radiotherapy System, Halcyon · Varian Medical Systems, Inc. · 2020K222941 · Halcyon, Ethos Radiotherapy System · Varian Medical Systems, Inc. · 2023K232113 · Halcyon, Ethos Radiotherapy System · Varian Medical Systems, Inc. · 20231990200020102020
Other ancestors, by generationDescendants, by generation 4 generations back: 2 other ancestors5 generations back: 2 other ancestors6 generations back: 2 other ancestors7 generations back: 2 other ancestors8 generations back: 3 other ancestors9 generations back: 3 other ancestors10 generations back: 3 other ancestors11 generations back: 3 other ancestors12 generations back: 8 other ancestors13 generations back: 4 other ancestors14 generations back: 4 other ancestors15 generations back: 9 other ancestors16 generations back: 1 other ancestor 1 generation forward: 1 descendant K232113 · Halcyon, Ethos Radiotherapy System · Varian Medical Systems, Inc. · 2023K222941 · Halcyon, Ethos Radiotherapy System · Varian Medical Systems, Inc. · 2023K192377 · Ethos Treatment Management, Ethos Treatment Planning, Ethos Radiotherapy System, Halcyon · Varian Medical Systems, Inc. · 2020K181145 · Eclipse Treatment Planning System · Varian Medical Systems, Inc. · 2018 · recalledK172163 · Eclipse Treatment Planning System · Varian Medical Systems, Inc. · 2017 · recalledK170969 · Eclipse Treatment Planning System · Varian Medical Systems, Inc. · 2017 · recalledK152393 · Eclipse Treatment Planning System · Varian Medical Systems, Inc. · 2015 · recalledK141283 · Eclipse Treatment Planning System · Varian Medical Systems, Inc. · 2014 · recalledK133247 · Eclipse Treatment Planning System · Varian Medical Systems, Inc. · 2014K131891 · Eclipse Treatment Planning System · Varian Medical Systems, Inc. · 2013K102011 · Eclipse Treatment Planning System · Varian Medical Systems, Inc. · 2010 · recalledK091492 · Modification to Eclipse Treatment Planning System · Varian Medical Systems, Inc. · 2009 · recalledK073020 · Eclipse Treatment Planning System · Varian Medical Systems, Inc. · 2007 · recalledK071873 · Modification to Eclipse Treatment Planning System · Varian Medical Systems, Inc. · 2007 · recalledK050296 · Eclipse Treatment Planning System · Varian Medical Systems · 2005K041403 · Eclipse with Aaa · Varian Medical Systems · 2004K030981 · Eclipse · Varian Medical Systems, Inc. · 2003K010975 · Eclipse 6.5 · Varian Medical Systems, Inc. · 2001 · recalled−15−10−50
  1. Root · 18 generations backK010975 Eclipse 6.5Varian Medical Systems, Inc. · 2001 · Recalled
  2. 14 generations between
  3. 3 generations backK192377 Ethos Treatment Management, Ethos Treatment Planning, Ethos…Varian Medical Systems, Inc. · 2020
  4. 2 generations backK222941 Halcyon, Ethos Radiotherapy SystemVarian Medical Systems, Inc. · 2023
  5. 1 generation backK232113 Halcyon, Ethos Radiotherapy SystemVarian Medical Systems, Inc. · 2023
  6. This deviceK252977 Halcyon, Ethos Radiotherapy System (5.0)Varian Medical Systems, Inc. · 2026
  7. Descendant · cites it directly · 0 of its ownK261856 Halcyon, Ethos Radiotherapy System (5.0)Varian Medical Systems, Inc. · 2026
Show all 18 generations
  1. Root · 18 generations backK010975 Eclipse 6.5Varian Medical Systems, Inc. · 2001 · Recalled
  2. 17 generations backK030981 EclipseVarian Medical Systems, Inc. · 2003
  3. 16 generations backK041403 Eclipse with AaaVarian Medical Systems · 2004
  4. 15 generations backK050296 Eclipse Treatment Planning SystemVarian Medical Systems · 2005
  5. 14 generations backK071873 Modification to Eclipse Treatment Planning SystemVarian Medical Systems, Inc. · 2007 · Recalled
  6. 13 generations backK073020 Eclipse Treatment Planning SystemVarian Medical Systems, Inc. · 2007 · Recalled
  7. 12 generations backK091492 Modification to Eclipse Treatment Planning SystemVarian Medical Systems, Inc. · 2009 · Recalled
  8. 11 generations backK102011 Eclipse Treatment Planning SystemVarian Medical Systems, Inc. · 2010 · Recalled
  9. 10 generations backK131891 Eclipse Treatment Planning SystemVarian Medical Systems, Inc. · 2013
  10. 9 generations backK133247 Eclipse Treatment Planning SystemVarian Medical Systems, Inc. · 2014
  11. 8 generations backK141283 Eclipse Treatment Planning SystemVarian Medical Systems, Inc. · 2014 · Recalled
  12. 7 generations backK152393 Eclipse Treatment Planning SystemVarian Medical Systems, Inc. · 2015 · Recalled
  13. 6 generations backK170969 Eclipse Treatment Planning SystemVarian Medical Systems, Inc. · 2017 · Recalled
  14. 5 generations backK172163 Eclipse Treatment Planning SystemVarian Medical Systems, Inc. · 2017 · Recalled
  15. 4 generations backK181145 Eclipse Treatment Planning SystemVarian Medical Systems, Inc. · 2018 · Recalled
  16. 3 generations backK192377 Ethos Treatment Management, Ethos Treatment Planning, Ethos…Varian Medical Systems, Inc. · 2020
  17. 2 generations backK222941 Halcyon, Ethos Radiotherapy SystemVarian Medical Systems, Inc. · 2023
  18. 1 generation backK232113 Halcyon, Ethos Radiotherapy SystemVarian Medical Systems, Inc. · 2023
  19. This deviceK252977 Halcyon, Ethos Radiotherapy System (5.0)Varian Medical Systems, Inc. · 2026

