1. IAEA E-learning Program
Safety and Quality in Radiotherapy

2. Safety and Quality in Radiotherapy
MODULE 6: root cause analysis 1: human factors & basic causes
Sections:
6.1 Principles of Root Cause Analysis
6.2 Rasmussen’s human factors model
6.3 The New York State Incident
6.4 The Epinal Incident
6.5 The Toulouse Incident
In this module, we will be discussing the principles of root cause analysis, Rasmussen’s human factors model, the New York incident, the Epinal incident and the Toulouse incident.

3. Safety and Quality in Radiotherapy
MODULE 6: root cause analysis 1: human factors & basic causes
Sections:
6.1 Principles of Root Cause Analysis
6.2 Rasmussen’s human factors model
6.3 The New York State Incident
6.4 The Epinal Incident
6.5 The Toulouse Incident
Having learned the basics of Root Cause Analysis and reviewed a model for human performance we’ll now apply this knowledge to the New York incident. In this section we’ll go through the first three steps of a Root Cause Analysis which we discussed in Section 1 of this Module.

4. Safety and Quality in Radiotherapy
MODULE 6: root cause analysis 1: human factors & basic causes
Section 3: The new york Incident
Two cautions:
We will reconstruct these example incidents from what we know. However, we don’t have perfect knowledge of any of these incidents. For this reason, our assessment may differ from any formal analyses undertaken by regulatory or professional organizations.
Even with comprehensive, detailed descriptions of incidents, interpretation may depend on the the person(s) reporting and, particularly, investigating the event.
We have to have this caution again as we don’t know everything that happened so our conclusions can’t be too firm.
Both of these factors can play a role in the analysis of incidents in real life where our knowledge of events is never complete and personal judgment is generally required.

5. Safety and Quality in Radiotherapy
MODULE 6: root cause analysis 1: human factors & basic causes
Section 3: The new york Incident
OBJECTIVES
To develop a graphical description of the events contributing to the incident.
To explore possible basic causes of the incident.
To select appropriate basic causes from the SAFRON taxonomy.
The section objectives are: to develop a graphical description of the events contributing to the incident, to explore possible Basic Causes of the incident, and to select appropriate Basic Causes from the SAFRON taxonomy.

6. Safety and Quality in Radiotherapy
MODULE 6: root cause analysis 1: human factors & basic causes
Section 3: The new york Incident
What happened?
March 2005, somewhere in the state of New York, USA
A patient is due to be treated with IMRT for head and neck cancer (oropharynx).
March 2005, somewhere in the state of New York, USA, a patient is due to be treated with IMRT for head and neck cancer.
IAEA Prevention of accidental exposure in radiotherapy

7. Safety and Quality in Radiotherapy
MODULE 6: root cause analysis 1: human factors & basic causes
Section 3: The new york Incident
SUMMARY
Oropharynx patient was planned with IMRT.
1st four fractions were delivered correctly.
Physician changed volume to avoid teeth.
Original plan was copied and modified appropriately.
During the “Save” operation, the computer crashed.
The fluence distribution, but not the complete DRR and no MLC control points were saved.
The absence of the MLC icon and confirmation of MLC activation were not noticed at the treatment console.
QA of the modified plan was not performed until three fractions had been delivered.
This is the summary of the incident. The patient received 13 Gy per fraction for three fractions, that is 39 Gy in 3 fractions. If you remember all the details, just move on to the next slide.
The patient received 13 Gy per fraction for three fractions, i.e. 39 Gy in 3 fractions.
The patient subsequently died from his injuries.

8. Safety and Quality in Radiotherapy
MODULE 6: root cause analysis 1: human factors & basic causes
Section 3: The new york Incident
Root Cause Analysis: the key steps
To establish a group which undertakes the investigation.
Ideally an appropriate group of individuals, as discussed in Section 1 of this module, should perform the root cause analysis.
Sometimes that just isn’t possible. If you have to perform the root cause analysis on your own, go ahead.
While the investigation may be incomplete, any preventive actions you implement have the potential to benefit the clinical program.
The first key step in a root cause analysis is to establish a group which undertakes the investigation. Ideally an appropriate group of individuals, as discussed in Section 1 of this module, should perform the Root Cause Analysis. Sometimes that just isn’t possible. If you have to perform the Root Cause Analysis on your own, go ahead. While the investigation maybe incomplete, any corrective actions you implement have the potential to benefit the clinical program.

