Comparing step-and-shoot IMRT with dynamic helical tomotherapy IMRT plans for head-and-neck cancer

Journal Article · Mon Aug 01 00:00:00 EDT 2005 · International Journal of Radiation Oncology, Biology and Physics

DOI:https://doi.org/10.1016/j.ijrobp.2005.04.011· OSTI ID:20698516

Vulpen, Marco van ^[1]; Field, Colin ^[2]; Raaijmakers, Cornelis P.J. ^[1]; Parliament, Matthew B ^[3]; Terhaard, Chris H.J. ^[1]; MacKenzie, Marc A ^[2]; Scrimger, Rufus ^[3]; Lagendijk, Jan J.W. ^[1]; Fallone, B Gino ^[2]

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1. Department of Radiation Oncology, University Medical Centre Utrecht, Utrecht (Netherlands)
2. Division of Medical Physics, Cross Cancer Institute, Edmonton, AB (Canada)
3. Division of Radiation Oncology, Cross Cancer Institute, Edmonton, AB (Canada)

Purpose: The goal of this planning study was to compare step-and-shoot intensity-modulated radiotherapy (IMRT) plans with helical dynamic IMRT plans for oropharynx patients on the basis of dose distribution. Methods and Materials: Five patients with oropharynx cancer had been previously treated by step-and-shoot IMRT at University Medical Centre Utrecht, The Netherlands, applying five fields and approximately 60-90 segments. Inverse planning was carried out using Plato, version 2.6.2. For each patient, an inverse IMRT plan was also made using Tomotherapy Hi-Art System, version 2.0, and using the same targets and optimization goals. Statistical analysis was performed by a paired t test. Results: All tomotherapy plans compared favorably with the step-and-shoot plans regarding sparing of the organs at risk and keeping an equivalent target dose homogeneity. Tomotherapy plans in particular realized sharper dose gradients compared with the step-and-shoot plans. The mean dose to all parotid glands (n = 10) decreased on average 6.5 Gy (range, -4 to 14; p = 0.002). The theoretical reduction in normal tissue complication probabilities in favor of the tomotherapy plans depended on the parotid normal tissue complication probability model used (range, -3% to 32%). Conclusion: Helical tomotherapy IMRT plans realized sharper dose gradients compared with the clinically applied step-and shoot plans. They are expected to be able to reduce the parotid normal tissue complication probability further, keeping a similar target dose homogeneity.

• OSTI ID: 20698516
• Journal Information: International Journal of Radiation Oncology, Biology and Physics, Vol. 62, Issue 5; Other Information: DOI: 10.1016/j.ijrobp.2005.04.011; PII: S0360-3016(05)00691-7; Copyright (c) 2005 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0360-3016
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
CARCINOMAS
COMPUTERIZED TOMOGRAPHY
GLANDS
HEAD
HEALTH HAZARDS
NECK
NETHERLANDS
OPTIMIZATION
PATIENTS
PROBABILITY
RADIATION DOSE DISTRIBUTIONS
RADIATION DOSES
RADIOTHERAPY