MAUDE Adverse Event Report: VIEWRAY, INC. MRIDIAN LINAC; RADIATION THERAPY

Model Number 20000

Device Problems Computer Software Problem (1112); Application Program Problem: Dose Calculation Error (1189)

Patient Problem No Patient Involvement (2645)

Event Date 02/19/2019

Event Type  malfunction  

Event Description

A user of viewray's mridian system s/n (b)(4) reported a defect where the dose calculation result shows a difference when compared to the result calculated in the planning step with forward calculation.The anomaly reported from these two sites impacts the treatment planning and delivery system (tpds) software and identified a scenario where a discrepancy between optimization and planning forward dose calculation between adaptive optimizations and aqa dose calculations can occur.No injury has occurred.Investigation determined that in some cases the tpds sequencer may produce a beam segment with a negative beam weight.Beam weights with negative values are intended to be discarded by the sequencer.If the software does not identify the negative segments and discard them, they are given to the dose engine (referred to as kmc in what follows) for segment dose calculation.In kmc, the linac source finds the negative beam weight and returns an error from the set segments call.However, when this issue occurs the error message is ignored by the dose calculator and it proceeds with segment dose calculation.The linac source will not set the segment shapes for the segments that follow the negative beam weight segment; it simply returns the error at the negative beam-on-time segment without finishing the loop over segments, resulting in the use of incorrect segment shapes and hence in a wrong dose calculation.As a result, when this issue occurs there is a large discrepancy between the optimized dose and the calculated dose.

Manufacturer Narrative

Added missing information operator of device.This was a foreign event report; the initial mdr did not have the "foreign" or "health professional" checked.The recall number was inadvertently not entered in the initial report.

• Brand Name: MRIDIAN LINAC
• Type of Device: RADIATION THERAPY
• Manufacturer (Section D): VIEWRAY, INC.; 815 e. middlefield rd.; mountain view CA 94043
• MDR Report Key: 8430226
• MDR Text Key: 139185718
• Report Number: 3011233554-2019-00002
• Device Sequence Number: 1
• Product Code: IYE
• Combination Product (y/n): N
• PMA/PMN Number: K170751
• Number of Events Reported: 1
• Summary Report (Y/N): N
• Report Source: Manufacturer
• Source Type: foreign,health professional
• Remedial Action: Recall
• Type of Report: Initial,Followup
• Report Date: 05/20/2019

1 Device was Involved in the Event

1 Patient was Involved in the Event

• Is this an Adverse Event Report?: No
• Is this a Product Problem Report?: Yes
• Device Operator: Health Professional
• Device Model Number: 20000
• Device Catalogue Number: 20000
• Was Device Available for Evaluation?: Yes
• Initial Date Manufacturer Received: Not provided
• Initial Date FDA Received: 03/18/2019
• Supplement Dates Manufacturer Received: 03/18/2019
• Supplement Dates FDA Received: 05/20/2019
• Is This a Reprocessed and Reused Single-Use Device?: No
• Removal/Correction Number: 3011233554-03-18-2019-2C
• Patient Sequence Number: 1