Lower riskMedical device recall · FDA · Published September 4, 2019
Elekta Monaco RTP System 5.50/5.51: Incorrect Dose Calculation Risk
Elekta recalls Monaco RTP System software versions 5.50 and 5.51 due to potential incorrect radiation dose calculations, which could affect cancer treatment safety. Affected users should contact Elekta for details.
It is possible that the forced electron density settings will be changed for some structures unintentionally and this can result in incorrect dose calculation.
Take action
Contact the company
📍Recalling firmElekta Inc13723 Riverport Dr Ste 100 · Maryland Heights, MO 63043-4819
✎ GovInfoNow plain-language explainer
Elekta is recalling two software versions of its Monaco radiation treatment planning system because changes to electron density settings might cause incorrect dose calculations. This could lead to unsafe radiation treatment plans for cancer patients. Read more at govinfonow.com/recall/67071-elekta-monaco-rtp-system-5-50-5-51-incorrect-dose.
“Elekta Monaco RTP System 5.50/5.51: Incorrect Dose Calculation Risk.” GovInfoNow, updated August 19, 2026. https://govinfonow.com/recall/67071-elekta-monaco-rtp-system-5-50-5-51-incorrect-dose. Based on FDA recall #Z-2561-2019 (https://api.fda.gov/device/enforcement.json?search=recall_number:%22Z-2561-2019%22&limit=1).
The FDA announced on 2019-09-04 that Elekta, Inc. is voluntarily recalling the Monaco RTP System, versions 5.50 and 5.51, because forced electron density settings may change unintentionally, leading to incorrect dose calculations. The agency issued recall number Z-2561-2019 for the radiation treatment planning devices.
How to tell if you have it
Elekta Monaco RTP System, versions 5.50 and 5.51
UPC 00858164002244 (version 5.50)
UPC 00858164002268 (version 5.51)
The hazard
According to the FDA, the hazard is that forced electron density settings may be changed for some structures unintentionally, which can result in incorrect dose calculation.
Context
GovInfoNow's records show Elekta, Inc. has 39 other recalls on record since 2017-06-19. Recent Elekta recalls include the 2026-05-21 MOSAIQ Oncology System Software Recall for treatment plan loading risk, the 2026-04-03 Advanced Gynecological Applicator Recall for IU tube detachment risk, and the 2026-03-19 Leksell Vantage Arc System Recall for shifting coordinates risk. Other recent recalls of similar products include RayStation/RayPlan Software 11A Recalls (2025-11-28), RayStation Software Version 15.2.0/15.1.3 (2025-11-28), and RayStation/RayPlan 10B Software Recall (2025-11-28).
How to tell if you have this one
Check if you have the Monaco RTP System software versions 5.50 or 5.51. The system is used for radiation treatment planning in cancer care and has a unique identifier (UDI) starting with (01)00858164002244(10) for version 5.50.00.
FDA lists each product line separately under one recall event. Check your product description, lot or code numbers against each row. Every row shares the hazard and remedy on this page.
Classification
Class II
Status
Ongoing
Distribution
Worldwide Distribution - US Nationwide in the states of WI, OH, NY, OH, IN, IA, TX, and countries of Canada, China, Denmark, Germany, Greece, Hong Kong, Italy, Netherlands, Sweden, UK
Recall number
Product, codes & lots
Quantity
Z-2560-2019
Monaco RTP System, 5.40 Unity, radiation treatment planning system Product Usage: The Monaco system is used to make treatment plans for patients with prescriptions for external beam radiation therapy. The system calculates dose for photon, electron, and carbon treatment plans and displays, on-screen and in hard-copy, two- or three-dimensional radiation dose distributions inside patients for given treatment plan set-ups. The Monaco product line is intended for use in radiation treatment planning. It uses generally accepted methods for: -contouring -image manipulation -simulation -image fusion -plan optimization -QA and plan review; UDI (01)00858164002190(10) 5.40.00
30 units
Z-2561-2019
Monaco RTP System, 5.50/5.51, radiation treatment planning system Product Usage: The Monaco system is used to make treatment plans for patients with prescriptions for external beam radiation therapy. The system calculates dose for photon, electron, and carbon treatment plans and displays, on-screen and in hard-copy, two- or three-dimensional radiation dose distributions inside patients for given treatment plan set-ups. The Monaco product line is intended for use in radiation treatment planning. It uses generally accepted methods for: -contouring -image manipulation -simulation -image fusion -plan optimization -QA and plan review; UDI: (01)00858164002244(10) 5.50.00 (01)00858164002268(10) 5.51.00
49 units
Based on the official FDA remedy
What to do — step by step
Contact Elekta
Reach out to Elekta for specific guidance on the recalled software versions and next steps.
Where it went and when
Where it was distributed
Distributed nationwide and abroad; the notice names 6 states.
Named in the notice
Covered by “nationwide”
Not listed
FDA distribution: “Worldwide Distribution - US Nationwide in the states of WI, OH, NY, OH, IN, IA, TX, and countries of Canada, China, Denmark, Germany, Greece, Hong Kong, Italy, Netherlands, Sweden, UK” States read from FDA’s own wording; “not listed” means the notice does not name it.
Named in the notice: Indiana, Iowa, New York, Ohio, Texas, Wisconsin.
Recall timeline
FDA published this recall 28 days after the firm started it.
1Firm started the recall
2FDA classified it Class II
3Published in FDA’s Enforcement Report
Dates from the agency record only; steps without a date are left out.
The recall is for potential incorrect dose calculations, which could affect cancer treatment safety. However, the hazard is not described as causing serious injury in normal use, so it's considered low risk.
The facts (hazard, remedy, dates, manufacturer) are pulled from the official FDA recall record. The plain-language summary and step-by-step checklist are written by GovInfoNow to make the official notice easier to act on — they don’t replace it.
Official source: FDA Recall #Z-2561-2019 (September 4, 2019) — FDA publishes no per-recall page; this is the official machine-readable enforcement record. Search FDA recalls for Z-2561-2019 to see it in context.
Plain-language summary written by qwen3:4b on August 19, 2026, from the official record above. Not reviewed by a person — if it conflicts with the FDA notice, the notice is correct. Report an error on this page.
GovInfoNow is an independent service and is not a government agency. We republish official FDA recall data; we don’t issue, amend or administer recalls.