AAPM TG-100 : A new paradigm for quality management in radiation therapy

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1 AAPM TG-100 : A new paradigm for quality management in radiation therapy M. Saiful Huq, PhD, FAAPM, FInstP Professor and Director of Medical Physics University of Pittsburgh Cancer Institute and UPMC CancerCenter Pittsburgh, Pennsylvania, USA 1

2 Disclosures I have nothing to disclose 2

3 Acknowledgement Special thanks to Frank Rath from the University of Wisconsin because I have taken many slides shown in this presentation from his summer school presentations. 3

4 Authors of TG100 M. Saiful Huq Benedick Fraass (Chair) Peter Dunscombe John Gibbons Geoffrey Ibbott Sasa Mutic Ellen Yorke (Vice Chair) Arno Mundt Jatinder Palta Frank Rath Bruce Thomadsen Jeffrey Williamson 4

TG100 analysis of causes of failure for IMRT

35% Inadequate communication 10% 5 Inadequate

5 TG100 analysis of causes of failure for IMRT Lack of resources 6% Hardware/Software failure 9% Design failure 5% Inadequate commissioning 3% Defective materials/tools 2% Human failure 35% Inadequate communication 10% 5 Inadequate training 15% Lack of standardized procedures 15%

6 Recent reports 2000 As technology and processes change Retrospective approaches to QM are not sufficient All-inclusive QC checks may not be feasible Develop proactive approaches to failure modes Evaluate risks from each failure mode Develop risk based approaches to QM

7 Safety approach in industry Hazard identification and control approach is the basis for safety planning procedures for manufacturing The design phase of the ISO safety strategy includes identifications of hazards assessment of the associated risk removal of the hazards as much as practicable

8 Quality management in industry Systematic application of specific tools that improve process controls producing more consistent and closer to optimal outcomes and reduce the risk of mistakes, errors or hazardous outcomes

9 Process controls Process controls for grilling a steak Experience/training how much charcoal to pile in the middle of the grill, etc. Measurement tools watch (steak goes on the grill 20 minutes after igniting the coals) Because there are some variables that are difficult to control meat thermometer (135 deg. F) 9

10 Healthcare environment Can the concept of risk identification and process control be applied to healthcare to improve the quality of care for patients? Yes, of course. Healthcare situations readily lend themselves to a similar risk identification and control approach

11 What is risk? Risk: frequently defined as the answers to three questions What can go wrong? How likely is it to go wrong? What are the consequences if it goes wrong?

12 Risk assessment Risk assessment is the process of analyzing the hazards involved in a process Many risk assessment and analysis tools/techniques exist in industry These tools can be easily adapted to RT to enhance safety and quality of treatment process TG100 used some of these tools to develop new guidelines for RT QM

13 Risk assessment tools Process tree (mapping) Failure mode and effects analysis (FMEA) Fault tree analysis (FTA) Establishment of a risk based QM program Used IMRT as a case study

14 What is a process tree? Visual representation of the various steps in a process Demonstrates the flow of steps from process start to end Delineate and then understand the steps in the process

15 Simple example of a process map patient enters linac vault setup patient to CT marks shift treat TP shift instruction Courtesy: Darek Brown 15

16 Complicated example: TG100 IMRT process tree Subsequent tx (Day N) Immobilization and positioning Other pretreatment imaging Initial treatment planning directive Treatment planning Start of tx Plan preparation End of tx Patient database information entered Transfer images and other DICOM data Plan approval CT simulation RTP anatomy contouring Initial tx (Day 1)

17 TG100 IMRT process tree Imaging and diagnosis 2 Immobilization and positioning Review of patient medical history 1 Patient database information entered Data into electronic Database 22 Data into written chart 22 Immobilization equipment fabricated Immobilization equipment documented, labeled, and stored Information on Previous or concomitant treatment 22 3 CT simulation 4 Other imaging Imaging Studies Immobilization equipment documented, labeled, and stored Immobilization for Imaging study Immobilization equipment fabricated Patient prepped (contrast, tattoos, BBs etc.) Set up data documented Patient Identified Patient informed Of imaging requirements Position patient Make images Images Interpreted 1 Patient Position Recorded in database 6 Initial treatment planning directive 5 Transfer images Specify images for target/structure delineation 11 Specify protocol for delineating target and structures 17 Specify registration goals 23, 38 Indicate motion/uncertainty Management 13, 14 Suggest initial guidelines for treatment parameters Special Instructions (pacemakers, allergies, preps, etc.) 9 Specify dose limits and goals 26 Account for previous treatments or chemotherapy 4 Transfer Other datasets Transfer CT Dataset 41 7 RTP anatomy contouring 8 Treatment planning Save patient 4D representation Delineate ROIs and planning structures Edit density map for artifacts MD: delineate GTV/CTV 2,5 PTV construction Protocol for delineation of targets 17 Import and fuse images 16 Enter prescription And planning constraints 18, 21, 45 Setup fields Setup dose calc parameters Optimization/ Dose calculation 12, 31 Evaluate plan 10, 28 Protocol for PTV Margin 6 Specify PTV Margin Boolean operations 29, 46 Select Images 25 4D imaging correct 13 Create case Specify ROI for optimization 19 Calculate dose to optimization points and dose distribution 12, 31 Heterogeneity correction 30 Optimization settings 45 Optimization ROI 33, 44 Run leaf sequencer Evaluate leaf sequencer Evaluate delivery system limitations 10 Plan preparation 9 Plan approval Approve plan 7, 20 Enter demographics Specify treatment course Delivery protocols Prepare DRR and other images Define localization imaging Annotate localization anatomy Order fields Prepare paper chart Prepare electronic chart 15 Complete formal prescription 36 Check version of plan and patient ID Automatic data entry and plan modification Transfer patient data to treatment delivery 15 Manual data entry and plan modification 39 Scheduling Documentation Monitor Pt/Tx 37, 43 Treatment 3 Tx Unit operation and calibration 3 Motion management 8 Treatment accessories 24 Treatment settings Positioning Time out 12 Subsequent treatments Imaging (port films, CBCT, etc) 27 Patient information 35 Patient ID Treatment Site Scheduling Patient information Pt prep 35 Imaging Positioning Pt changes noted 42 Treatment accessories 24 Motion Management 8 Treatment 3 Changes noted 32, 34 Changes correct 40, 42 Tx Unit operation and calibration 3 Monitor Pt/Tx 37, 43 Documentation Chart filing Successful treatment Initial treatment Treatment settings

