Table 1 FMEA of the treatment planning stage. Failures with RPN ≥ 80 or S ≥ 9 are listed

VI. Definition of the treatment parameters: number of fractions

1

Typing of a wrong number of fractions

Erroneous identification of the fractions number on the patient’s record, wrong patient’s record (coincidence of names), wrong typing

Wrong fraction dose administration

10

2

3

60

XII. Identification of the align centre and X sight-spine ROI height (in the case of spinal lesions)

2

Wrong positioning of the align centre and ROI height

Inexperience, presence of multiple lesions, damaged vertebrae

Tracking non-representative of the lesion’s movement (underdosage of the PTV, overdosage of the OAR)

7

2

7

98

XXXIII. Enlargement of the calculation grid to all the CT volume in the three views

3

Missed enlargement of the calculation grid to all the CT volume

Inexperience, distraction, haste, activity interruption

Missed visualization of the hot spots in areas far from target and OARs, partial evaluation of the DVH

9

2

3

54

XXXVI. Physician’s approval of the treatment plan, with eventual re-prescription of dose and number of fractions

4

Missed or wrong re-prescription of dose or number of fractions

Inexperience, distraction, haste, activity interruption, high workload, missed communication between physicist and physician

Erroneous dose delivery

10

2

4

80

XLII. Print of the report containing plan data, of the dose statistics table and of two images representative of the treatment plan (3D dose distribution, beams entry, DVH data and charts)

5

Missed or wrong printing of the plan report, of the table and images, printing of report, table and images not concerning the approved plan

Inexperience, distraction, haste, activity interruption, high workload, printing performed not contextually with the plan approval, missed communication among physicists

Missed check of the treatment plan, delivery of a sub-optimal plan or erroneous dose (in case there are other deliverable plans present)

10

1

4

40