A M Paton1, K E Chalmers, H Coomber, A L Cameron. 1. Radiotherapy Physics Unit, Bristol Haematology and Oncology Centre, University Hospitals Bristol NHS Foundation Trust, UK.
Abstract
OBJECTIVE: The aim of this study was to assess the impact of dose escalation on the proportion of patients requiring MR image-guided optimisation rather than standard Manchester-based CT-guided planning, and the level of escalation achievable. METHODS: 30 patients with cervical cancer treated with external beam radiotherapy and image-guided brachytherapy (IGBT) had MR images acquired at the first fraction of IGBT. Gross tumour volume and high-risk clinical target volume (HR CTV) were contoured and treatment plans retrospectively produced for a range of total 2-Gy equivalent (EQD2) prescription doses from 66 Gy(α/β=10) to 90 Gy(α/β=10) (HR CTV D90). Standard Manchester system-style plans were produced, prescribed to point A and then optimised where necessary with the aim of delivering at least the prescription dose to the HR CTV D90 while respecting organ-at-risk (OAR) tolerances. RESULTS: Increasing the total EQD2 from 66 Gy(α/β=10) to 90 Gy(α/β=10) increased the number of plans requiring optimisation from 13.3% to 90%. After optimisation, the number of plans achieving the prescription dose ranged from 93.3% (66 Gy(α/β=10)) to 63.3% (90 Gy(α/β=10)) with the mean ± standard deviation for HR CTV D90 EQD2 from 78.4 ± 12.4 Gy(α/β=10) (66 Gy(α/β=10)) to 94.1 ± 19.9 Gy(α/β=10) (90 Gy(α/β=10)). CONCLUSION: As doses are escalated, the need for non-standard optimised planning increases, while benefits in terms of increased target doses actually achieved diminish. The maximum achievable target dose is ultimately limited by proximity of OARs. ADVANCES IN KNOWLEDGE: This work represents a guide for other centres in determining the highest practicable prescription doses while considering patient throughput and maintaining acceptable OAR doses.
OBJECTIVE: The aim of this study was to assess the impact of dose escalation on the proportion of patients requiring MR image-guided optimisation rather than standard Manchester-based CT-guided planning, and the level of escalation achievable. METHODS: 30 patients with cervical cancer treated with external beam radiotherapy and image-guided brachytherapy (IGBT) had MR images acquired at the first fraction of IGBT. Gross tumour volume and high-risk clinical target volume (HR CTV) were contoured and treatment plans retrospectively produced for a range of total 2-Gy equivalent (EQD2) prescription doses from 66 Gy(α/β=10) to 90 Gy(α/β=10) (HR CTV D90). Standard Manchester system-style plans were produced, prescribed to point A and then optimised where necessary with the aim of delivering at least the prescription dose to the HR CTV D90 while respecting organ-at-risk (OAR) tolerances. RESULTS: Increasing the total EQD2 from 66 Gy(α/β=10) to 90 Gy(α/β=10) increased the number of plans requiring optimisation from 13.3% to 90%. After optimisation, the number of plans achieving the prescription dose ranged from 93.3% (66 Gy(α/β=10)) to 63.3% (90 Gy(α/β=10)) with the mean ± standard deviation for HR CTV D90 EQD2 from 78.4 ± 12.4 Gy(α/β=10) (66 Gy(α/β=10)) to 94.1 ± 19.9 Gy(α/β=10) (90 Gy(α/β=10)). CONCLUSION: As doses are escalated, the need for non-standard optimised planning increases, while benefits in terms of increased target doses actually achieved diminish. The maximum achievable target dose is ultimately limited by proximity of OARs. ADVANCES IN KNOWLEDGE: This work represents a guide for other centres in determining the highest practicable prescription doses while considering patient throughput and maintaining acceptable OAR doses.
Authors: Christian Kirisits; Stefan Lang; Johannes Dimopoulos; Karin Oechs; Dietmar Georg; Richard Pötter Journal: Radiother Oncol Date: 2006-11-28 Impact factor: 6.280
Authors: Richard Pötter; Christine Haie-Meder; Erik Van Limbergen; Isabelle Barillot; Marisol De Brabandere; Johannes Dimopoulos; Isabelle Dumas; Beth Erickson; Stefan Lang; An Nulens; Peter Petrow; Jason Rownd; Christian Kirisits Journal: Radiother Oncol Date: 2006-01-05 Impact factor: 6.280
Authors: Akila N Viswanathan; Sushil Beriwal; Jennifer F De Los Santos; D Jeffrey Demanes; David Gaffney; Jorgen Hansen; Ellen Jones; Christian Kirisits; Bruce Thomadsen; Beth Erickson Journal: Brachytherapy Date: 2012 Jan-Feb Impact factor: 2.362
Authors: H Ito; S Kutuki; I Nishiguchi; N Shigematsu; T Kuribayashi; M Uematsu; T Nakayama; W J Ka; K Takemasa; Y Ando Journal: Radiother Oncol Date: 1994-06 Impact factor: 6.280
Authors: Christine Haie-Meder; Richard Pötter; Erik Van Limbergen; Edith Briot; Marisol De Brabandere; Johannes Dimopoulos; Isabelle Dumas; Taran Paulsen Hellebust; Christian Kirisits; Stefan Lang; Sabine Muschitz; Juliana Nevinson; An Nulens; Peter Petrow; Natascha Wachter-Gerstner Journal: Radiother Oncol Date: 2005-03 Impact factor: 6.280
Authors: Christian Kirisits; Richard Pötter; Stefan Lang; Johannes Dimopoulos; Natascha Wachter-Gerstner; Dietmar Georg Journal: Int J Radiat Oncol Biol Phys Date: 2005-07-01 Impact factor: 7.038
Authors: C A Perez; S Fox; M A Lockett; P W Grigsby; H M Camel; A Galakatos; M S Kao; J Williamson Journal: Int J Radiat Oncol Biol Phys Date: 1991-09 Impact factor: 7.038
Authors: Richard Pötter; Johannes Dimopoulos; Petra Georg; Stefan Lang; Claudia Waldhäusl; Natascha Wachter-Gerstner; Hajo Weitmann; Alexander Reinthaller; Tomas Hendrik Knocke; Stefan Wachter; Christian Kirisits Journal: Radiother Oncol Date: 2007-05 Impact factor: 6.280
Authors: Bretislav Otahal; Martin Dolezel; Jakub Cvek; Ondrej Simetka; Jaroslav Klat; Lukas Knybel; Lukas Molenda; Eva Skacelikova; Ales Hlavka; David Feltl Journal: Rep Pract Oncol Radiother Date: 2014-05-01