MAUDE Adverse Event Report: ELEKTA SOLUTIONS AB MOSAIQ; ACCELERATOR, LINEAR, MEDICAL

Lot Number	VERSION 2.86.077
Medical Device Problem Code	Computer Software Problem (1112)
Health Effect - Clinical Code	Insufficient Information (4580)
Date of Event	06/10/2025
Type of Reportable Event	Serious Injury
Event or Problem Description
The customer reported that the patient was treated with an incorrect isocenter in the y-direction.
Additional Manufacturer Narrative
H4: manufacturing date is not on the label, but it is known so field h4 has been completed with this information.The manufacturer's investigation is on-going and further information will be provided once the investigation has completed.
Additional Manufacturer Narrative
H2 updated, h6 updated, h11 updated.The investigation was completed by conducting a thorough evaluation of the product and the reported information.The customer reported that the patient was treated with an incorrect isocenter in the y-direction.In-house testing was performed using the provided treatment plan, computerised tomography (ct) scan, and structure set (ss) which were imported into mosaiq.The imported isocenter values matched the expected co-ordinates in the reference structure set/isocenter of site setup.Based on the treatment event data, it appears that site setup was created manually by a user and no isocenter values were entered.A plan for the patient was later imported by another user.The pre-existing site setup was edited with x:0, y: 3, z: -8 isocenter values.The entry of y: 3 instead of y: -3 for the isocenter is due to use error.The patient received treatment using the incorrect isocenter (y: 3) for all five fractions.Elekta physics have assessed this as a serious radiation overdose.Mosaiq did not have any malfunction and was working as designed and intended.The findings of our investigation have been formally communicated to the customer via email.

• Brand Name: MOSAIQ
• Common Device Name: ACCELERATOR, LINEAR, MEDICAL
• Manufacturer (Section D): ELEKTA SOLUTIONS AB; hagaplan 4; stockholm, SE-11 3 68; SW SE-113 68
• Manufacturer (Section G): ELEKTA SOLUTIONS AB; 400 perimeter center terrace; suite 50; atlanta GA 30346
• Manufacturer Contact: cornerstone; london road; crawley, west sussex RH10 -9BL
• MDR Report Key: 22607379
• Report Number: 3015232217-2025-00047
• Device Sequence Number: 5457407
• Product Code: IYE
• UDI-Device Identifier: 00858164002367
• UDI-Public: (01)00858164002367(10)2.86.077
• Combination Product (Y/N): N
• Initial Reporter State: WA
• Initial Reporter Country: US
• PMA/510(K) Number: K183034
• Number of Events Summarized: 1
• Summary Report (Y/N): N
• Serviced by Third Party (Y/N): Unknown
• Reporter Type: Manufacturer
• Report Source: Other,Health Professional,User Facility
• Initial Reporter Occupation: Other Health Care Professional
• Type of Report: Initial,Followup
• Report Date (Section B): 09/10/2025

1 Device was Involved in the Event

1 Patient was Involved in the Event

• Is this an Adverse Event Report?: Yes
• Is this a Product Problem Report?: No
• Operator of Device: Health Professional
• Device Lot Number: VERSION 2.86.077
• Was Device Available for Evaluation?: Yes
• Is the Reporter a Health Professional?: Yes
• Type of Report(Section G): Thirty-Day
• Initial Date Received by Manufacturer: 06/25/2025
• Supplement Date Received by Manufacturer: Not provided
• Initial Report FDA Received Date: 07/25/2025
• Supplement Report FDA Received Date: 09/10/2025
• Was Device Evaluated by Manufacturer? (Y/N): Yes
• Date Device Manufactured: 12/18/2023
• Is the Device Labeled for Single Use? (Y/N): No
• Is This a Single-Use Device that was Reprocessed and Reused on a Patient? (Y/N): No
• Usage of Device: Reuse
• Patient Sequence Number: 1
• Outcome Attributed to Adverse Event: Other
• Patient Sex: Unknown