MAUDE Adverse Event Report: ACCURAY INCORPORATED CYBERKNIFE TREATMENT DELIVERY SYSTEM; MEDICAL LINEAR ACCELERATOR

Model Number G4

Device Problems Use of Incorrect Control/Treatment Settings (1126); Adverse Event Without Identified Device or Use Problem (2993)

Patient Problem Unintended Radiation Exposure (4565)

Event Date 06/06/2022

Event Type  Injury  

Manufacturer Narrative

A customer contacted accuray indicating there was a potential mistreatment that occurred at their site.The customer needed assistance reviewing the patient treatment.The patient treatment was for a synchrony spine tracking plan to be delivered in two fractions for a total of 5233.68 cgy.On the first day of treatment, 40% false nodes were observed, but treatment proceeded.On the second day of treatment, the physicist reviewed the alignment and discovered that the patient was mis-aligned by one vertebral segment on the first day.Once the alignment was corrected on the second day, the false nodes dropped to 7%.The patient has been fully treated in the correct location, indicating that 2616.84 cgy was delivered to an incorrect location of the spine.This event is currently under investigation.

Event Description

A customer contacted accuray indicating there was a potential mistreatment that occurred at their site.

Manufacturer Narrative

A customer contacted accuracy indicating there was a potential mistreatment that occurred at their site.When accuracy reviewed the patient treatment data, it was confirmed that a mistreatment occurred due to a use error.Actual parameters of spine tracking mesh were set at default parameters which means that the planner did not reset or expand mesh to the proper size.Tracking range being used was 10mm (default is 20mm); tracking mesh (roi width) values not set appropriately during planning.Spine tracking mesh (roi width) was left at default based on treatment plan.The spine tracking mesh from this case was too small and did not cover all bony anatomy.Because of small tracking mesh (roi width) and decreased tracking range, the live image was not locked on to planning image, customer will see high number of false nodes (fn), in this case 40%.This is technically in range as fn range goes up to 50%.Recommendations for fn for a "normal" spine is <20%.The fn are displayed as orange lines within the tracking mesh (roi width) and should only be located on the outside edges of the mesh or in soft tissue.In this case, the mesh had several fn (orange lines) within the middle of the mesh, which is an indicator of poor alignment.When higher fn values are present, the therapist are trained to analyze them to ensure the fn numbers are correct, and the anatomy matches the drrs'.Despite 40% being a clinically acceptable number of fn to proceed to treatment, in this case the value was too high and should have been closely evaluated.Visually, the therapist should have seen that the live vertebral body image was not locking onto the drr / planning image.Patient received a single fraction of 2.6 gy to an incorrect vertebra.This does not approach the dose volume histogram limit of <14gy in a single fraction to spinal cord according to mobius3d dose volume histogram; therefore, this event is not likely to lead to a serious injury.This event has also been determined to no longer meet the definition of a serious injury based on this assessment.

• Brand Name: CYBERKNIFE TREATMENT DELIVERY SYSTEM
• Type of Device: MEDICAL LINEAR ACCELERATOR
• Manufacturer (Section D): ACCURAY INCORPORATED; 1209 deming way; madison WI 53717
• Manufacturer (Section G): ACCURAY INCORPORATED; 1209 deming way; madison WI 53717
• Manufacturer Contact: daniel biank ; 1209 deming way; madison, WI 53717 ; 6088242971
• MDR Report Key: 14843415
• MDR Text Key: 295118030
• Report Number: 3003873069-2022-00010
• Device Sequence Number: 1
• Product Code: IYE
• Combination Product (y/n): N
• Reporter Country Code: US
• PMA/PMN Number: K170788
• Number of Events Reported: 1
• Summary Report (Y/N): N
• Report Source: Manufacturer
• Source Type: Health Professional
• Reporter Occupation: Other Health Care Professional
• Type of Report: Initial,Followup
• Report Date: 10/17/2022

1 Device was Involved in the Event

1 Patient was Involved in the Event

• Date FDA Received: 06/28/2022
• Is this an Adverse Event Report?: Yes
• Is this a Product Problem Report?: No
• Device Operator: Health Professional
• Device Model Number: G4
• Was Device Available for Evaluation?: Yes
• Is the Reporter a Health Professional?: Yes
• Date Manufacturer Received: 06/07/2022
• Was Device Evaluated by Manufacturer?: Yes
• Date Device Manufactured: 07/01/2010
• Is the Device Single Use?: No
• Is This a Reprocessed and Reused Single-Use Device?: No
• Type of Device Usage: Reuse
• Patient Sequence Number: 1
• Patient Outcome(s): Other