MAUDE Adverse Event Report: ELEKTA LTD XVI; ACCELERATOR, LINEAR, MEDICAL

Catalog Number 10690

Device Problems Fail-Safe Design Failure (1222); Fail-Safe Problem (2936); Device Handling Problem (3265)

Patient Problem Not Applicable (3189)

Event Type  malfunction  

Manufacturer Narrative

A shift of kv source of 8mm would result in an image (and therefore patient shift) of 4.3mm.However, the risk assessment will consider that the kv source arm could stop at any position either greater or less than this amount under the fault condition.Detection of a small shift would be difficult compared to a large shift, though a small shift has a low severity.To consider worst case scenario, a shift of kv iso centre of 10mm has been applied (high severity but low detectability), kv source shift of 18.7mm.Severity: normal treatment: a 6mm error would represent a major mistreatment.Normal treatments are unlikely to be non coplanar.Stereotactic treatment: a 3mm error would represent a major mistreatment.Likelihood: occasional - this an uncommon use error (heavy handed use).This fault has not been reported before.Reduced to remote- ifu section 3.1.2.1 use the user handle and check source arm is now locked in extended position, with no movement possible.(if the kv source arm is not fully extended and locked in position, then an inhibit condition is raised in xvi software).A fault in the logic on the atp pcb creates a race condition triggered by rapid activation/deactivation of the arm position switch.Toggling the hardware switch or resetting the generator or linac would have also cleared this fault.As machines are normally restarted daily, if the fault had not been detected by some other means, it would not exist more than day.Ifu section 19.3.2 weekly qa checks - kv source arm interlock.Users may be able to detect the hazardous situation and intervene before harm occurs following procedural activities or passive information displays.The user can align the patient using room lasers and mv imaging techniques leading to large shifts being detected.Shifts >25mm (or less) would normally be investigated prior to treatment as you can't asu.Alternatively, this could be detected pre or post treatment as a random or unusual shift on review of a patient would be investigated.This reduces the likelihood of leading to harm to improbable.The risk of mistreatment has been assessed major and rv4.The fault has not been reported before.This event occurred with trainee personnel.Evaluation of design and conditions.

Event Description

The kv source arm was not in the extended (imaging) position; however, the kv beam was not inhibited.This means that kv images used for patient positioning could be taken with the kv source at an incorrect position.With the kv source shifting in the g direction the kv iso-centre will shift also in the g direction by an amount proportional to the ratio between the kv source/iso centre and the panel/iso centre.Trainee personnel were present at the hospital and it was reported that the users were heavy handed with the kv source during arm extension.The dampener on the kv source arm assembly was checked and appeared to function correctly.The shift of the kv source position was estimated to be approximately 8mm out of position in the g direction, this was the closest the arm could be without dropping into the locked position.The issue was fixed on site by turning the switch on the atp pcb in the kv generator off and then on again.Xvi 4.2.1 should have the switch in the off position.The inhibit then worked as intended.The hospital added a visual marker on the kv source (room lasers) and added kv source position to daily qa check.Customer is reviewing cases that had a shift larger than 8mm.

• Brand Name: XVI
• Type of Device: ACCELERATOR, LINEAR, MEDICAL
• Manufacturer (Section D): ELEKTA LTD; linac house; fleming way; crawley, west sussex RH10 9RR; UK RH10 9RR
• Manufacturer (Section G): ELEKTA LTD; linac house; fleming way; crawley, west sussex RH10 9RR; UK RH10 9RR
• Manufacturer Contact: gpms ; linac house; fleming way; crawley, west sussex RH10 -9RR ; UK RH10 9RR
• MDR Report Key: 5702676
• MDR Text Key: 46663794
• Report Number: 9617016-2016-00005
• Device Sequence Number: 1
• Product Code: IYE
• Combination Product (y/n): N
• Reporter Country Code: US
• PMA/PMN Number: 051932
• Number of Events Reported: 1
• Summary Report (Y/N): N
• Report Source: Manufacturer
• Source Type: other
• Reporter Occupation: Health Professional
• Type of Report: Initial
• Report Date: 06/07/2016

1 Device was Involved in the Event

1 Patient was Involved in the Event

• Date FDA Received: 06/07/2016
• Is this an Adverse Event Report?: No
• Is this a Product Problem Report?: Yes
• Device Operator: Health Professional
• Device Catalogue Number: 10690
• Was Device Available for Evaluation?: No
• Is the Reporter a Health Professional?: Yes
• Date Manufacturer Received: 05/11/2016
• Was Device Evaluated by Manufacturer?: No
• 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