CHANGES IN REGIONAL BODY VOLUME AND GROSS TUMOR VOLUME AFFECT DOSE DISTRIBUTION DURING IMRT FOR HEAD AND NECK CANCER

• KAWAMORITA Ryu

  Department of Radiology, Tenri Hospital

• YAMADA Kazunari

  Hyogo Prefectural Tsukaguchi Hospital

• NAKAJIMA Toshifumi

  Department of Radiology, Tenri Hospital

• OKUNO Yoshishige

  Kobe City General Hospital

• OGURA Masakazu

  Department of Radiology, Tenri Hospital

Bibliographic Information

Other Title

• 頭頸部IMRT（Intensity Modulated Radiation Therapy）における 経時的な頭頸部領域体積の変化と線量分布への影響

Abstract

Purpose: Many patients experience tumor shrinkage and/or weight loss during the course of radiotherapy. Our aim is to evaluate the dosimetric changes in tumors and organs at risk (OAR) during the course of intensity-modulated radiation therapy (IMRT) for head and neck (H & N) cancer.<br>Method and materials: We compared the volume and dose parameters at the dose of 0 Gy and 40Gy in ten patients. By using a commercial inverse IMRT planning system, the 0 Gy IMRT plan for each patient was generated based on the original planning CT scan acquired before the start of treatment. The 40 Gy IMRT plan was generated by applying the beam configurations of the 0 Gy IMRT plan to the anatomy of the CT scan obtained at the doses of 40 Gy. The dose-volume histograms of the 0 Gy and 40 Gy IMRT plans were compared.<br>Results and Discussion: All patients had locally advanced, nonmetastatic diseases including 3 cervical esophagus, 3 oropharynx, 2 epipharynx and 2 unknown primary site. The regional body volume and body weight decreased in all patients. Gross tumor volume (GTV) decreased by 32% at most. Conformity index (C.I.) increased with decrease of GTV. Parotid gland volume decreased but the dose to 50% of the volume (D50) did not change. The maximum dose (Dmax.) to the spinal cord significantly increased in all patients (mean: 12%, p=0.0013). The 40 Gy IMRT plan is a hybrid plan without planning a new IMRT plan and should be generated several times during the course of IMRT for H & N cancer.

Journal

• The Journal of JASTRO

  The Journal of JASTRO 18 (4), 199-207, 2006

  Japanese Society for Therapeutic Radiology and Oncology

Keywords

• Head and neck cancer
• IMRT
• Dose distribution

Details

• CRID: 1390001204330846336
• NII Article ID: 10021282383
• NII Book ID: AN10123988
• DOI: 10.11182/jastro.18.199
• ISSN: 18819885
• ISSN: 10409564
• Web Site: https://search.jamas.or.jp/link/ui/2007337925
• Text Lang: ja
• Data Source:
  • JaLC
  • CiNii Articles
• Abstract License Flag: Disallowed