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); Application Program Problem (2880)

Patient Problem No Patient Involvement (2645)

Event Date 04/12/2019

Event Type  malfunction  

Manufacturer Narrative

The anomaly reported from this site impacts the treatment planning and delivery system (tpds) software and identified a scenario where a discrepancy between optimization and planning forward dose calculations can occur.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 large discrepancy between the optimized dose and the calculated dose.

Event Description

A user of viewray's mridian system reported an occurrence of known defect where the dose calculation result shows a difference when compare to the result calculated in the planning step with forward calculation.No report of patient injury.

• Brand Name: MRIDIAN LINAC
• Type of Device: RADIATION THERAPY
• Manufacturer (Section D): VIEWRAY, INC.; 815 e. middlefield road; mountain view CA 94043
• Manufacturer Contact: sean delaney ; 815 e. middlefield road; mountain view, CA 94043 ; 6502520969
• MDR Report Key: 8541344
• MDR Text Key: 142818774
• Report Number: 3011233554-2019-00005
• Device Sequence Number: 1
• Product Code: IYE
• Combination Product (y/n): N
• Reporter Country Code: US
• PMA/PMN Number: K170751
• Number of Events Reported: 1
• Summary Report (Y/N): N
• Report Source: Manufacturer
• Source Type: health professional,user faci
• Reporter Occupation: Other Health Care Professional
• Remedial Action: Recall
• Type of Report: Initial
• Report Date: 04/23/2019

1 Device was Involved in the Event

1 Patient was Involved in the Event

• Date FDA Received: 04/23/2019
• 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
• Is the Reporter a Health Professional?: Yes
• Date Manufacturer Received: 04/12/2019
• Was Device Evaluated by Manufacturer?: Yes
• Date Device Manufactured: 05/14/2018
• Is the Device Single Use?: No
• Is This a Reprocessed and Reused Single-Use Device?: No
• Type of Device Usage: Reuse
• Removal/Correction Number: 3011233554-03-18-2019-2C
• Patient Sequence Number: 1