Radiation accident

Radiological accidents:

CT Brain Perfusion Scans
Overdose.

Moayyad Alssabbagh
MGQ120003

Master of Medical Physics 2012/2013
University 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


• 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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