Dosimetric Comparison of Helical Tomotherapy and Linac-IMRT Treatment Plans for Head and Neck Cancer Patients

Xin Zhang, Jose Penagaricano, Eduardo G. Moros, Peter M. Corry, Yulong Yan, Vaneerat Ratanatharathorn

Research output: Contribution to journalArticle

11 Scopus citations

Abstract

The rapid development and clinical implementation of external beam radiation treatment technologies continues. The existence of various commercially available technologies for intensity-modulated radiation therapy (IMRT) has stimulated interest in exploring the differential potential advantage one may have compared with another. Two such technologies, Hi-Art Helical Tomotherapy (HT) and conventional medical linear accelerator-based IMRT (LIMRT) have been shown to be particularly suitable for the treatment of head and neck cancers. In this study, 23 patients who were diagnosed with stages 3 or 4 head and neck cancers, without evidence of distance metastatic disease, were treated in our clinic. Treatment plans were developed for all patients simultaneously on the HT planning station and on the Pinnacle treatment planning system for step-and-shoot IMRT. Patients were treated only on the HT unit, with the LIMRT plan serving as a backup in case the HT system might not be available. All plans were approved for clinical use by a physician. The prescription was that patients receive at least 95% of the planning target volume (PTV), which is 66 Gy at 2.2 Gy per fraction. Several dosimetric parameters were computed: PTV dose coverage; PTV volume conformity index; the normalized total dose (NTD), where doses were converted to 2 Gy per fraction to organs at risk (OAR); and PTV dose homogeneity. Both planning systems satisfied our clinic's PTV prescription requirements. The results suggest that HT plans had, in general, slightly better dosimetric characteristics, especially regarding PTV dose homogeneity and normal tissue sparing. However, for both techniques, doses to OAR were well below the currently accepted normal tissue tolerances. Consequently, factors other than the dosimetric parameters studied here may have to be considered when making a choice between IMRT techniques.

Original languageEnglish (US)
Pages (from-to)264-268
Number of pages5
JournalMedical Dosimetry
Volume35
Issue number4
DOIs
StatePublished - Nov 10 2010

Keywords

  • Dose coverage
  • Dose homogeneity
  • Dosimetry
  • Helical Tomotherapy
  • IMRT
  • Normal tissue dose tolerance
  • OAR
  • PTV

ASJC Scopus subject areas

  • Radiological and Ultrasound Technology
  • Oncology
  • Radiology Nuclear Medicine and imaging

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