Most influential descendants

Showing 1 of 1 · See all
  • K261856Halcyon, Ethos Radiotherapy System (5.0)Varian Medical Systems, Inc. · 2026 · cites it directly0descendants
View FIG. 1 as a table

Line of descent and top descendants

GenerationNumberDeviceApplicantDecidedRecalls
−18K010975Eclipse 6.5Varian Medical Systems, Inc.20013
−17K030981EclipseVarian Medical Systems, Inc.2003—
−16K041403Eclipse with AaaVarian Medical Systems2004—
−15K050296Eclipse Treatment Planning SystemVarian Medical Systems2005—
−14K071873Modification to Eclipse Treatment Planning SystemVarian Medical Systems, Inc.20075
−13K073020Eclipse Treatment Planning SystemVarian Medical Systems, Inc.20076
−12K091492Modification to Eclipse Treatment Planning SystemVarian Medical Systems, Inc.20092
−11K102011Eclipse Treatment Planning SystemVarian Medical Systems, Inc.20105
−10K131891Eclipse Treatment Planning SystemVarian Medical Systems, Inc.2013—
−9K133247Eclipse Treatment Planning SystemVarian Medical Systems, Inc.2014—
−8K141283Eclipse Treatment Planning SystemVarian Medical Systems, Inc.20141
−7K152393Eclipse Treatment Planning SystemVarian Medical Systems, Inc.20151
−6K170969Eclipse Treatment Planning SystemVarian Medical Systems, Inc.20171
−5K172163Eclipse Treatment Planning SystemVarian Medical Systems, Inc.20171
−4K181145Eclipse Treatment Planning SystemVarian Medical Systems, Inc.20181
−3K192377Ethos Treatment Management, Ethos Treatment Planning, Ethos Radiotherapy…Varian Medical Systems, Inc.2020—
−2K222941Halcyon, Ethos Radiotherapy SystemVarian Medical Systems, Inc.2023—
−1K232113Halcyon, Ethos Radiotherapy SystemVarian Medical Systems, Inc.2023—
0 (this device)K252977Halcyon, Ethos Radiotherapy System (5.0)Varian Medical Systems, Inc.2026—
+1K261856Halcyon, Ethos Radiotherapy System (5.0)Varian Medical Systems, Inc.2026—

Other ancestors by year cleared

Year clearedDevicesWith a Class I recall
198710
199110
199520
199620
199720
199920
200050
200110
200210
200320
200430
200530
200620
200730
200820
200920
201010
201110
201220
201310
201430
201720
201820

Descendants by year cleared

Year clearedDevicesWith a Class I recall
202610
FIG. 1 — Lineage of K252977, 2001–2026Source: FDA 510(k) summaries, read by 510(k) Report · How lineage is built

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Notable FDA decisions, review times and new Class I recalls. See an issue.

Sources: FDA 510(k) database (decision fields), the FDA summary (predicates and indications), FDA recall and enforcement reports, and MAUDE; processed by 510(k) Report. Verify on FDA.gov · Methodology and accuracy.

