1. IMRT in Cervix Cancer Tomas Kron, PhD Peter MacCallum Cancer Centre AUSTRALIA

4. Some anatomy

5. …is it constant? From Huh, SJ et al Radiother. Oncol. 71 (2004) 73 2 MRI T2 weighted images of the same patient 4 weeks and 35Gy apart

6. Some anatomy: lymph nodes

8. Cervix Plan … if inguinal lymph nodes need to be covered there is typically no advantage in adding lateral fields

9. Conventional treatment Mutic S et al IJROBP 55 (2003) 28 Region 2: 45Gy (para-aortic LN) Region 1: 45Gy + 5.4Gy EBT + brachytherapy boost

11. The impact of patient positioning on the adequate coverage of the uterus in the primary irradiation of cervical carcinoma: a prospective analysis using magnetic resonance imaging. Weiss E et al Radiother. Oncol. 63 (2002) 83 Results : Standard portals [ie 4 field box] did not completely cover the uterus in supine position in 7/21 (33%), in prone position with belly board in 7/21 (33%) and without belly board in 5/21 (24%). Insufficient uterine coverage was found only in the anteroposterior direction. The mean distance (± standard deviation) between the field borders of the lateral portals and the uterus was in supine position anteriorly 3.4 cm (±2.2 cm) and posteriorly 1.8 cm (±1.3 cm), in prone position with belly board anteriorly 2.2 cm (±2.7 cm) and posteriorly 2.6 cm (±1.6 cm), prone without belly board anteriorly 3.3 cm (±2.4 cm) and posteriorly 1.9 cm (±1.1 cm). The difference was statistically significant between supine and prone position with belly board and between prone position with and without belly board. Repeated MRI controls during therapy showed no significant changes compared to the MRIs at the beginning of therapy. Conclusions : The use of standard radiation fields results in a high percentage of geographical misfits. Three-dimensional treatment planning is a prerequisite for adequate uterus coverage.

17. Eg Tomotherapy planning station interface Everything of interest MUST be outlined… The system does not care about anything else.

18. Need for customisation? Courtesy A Fyles

19. … scope for customisation Collage courtesy S Van Dyk, K Narayan IMRT beneficial

20. What are the target outlines? IMRT difficult, if not impossible Prior to Txt After chemoradiation (40Gy) K Narayan and Quinn 2003

21. Prescription panel Three ways to guide the optimisation: 1. Precedence, 2. Importance, 3. Dose penalty

22. A ‘good’ dose calculation algorithm is required to avoid steering the optimization into a false minimum (Here: Superposition Convolution)

24. Planning as part of a network Issues: reliability, compatibility, security

27. IMRT to mimic Brachytherapy HDR brachy 7 field IMRT HDR brachy 7 field IMRT Schefter et al. Med Dosim 27 (2002) 177

30. Inter-fraction Organ Motion 7 July 03 21 July 03 14 July 03 5 Aug 03 Courtesy A Fyles

32. A Mundt and J Roeske: “ IMRT is a revolution in the treatment of cancer”

39. Dose Volume Histograms Comparison of three different treatment techniques (red, blue and green) in terms of dose to the target and a critical structure. Target dose Critical organ Important: Watch small hot and cold spots - DVH does not show where a particular dose is anatomically delivered to

41. Green Journal 1992: > 50 occasions of data transfer from one point to another for each patient!

45. Any questions?