Dose Course 2018_Flipping book

Errors in radiation oncology: A study in pathways and dosimetric impact Eric Klein, Robert E. Drzymala, James A. Purdy and Jeff Michalski Journal of applied Med. Phys. 2005

Error type:

Typical # of fraction in which it was detected

Method of detection

# of events

#of record and verify

Incorrect treatment coordinate(s) Wrong gantry angle Wrong or omitted cerrobend block Wrong field size Incorrect collimator angle Missing compensation filter Incorrect calculation

first

Port film

19

7

first first

Port film Port film

15 15

8

Errors over a 30 months on 7 linacs equiped with R&V system . No complete electronic transfer of treatment set-up data.

N/A

2 to 5 fractions

In vivo dosimetry; physicist chart review

11

N/A

first first

Port film. Port film

9 8

8 3

2 to 5 fractions

In vivo dosimetry; physicist chart review

6

N/A

Incorrect MU Wrong photon energy

2 to 5 fractions 2 to 5 fractions

In vivo dosimetry In vivo dosimetry

5 3

4 3

Missing or incorrect MLC shape

first

Port film

3

Detected errors 49/3900

Incorrect wedge direction

1,5,16 fractions

Later diode check; physics check Physicist review

3

Incorrect number of fractions for given set of fields Incorrect or rotated compensating filter Patient treated head to gantry but scanned foot to gantry

1 to 3 fractions

3

2

With entrance in vivo dose measurements 30/3900

2 or 11 fractions

Therapist discovery; in vivo dosimetry

2

N/A

First fraction

Port film

1

N/A