radiation accident

Radiological accidents:

CT Brain Perfusion ScansOverdose.

Moayyad AlssabbaghMGQ120003

Master of Medical Physics 2012/2013University of Malaya

Radiological accidents: CT Brain Perfusion Scans Overdose

In this Presentation:

• What is CT perfusion scan

• Accident description

• Accident causes

• The consequences, impact and implications

• Lessons learned and recommendations


• What is CT Perfusion scan:

It’s a kind of diagnostic x-ray scans produce cross-sectional images or 'slices' of specific areas of the head.


• Why:

For stroke test which is the evaluation of blood flow in the brain.

• Causes:

It happens when blood flow to a part of the brain stops, which lead to brain cells die or causing permanent damage due to lack of blood and oxygen.

• A stroke is called also a "brain attack.“


Accident description

• In Oct. 2009, the first notification was reported (FDA)

• Patients undergoing computed tomography (CT) brain perfusion scans were accidently exposed to excess radiation doses.


Accident disc. - Cont.

• Some patients reported obvious signs of excessive radiation exposure following their scans, such as hair loss or skin redness, which called attention to the problem.


Problem Description – cont.

• Over 385 patients from six hospitals all in California alone, were exposed to excess radiation during CT brain perfusion scans

• Other cases appeared:

– More than 200 patients in a hospital in Los Angeles

– And dozens more at a hospital in Huntsville, Alabama, were being overdoses too.


How much radiation dose they received?

• Instead of receiving the expected dose of 0.5 Gy to the head (depend on patient size, age, condition and scanner design, etc.), these patients received 3-4 Gy (approximately eight times) which is in some cases resulted in hair loss and erythema.


• How did this happen? (Accident causes)

• An investigation by the Food and Drug Administration (FDA) was set

• Technicians intentionally used high levels of radiation to get clearer images. (Recommendation by the companies that supplied the scanners)

• No manufacturer-defined protocol provided to get reasonable and appropriate image quality and dose.

• Hospitals modified their own scanning protocols .


The consequences, impact and implications• In Addition to hair loss and skin redness, patients experienced

headaches, memory loss and confusion.

• Over time, excessive radiation exposure can place patients at increased risk for long-term radiation effects, such as risk of brain damage and cancer.


• It also has social effects, which may be reflected on the psychological state of the patient, which can also lead to work loss.

Mr. Alain Reyes’s co-workers at a shipping company avoided him, and his boss sent him home, fearing he had a contagious disease.


Lessons learned and recommendations• The problem may not be detected because the dose is not high

enough to cause radiation injury.

• Regulatory agencies was unaware of those doses but started to investigate after a news paper brought them to the public attention.

• Providing particular information, protocols and training on brain-perfusion to all facilities that receiving CT equipments.

A medically-needed CT scan that does not expose the patient to unnecessary radiation has benefits that far outweigh the radiation

risks


Thank you for

listening

• References

• U.S. Food and Drug Administration

http://www.fda.gov/MedicalDevices/Safety/AlertsandNotices/ucm193293.htm

http://www.fda.gov/MedicalDevices/Safety/AlertsandNotices/ucm185898.htm

• The New York Times news paper. The New York Times Company (NYSE: NYT)


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