1. A Clinical Audit in Stereotactic Radiotherapy Lucy Richley Bristol Haematology and Oncology Centre 8 th June 2007

2. At Bristol we use the Radionics system for relocatable and fixed frame stereotactic radiotherapy. BRW frame Xknife planning system www.radiology.uiowa.edu/RadOnc/srsday-uIHC.html Bristol System Picture removed for confidentiality

3. Radionics System

4. 9 → 30 patients per year Aim for 20 multi-fraction relocatable and 10 single fraction fixed. Single Fraction: Metastases, Meningiomas, Acoustic Neuromas Multi-Fraction: Craniopharyngiomas, Pituitary Adenoma, Low Grade Glioma, Acoustic Neuromas The Patients

5. Current Established Practice Relocatable Frame – Pre-Treatment 11am Dental Hospital Appointment 12.30pm frame fitting – 1.5 hour slot. 2pm CT scan – 1 hour slot Image transfer, registration/fusion, outlining, planning, checking – Approx 4-5 hours QC – film test, dummy run

6. Current Established Practice Relocatable Frame - Treatment 8.30am start. Treat 3-4 patients daily. 1 hour slot for first patient and 30 min for subsequent patients.

7. Current Established Practice Fixed Frame 7.30 – 8am start Neurosurgeon attaches frame on ward 9am CT Patient back to ward Fusion, delineation of structures, planning / checking (~3 hrs) Treatment slot - 4pm film test, dummy run, room set-up Frame removed in treatment room Patient stays overnight on ward

8. The Team - Then and Now Original team members 2 oncologists 1 neurosurgeon 1 physicist and 1 technologist Now have a pool of additional team members including Radiographers (cascade training carried out by original team members).

9. Clinical Audit Aims Trust recommends all new techniques should be subject to clinical audit. This technique has defined indications, strict requirements and there is a need to assess that the appropriate treatment criteria and patient outcomes are being fulfilled.

10. Audit Criteria A) To ensure that the patient selection criteria for SRS/SRT are appropriate, as detailed in the local protocol (lesion size 6 months for SRS and > 2 yrs for SRT). B) To determine if the physical dose delivery is within the tolerance criteria as detailed in the local protocol. C) To determine whether the accuracy of the head-frame relocation lies within the specified tolerance ( 2mm ).

11. Standards A) Recommended good practice based on clinical experience (local consensus). B) Availability of well-conducted clinical studies but no randomised clinical trials on the topic of the recommendation. Ref: I.Rutten et al. Long Term follow-up reveals low toxicity of radiosurgery for vestibular schwannoma. Radiotherapy and Oncology 2007;82:83- 89. M.Fuss et al. FSRT for Acoustic Neuromas. International Journal of Radiation, Oncology, Biology and Physics 2000;48:1381-1387. C) Ref: Warrington J. Commissioning for Stereotaxis. Kirby M et al, editors. Report 94, Acceptance Testing and Commissioning of Linear Accelerators. York: YPS Publishing, 2006. pp 183-199, table 13.1.

12. Audit Methods Reviewed 40 patients treated between September 2002 and August 2005. 13 multi fraction treatment. 16 single fraction with a relocatable frame. 5 single fraction with a fixed frame. 6 patients cancelled

13. Audit Methods Reviewed patient notes and treatment plans. ( A,B ) Vector displacement spreadsheet designed by Simon Thomas (Burton et al (2002)). ( C ) Ref: K.E. Burton et al. Accuracy of a Relocatable Stereotactic Radiotherapy Head Frame Evaluated by use of a Depth Helmet. Clinical Oncology (2002) 14: 31–39

14. Results (A) 85% ( 29 out of 34 ) of all patients conformed to agreed lesion size criteria. 5 non-conformities (4.0cm, 4.02cm, 3.56cm, 3.7cm, 3.6cm – all SRT). All successfully treated.

15. Results (A) 88% (28 out of 32) conformed to agreed expected- survival criteria. NB – still waiting for 2 data points. 4 non conformities – all SRS. Confirms correct selection. Median Survival for SRS = 12.5 months. Min 3 months. Max 28 months. To date 100% SRT patients have achieved survival criteria.

16. Results (B) 100% of patients agreed to physical dose delivery.

17. Results (C) 94% (32 out of 34) of all treatments resulted in an accuracy of head frame relocation of <2mm Treatment TypeNumber of Patients Mean Displacement vector Multi fraction relocatable 13 92% (12) <2mm 100% (13) <2.5mm Single fraction relocatable 16 94% (15) <2mm 100% (16) <2.5mm Single fraction fixed 5 100% (5) <1mm

18. Depth Helmet Data Year (April-April) No. patients Mean Vector Length (mm) STDEV (mm) 200230.790.30 200341.580.55 200451.150.43 2005100.730.40 2006120.530.40 Year (April-April) No. patients Mean Vector length (mm) STDEV (mm) 200241.420.63 200310.86 200430.960.18 200581.060.44 2006150.920.24 User dependency of 0.51+/-0.28mm (35 data points) Multi fraction Single fraction 964 data points (Total 51 patients)

19. Outcomes 2 non-conformities for depth helmet measurements. Depth helmet results have revealed issues with velcro straps. User dependency of 0.51+/-0.28mm observed (35 data points).

20. Conclusions Tolerances on daily set-ups have been justified. Causes of uncertainty and user variability have been observed. Working practices have been refined. Have successfully treated lesions greater than the current 3.5cm limit – allow for clinician’s discretion within the protocol.

21. Acknowledgements Friends of Bristol Oncology Centre. Cathy Hall, Kirsten Hopkins, Hugh Newman, Tania McGreene, Karen Chalmers and the whole of the stereotactic team.