Background
Methods
SBRT with Cyberknife®
Failure Modes and Effects Analysis (FMEA)
Results
Sub-process | N | Potential failure mode | Potential causes of failure | Potential effects of failure | S | O | D | RPN |
---|---|---|---|---|---|---|---|---|
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 |
Sub-process | N | Potential failure mode | Potential causes of failure | Potential effects of failure | S | O | D | RPN |
---|---|---|---|---|---|---|---|---|
IX. Patient’s instruction on how to request the intervention of the technician in case of need (voice call via intercom and/or lifting a hand) | 1 | Absent or insufficient patient’s information on the request for help in case of need | Negligence, difficult communication with the patient, inattention, haste (intensive scheduling)
| Lack of assistance in case of need, discomfort to the patient | 10 | 1 | 3 | 30 |
XVI. Verifying the right vision of the patient from the control room with swiveling cameras | 2 | Failure to verify the vision of the patient from the cameras, suboptimal patient’s vision | Negligence, inattention, haste (intensive scheduling), superficiality, cameras not working, presence of objects in the treatment room that limit the vision of the patient | Lack of monitoring (i) possible collisions between the treatment manipulator and the patient; (ii) the patient’s welfare; (iii) possible collisions between the treatment manipulator and any object present in the treatment room. Lack of action in anomalous situations; treatment not in accordance with the planned one; postponement of the treatment session | 10 | 1 | 3 | 30 |
XVIII. Checking the correctness of patient and treatment plan data, check that the Synchrony field displays “Yes” | 3 | Failure to verify the patient and treatment data correctness, failure to verify that the Synchrony field is active | Negligence, inattention, haste (intensive scheduling), interruption of the activity, patient clinical record not present at the time of treatment | Wrong dose delivery (in case of wrong prescription of dose or number of fractions in the planning stage), elongation of the work time, unnecessary live X-ray images acquisition, postponement of the treatment session | 10 | 2 | 8 | 160 |
XXX. Selection of the appropriate size of the safety zone (small/medium/large), based on the patient’s size | 4 | Not appropriate selection of the size of the safety zone | Negligence, superficiality, inattention, haste (intensive scheduling), wrong estimate of the actual size of the patient | Risk of collision between the treatment manipulator and the patient (if PDP alerts are ignored), elongation of the treatment time (for PDP alerts) | 10 | 2 | 2 | 40 |
XXXVIII. At the end of each session, compilation of the specific section in the worklist by the technician who delivered the treatment | 5 | Missed/wrong/partial/not clear compilation of the worklist at the end of each session | Negligence, inexperience, inattention, haste (intensive scheduling), interruption of the activity, patient clinical records not present at the end of the treatment, shift of technicians during the treatment (high workload) | Incorrect delivery of treatment plans (wrong plan, wrong day,…) if multiple lesions (plans) are present, incomplete patient clinical records, slowdown of the workflow. | 8 | 2 | 5 | 80 |
Sub-process | N | Potential failure mode | Potential causes of failure | Potential effects of failure | S | O | D | RPN |
---|---|---|---|---|---|---|---|---|
I. Call of the patient in the waiting room | 1 | The patient is called but a different one answers/ The patient is not called | Identification does not include patient’s name, surname, date of birth, photo-Patient was not informed of modifications regarding the time of the appointment, patient is late | Delivery of the treatment to the wrong patient -the radiotherapy treatment is not delivered or is administered late | 10 | 1 | 2 | 20 |
II. Verification of the patient’s identity at the treatment’s room entry by asking personal data confirmation | 2 | Patient’s identity verification by checking all the personal data not performed | Only patient’s surname check | Possibility of mistaking patients and therefore treatments | 10 | 2 | 3 | 60 |
X. Check of the correct view of the patient from the treatment workspace using adjustable video cameras | 3 | Patient is not monitored during treatment | Video cameras are not correctly oriented or functioning | Cyberknife may hit the patient without the operator noticing it. Patient may be in need and not been seen | 9 | 2 | 2 | 36 |
XII. Patient selection using personal data (Name and surname) | 4 | Wrong patient’s name-Personal data check is not performed | Patient is called without checking patients’ list-Lapse of memory | Delivery of the treatment to the wrong patient-possibility of mistaking patients and therefore treatments | 10 | 2 | 5 | 100 |
XIII. Check of the correct treatment plan and of the number of fractions as described on the report print | 5 | Delivery to the patient of a wrong plan-plan check not performed | Personal data and patient ID on the printed plan not checked-lapse of memory | Patient receives wrong irradiation-possibility of mistaking patients and therefore treatments | 10 | 2 | 3 | 60 |
XV. Check of patient’s name, surname and medical ID by flagging the appropriate box for acceptance | 6 | Patient’s personal data not checked | Automatic action- Lapse of memory | Wrong patient or treatment-possibility of mistaking patients and therefore treatments | 10 | 2 | 7 | 140 |
XVI. Check of: plan name, tracking method (XSight spine), path, number of fraction, collimator type and aperture-flag of the appropriate box for acceptance | 7 | Data check is wrong or not performed | High workload-lapse of memory | Wrong patient or treatment-possibility of mistaking patients and therefore treatments | 10 | 2 | 7 | 140 |
XVII. Accurate alignment of the patient by comparing DRR and live images: adjustment of the values and tolerance levels defined in the image parameters window-adjustment of the X Sight Spine ROI dimensions | 8 | Wrong alignment-Threshold levels of the different parameters not modified when necessary | Difficulty to visually identify spine tract in the live images-Lapse of memory, insufficient experience of the operator with the treatment system | Treatment not properly delivered-longer time to start treatment | 10 | 1 | 4 | 40 |
XIX. Setting of the most appropriate patient size | 9 | Appropriate patient size not set | Lapse of memory, insufficient experience of the operator with the delivery system | Possible collisions or errors of the PDP system slowing down treatment | 9 | 2 | 5 | 90 |