9. Safety and Quality in Radiotherapy
MODULE 6: root cause analysis 1: human factors & basic causes
Section 3: The new york Incident
Root Cause Analysis: the key steps
A detailed, preferably chronological, description of the events which preceded the incident.
Patient
overdosed
TIME
Plan sent to machine
Computer
crashes
IMRT plan
started
RO requests new plan
4 fractions
received
MLC wide
open
The second key step in a root cause analysis is a detailed, preferably chronological description of the events which preceded the incident. It’s important to note that we are not identifying causes at this stage. We need to ascertain the facts as far as we can and not speculate. If this were to be a real investigation we would talk to the people actually involved to make sure the facts, as laid out, are correct. As mentioned before, this step is very important. All those involved in the investigation need to agree that this is actually what happened.

10. Safety and Quality in Radiotherapy
MODULE 6: root cause analysis 1: human factors & basic causes
Section 3: The new york Incident
Root Cause Analysis: the key steps
An exploration of the basic or root causes of the incident, through review of relevant clinical documents and interviews with involved people.
39Gy in 3 fractions
MLC file
incorrect
MLC icon
not observed
RTs watching patient
Lack of training
Lack of risk awareness
Beam not
verified
See next
slide
TPS system
fault
The third key step in a root cause analysis is an exploration through review of relevant clinical documents and interviews with involved persons, of the basic or root Causes of the incident. Note that the lowest branch terminates quickly. It’s unlikely that we could fix a TPS system fault so we can’t go any further within our institution along this branch. The appropriate action would be to notify the manufacturer of the fault. Along the middle branch, we’ve identified, in our own words, situations that we can fix so these are valid basic causes. Had the MLC icon been observed, the therapists would probably have noticed quickly that the leaves were not moving. We’ll discuss possible corrective actions in Module 7. The top branch is continued on the next slide.

11. Safety and Quality in Radiotherapy
MODULE 6: root cause analysis 1: human factors & basic causes
Section 3: The new york Incident
Root Cause Analysis: the key steps
An exploration of the basic or root causes of the incident, through review of relevant clinical documents and interviews with involved people.
Beam not
verified
No patient specific QC
Policy not
followed
Lack of training
Lack of risk awareness
Incomplete
review
Workload
pressures
Console screen
Not verified
Risk
Awareness
Here’s the continuation of the top branch with basic causes described in our own words. It’s always important to remember that other investigators may interpret events differently and come up with a different list of basic causes. However, experience suggests there will be a high degree of overlap between the basic causes identified by different investigators looking at the same incident. For entry into SAFRON, what we have to do next is to pick from the basic causes taxonomy the basic causes which come closest to our descriptions in the right most boxes.

12. Safety and Quality in Radiotherapy
MODULE 6: root cause analysis 1: human factors & basic causes
Section 3: The new york Incident
Basic Causes
Having identified basic causes in our own words we now need to enter them into SAFRON.
Having identified basic causes in our own words, we now need to enter them into SAFRON.

13. Safety and Quality in Radiotherapy
MODULE 6: root cause analysis 1: human factors & basic causes
Section 3: The new york Incident
Basic Causes
In order to do this we have to map our “free text” basic causes onto the SAFRON taxonomy.
In order to do this we have to map our “free text” basic causes onto the SAFRON taxonomy. As we discussed in Section 1 of this module it is quite likely that many of these causes are features of the entire clinical program. In other words, there could be a shortage of staff in the clinic and maybe training is not at the level it should be. So we can learn a lot about the strengths and weaknesses of a clinical program just through the analysis of one incident.
Policy not followed = 1.3 Standard/Procedure/Practice not followed.
TPS system Fault = 2.2 Defective equipment.
Risk awareness = 3.2 Inadequate design specification.
Workload pressures = 4.6 Personnel availability.
Lack of training = 6.1 Inadequate training/orientation.

14. Safety and Quality in Radiotherapy
MODULE 6: root cause analysis 1: human factors & basic causes
Section 3: The new york Incident
summary
We have:
Developed a graphical description of the events contributing to the incident.
Explored possible basic causes of the incident.
Selected appropriate basic causes from the SAFRON taxonomy.
In summary, we have developed a graphical description of the events contributing to the incident, explored possible basic causes of the incident, and selected appropriate basic causes from the SAFRON taxonomy. We will repeat these exercises for the Epinal and Toulouse incidents.