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LARA - MI Department of Licensing and Regulatory Affairs | LARA MI Department of Licensing and Regulatory Affairs | LARA
MI Department of Licensing and Regulatory Affairs | LARA
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Therapy Accelerator Misadministrations in 2011

Event
Summary A patient was to receive an emergency treatment over a weekend. The prescribed dose was 3 fractions of 400 cGy with more treatment to follow after the weekend. Due to an error in the calculation by the radiation therapist, the patient received only 212 cGy per fraction. Two fractions were delivered and the error was discovered before the third fraction was delivered.
Root Cause Human error in the dose calculation.
Corrective Action The prescription for the remainder of the regular non emergent radiation treatments accommodated the under-dose from the first 2 fractions.
Effect on Patient No adverse effects in the short or long term related to the 2 under-dose treatments delivered.
Event
Summary A patient had a gross tumor volume surrounded by a clinical target volume (CTV). However, only 76% of the volume of the CTV received the prescribed dose of 45 Gy while the remaining 24% of the volume received 34.2 Gy. Hence, part of the CTV was under-dosed by 24% (10.8 Gy/45 Gy).
Root Cause Human error in the dose calculation due to mis-interpretation of the prescription by the dosimetrist. A treatment planning guide sheet filled by the physician was also confusing for the dosimetrist.
Corrective Action The treatment planning guide sheet will be revised to be less confusing, the dosimetrists are to label the structures with their associated doses, physics review needs to scrutinize the plans from all dosimetrists and the dosimetrist has been given an extended probation period.
Effect on Patient No adverse effects in the short or long term because of this underdosage to the CTV.

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