Event Notification Report for April 02, 2021

AGREEMENT STATE REPORT - FAILURE TO REPORT UNDERDOSE TO PATIENT

The following was received from the state of Ohio via email:

"During a routine inspection an unreported medical event [that occurred in 2019] involving Yttrium-90 'SirSpheres' was discovered. During patient treatment the licensee encountered increasing resistance to the delivery of the microspheres, leading the licensee to believe the patient had reached stasis. After further investigation the licensee determined the cause of the resistance was clogging of the microcatheter. The dose delivered to the patient was 79.2 percent of the prescribed dose. A subsequent treatment was given to the patient to make up for the underdose. At the time the licensee's procedures did not consider this as a reportable event. The reportable event procedures have been updated."

Ohio Item Number: OH210001

A Medical Event may indicate potential problems in a medical facility's use of radioactive materials. It does not necessarily result in harm to the patient.

PART 21 REPORT - FAILURE OF AMETEK 300V, 250A CLAMP DIODES

The following is a synopsis of a Part 21 interim report received by email:

"COMPONENT DESCRIPTION - 300V, 250 A clamp diodes with Vishay/International Rectifier part numbers IN3737 and IN3737R and Ametek part numbers 07-600250-00 and 07-600251-00, respectively.
Diode failures occurred in 20kVA Inverters, Ametek part number 85-VC0200-41 with serial numbers C84733-0211 and C84733-0511. Two failed diodes returned for evaluation were manufactured in India in 2004.

"PROBLEM EXPERIENCED - TVA has experienced 5 diode failures since November of 2017. The diode failures experienced at TVA resulted in alarms for abnormal conditions and equipment alarms for fan failure, inverter fuse blown, and inverter failure. The equipment will transfer to bypass when a diode fails.

"POTENTIAL CAUSE - Diodes installed in the TVA equipment were shorted in most cases and degraded in one instance. Only two of the shorted diodes were sent to AMETEK SCI for evaluation.

"While the precise cause of this failure is unknown, diode failures are generally attributed to transient voltage spikes and overheating. TVA did indicate there have not been any transient events on the DC bus that could have caused this failure.

"The inverters at TVA are loaded below 50%. This could contribute to increased heat and stress on the diodes due to increased current draw. However, test data from the original testing of the equipment at no load did not show elevated temperatures on the diodes.

"EFFECT ON SYSTEM PERFORMANCE - Failures described above could result in loss of output voltage and transfer of the static switch to the bypass source which could result in potential loss of load.

"EVALUATION OF THE POTENTIAL DEFECT - AMETEK is sending the parts to the original manufacturer for further evaluation with the intent to obtain more insight on the interior condition of the diodes. The targeted completion date for this evaluation of the two diodes returned is June 1, 2021."