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The dosimetric comparison between tomotherapy and RapidArc in normal tissue sparing for nasopharyngeal carcinoma

Published online by Cambridge University Press:  14 November 2019

Pubade Kaewpruk Open the ORCID record for Pubade Kaewpruk [Opens in a new window] ,
Somvilai Chakrabandhu ,
Somsak Wanwilairat Open the ORCID record for Somsak Wanwilairat [Opens in a new window]  and
Wannapha Nobnop Open the ORCID record for Wannapha Nobnop [Opens in a new window]
Pubade Kaewpruk
Affiliation:
Department of Radiology, Division of Radiation Oncology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand Graduate School, Chiang Mai University, Chiang Mai, Thailand
Somvilai Chakrabandhu*
Affiliation:
Department of Radiology, Division of Radiation Oncology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
Somsak Wanwilairat
Affiliation:
Department of Radiology, Division of Radiation Oncology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
Wannapha Nobnop
Affiliation:
Department of Radiology, Division of Radiation Oncology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
*
Author for Correspondence: Somvilai Chakrabandhu, Department of Radiology, Division of Radiation Oncology, Faculty of Medicine, Chiang Mai University, 110 Intavaroros Rd., Sriphum, Chiang Mai 50200, Thailand. Tel: 66 53935456. Fax: 66 53935491. E-mail: somjee@hotmail.com
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Abstract

Purpose:

To compare the dosimetric results regarding the sparing effect on normal tissue between RapidArc (RA) and helical tomotherapy (HT) plans for nasopharyngeal carcinoma (NPC) patients in cases of the equal target dose controls utilising two techniques.

Materials and Methods:

Thirteen NPC patients treated with HT were replanned using the Varian Eclipse treatment planning system (TPS) for the RA plan. The target dose of the RA plan was optimised equally to the HT plan in terms of target coverage, dose conformity (CI) and dose homogeneity (HI) for assessing the normal tissue sparing between two techniques. All dose–volume parameters monitor units (MUs) and delivery time were also investigated.

Results:

All dosimetric parameter comparisons of organs-at-risk (OARs) between the RA and HT plans were not significantly different for brain stem, spinal cord and cochlea. However, the RA plan showed a significantly lower dose to the left parotid gland. The mean and median dose were significantly lower in the RA plan versus the HT plan by p-value 0·005 and 0·039, respectively. The MUs and delivery time were also significantly lower in the RA plan with a p-value of 0·00.

Conclusions:

With the same planning target volume coverage, homogeneity and conformity, almost all of RA and HT treatment planning met the planning goal for normal tissue sparing. There were no significant differences between the two techniques except in the left parotid gland. The RA plans were superior to HT plans by effectively reducing the MUs and treatment time.

Keywords

Dosimetric comparisonNasopharyngeal CarcinomaTomotherapyTreatment planningRapidArc
Type
Original Article
Information
Journal of Radiotherapy in Practice , Volume 19 , Issue 3 , September 2020 , pp. 237 - 241
Copyright
© Cambridge University Press 2019

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