Planning a device in IYE? A 510(k) Report weighs predicate choices, recall history and review times for a new device like this one.

Top candidate predicates for a new IYE device

  1. #1 K261856 Halcyon, Ethos Radiotherapy System (5.0)score 17.2 · 19 generations · no Class I recall
  2. #2 Held for the reportin the report
  3. #3 Held for the reportin the report
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What was it cleared against? (1)

Devices the submitter claimed this one is substantially equivalent to (*), and reference devices cited for a specific test or feature (†), as written in the FDA summary.

TypeNumberDeviceApplicantDecidedRecalls
*K232113Halcyon, Ethos Radiotherapy System
Summary page 5
…21CFR892.5050, IYE, Class II Common/Usual Name: Medical Linear Accelerator Predicate Devices: Halcyon, Ethos Radiotherapy System (K232113). Device Description: Halcyon and Ethos Radiotherapy System are single energy medical linear…
Varian Medical Systems, Inc.2023—

What descends from it? (1)

1 later device cites it directly; ranked here by how many devices descend from each in turn.

NumberDeviceApplicantDecidedDescendants
K261856Halcyon, Ethos Radiotherapy System (5.0)Varian Medical Systems, Inc.20260

Has anything in its family been recalled? (0 Class I)

No FDA recall names this device.

No ancestor or descendant has a Class I recall.

What does this lineage say?

  • The line of descent spans 25 years and passes through 2 companies; a new generation was cleared every 1.3 years on median.
  • 40 of the 64 ancestors have a recall of any class.
  • Of its descendants, K261856 (Varian Medical Systems, Inc., 2026) has gone furthest, with 0 descendants of its own.

How does its category compare?

All IYE devices

IYE Accelerator, Linear, Medical: FDA decisions, review times, recalls and adverse event reports over 20 years. 2026, this device’s year, is highlighted.

FDA decisions per year · IYE

12in 2025

2007: 232008: 142009: 202010: 232011: 112012: 282013: 182014: 202015: 202016: 212017: 232018: 212019: 192020: 202021: 192022: 122023: 182024: 92025: 122026 (partial year): 14
2007high 28 (2012) · low 9 (2024)2026

2026 to Oct 25, outlined.

Median 510(k) review, days · IYE

170in 2025

2007: 44 days median2008: 69 days median2009: 63 days median2010: 74 days median2011: 94 days median2012: 106 days median2013: 88 days median2014: 100 days median2015: 108 days median2016: 97 days median2017: 94 days median2018: 58 days median2019: 83 days median2020: 67 days median2021: 86 days median2022: 172 days median2023: 129 days median2024: 239 days median2025: 170 days median2026 (partial year): 120 days median
2007high 239 (2024) · low 44 (2007)2026

Receipt to decision; years with fewer than 3 clearances left blank.

Recalls per year · IYE

1in 2025

2007: 782008: 492009: 222010: 272011: 732012: 202013: 112014: 142015: 82016: 72017: 72018: 72019: 22020: 42021: 52022: 32023: 72024: 12025: 12026 (partial year): 4
2007high 78 (2007) · low 1 (2024)2026

Class I (0 since 2007) Class II/III not classified

Adverse event reports per year · IYE

101in 2025

2007: 1552008: 1142009: 1742010: 2462011: 2802012: 1282013: 962014: 1242015: 1002016: 972017: 1252018: 852019: 912020: 742021: 682022: 662023: 1282024: 812025: 101
2007high 280 (2011) · low 66 (2022)2025

MAUDE reports naming product code IYE, not matched to any one device; reports are not rates.

View these four charts as a table
YearDecisionsMedian 510(k) review, daysRecalls (Class I)MAUDE reports
2007234478155
2008146949114
2009206322174
2010237427246
2011119473280
20122810620128
201318881196
20142010014124
2015201088100
20162197797
201723947125
20182158785
20191983291
20202067474
20211986568
202212172366
2023181297128
20249239181
2025121701101
2026141204—

What is it indicated for?

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.

Indications for use read by OCR from a scanned FDA summary, so letters may be misread. Check the PDF before quoting it.

Cite this page

510(k) Report. “K252977: Halcyon, Ethos Radiotherapy System (5.0).” Lineage record from FDA 510(k) data and the FDA summary. Updated Nov 3, 2026. Accessed Nov 4, 2026. https://510kreport.com/device/K252977

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Record history
  • FDA decision record loaded May 2, 2026
  • Summary read Oct 13, 2026 (extraction version 9eaa42aa01ed)
  • Lineage and recalls computed Nov 3, 2026
  • Page last updated Nov 3, 2026