18 FMEA A risk assessment tool used to identify weaknesses or deficiencies (inadequate controls) in processes that could lead to mistakes, errors, and potential hazardous outcomes

19 Strategy for improving patient safety: FMEA & FTA Begins with a complete and thorough understanding of the process flow charts, process maps Perform a Process FMEA (P-FMEA) to identify weaknesses or inadequate controls in the process Develop process controls that either reduce the risk or improve the process Use FTA to identify root causes of potential process failures and develop recommendations to improve quality control of the process

20 Completing an process FMEA Create a team Ideally cross functional representing every function involved in the process Oncologists, medical physicists, dosimetrists, therapists, IT personnel, administrators Effort should be led by a facilitator trained in or familiar with the tools used in the analysis Consider providing training

21 Completing an process FMEA Select a process key step Scale is important Opportunity Quality issues, past problems, not happy with the level of success, Realistic opportunity to make improvements Complexity or size

22 Process FMEA for each step in a process Detect FM: Inability of a process step to produce the desired optimal outcome Failure Modes Effects Cause

23 Completing an FMEA For a given process: Step Potential failure modes Potential causes of failure Potential effects of failure O S D RPN Comment RPN = O x S x D [ 1 RPN 1000 ] 23

24 Completing an FMEA 1. For each process step identify all potential failure modes always best to define failure modes as not meeting process requirements 2. For each potential failure mode identify all of the causes that could produce that failure a. Focus on process related causes of failure modes

25 Completing an FMEA 3. For each potential failure mode identify the effects of that failure mode

26 Completing an FMEA 4. Current controls judge the current capabilities of the process controls to: a. Prevent the cause of a failure from occurring b. Detect a failure when it occurs c. Moderate the severity of a failure when it occurs

27 Completing an FMEA Most effective and lowest cost controls are those that prevent causes of failure modes

28 FMEA ranking scales for Occurrence, Detection, Severity* Occurrence of the cause of failure mode : O Detection of failure mode: D Severity of the effect when failure mode occurs: S *Not used by TG100

29 Completing an FMEA Risk Priority Number (RPN) Occurrence ranking X Severity ranking X Detection ranking Range of RPNs (1-1000) RPN of 125 or higher is problematic either in terms of safety or process capability Typical scenario RPNs over 400! Highest RPNs must be addressed first Then work down to lower risk process steps 29

30 Completing an FMEA Risk Priority Number (RPN) Beware of patterns potentially hidden by low overall RPNs Occurrence = 10, Severity =10, Detection=1 - RPN of 100 but Occurrence=1, Severity=10, Detection=10 RPN of 100 but. Severity of 10 even if Occurrence and Detection are both a 1 can you or do you want to risk it? 30

31 Top/Down FMEA approach Start with the major branches of the selected process Perform a PFMEA to identify which branches are the weakest (most likely to produce sub-optimal results or errors/mistakes Drill down deeper into those branches more detailed process map and PFMEA

32 Fault Tree Evaluates propagation of failures Visual representation of propagation of failures Begins on the left with a failure mode Works backwards in time (to the right to identify causes of failure) 32

33 Fault Tree Evaluates propagation of failures Visual representation of propagation of failures Error in data Begins on the left with a failure mode Error in Works calculated backwards value in time for patient OR (to the right to identify causes of failure) Error in data input Error in calculation algorithm Error in prescription 33

34 Fault Tree Error in data Error in QC Error in data input Error in Calculated value for patient Error in calculation Error in QA Error in QC Error in Calculation algorithm Error in QC Error in prescription Error in QC 34

35 TG100

36 Summary Current QA guidance documents are based on prescriptive approaches evaluating technical performances of radiotherapy equipment There has been a growing recognition that quality and safety impairment arises from weakness in radiotherapy processes Hence the change in approach in QM in TG100 36

37 Thank you It is useful to report all accidents before consequences appear It is impossible to make anything foolproof because fools are so ingenious. Arthur Bloch, Murphy s law Our job is not to prevent errors, but to keep the errors from injuring the patients. Lucian Leape

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