Please use this identifier to cite or link to this item: http://hdl.handle.net/10397/28349
Title: Dosimetric evaluation of a three-phase adaptive radiotherapy for nasopharyngeal carcinoma using helical tomotherapy
Authors: Fung, WWK
Wu, VWC 
Teo, PML
Keywords: Adaptive radiotherapy Replanning
Helical tomotherapy
Nasopharyngeal carcinoma
Issue Date: 2012
Publisher: Elsevier Science Inc
Source: Medical dosimetry, 2012, v. 37, no. 1, p. 92-97 How to cite?
Journal: Medical Dosimetry 
Abstract: Adaptive radiotherapy (ART) has been introduced to correct the radiation-induced anatomic changes in head and neck cases during a treatment course. This study evaluated the potential dosimetric benefits of applying a 3-phase adaptive radiotherapy protocol in nasopharyngeal carcinoma (NPC) patients compared with the nonadaptive single-phase treatment protocol. Ten NPC patients previously treated with this 3-phase radiation protocol using Hi-Art Tomotherapy were recruited. Two new plans, PII-ART and PIII-ART, were generated based on the up-to-date computed tomography (CT) images and contours and were used for treatment in phase two (PII; after 25th fraction) and phase three (PIII; after 35th fraction), respectively. To simulate the situation of no replanning, 2 hybrid plans denoted as PII-NART and PIII-NART were generated using the original contours pasted on the PII- and PIII-CT sets by CT-CT fusion. Dosimetric comparisons were made between the NART plans and the corresponding ART plans. In both PII- and PIII-NART plans, the doses to 95% of all the target volumes (D 95) were increased with better dose uniformity, whereas the organs at risk (OARs) received higher doses compared with the corresponding ART plans. Without replanning, the total dose to 1% of brainstem and spinal cord (D 1) significantly increased 7.87 ± 7.26% and 10.69 ± 6.72%, respectively (P = 0.011 and 0.001, respectively), in which 3 patients would have these structures overdosed when compared with those with two replannings. The total maximum doses to the optic chiasm and pituitary gland and the mean doses to the left and right parotid glands were increased by 10.50 ± 10.51%, 8.59 ± 6.10%, 3.03 ± 4.48%, and 2.24 ± 3.11%, respectively (P = 0.014, 0.003, 0.053, and 0.046, respectively). The 3-phase radiotherapy protocol showed improved dosimetric results to the critical structures while keeping satisfactory target dose coverage, which demonstrated the advantages of ART in helical tomotherapy of NPC.
URI: http://hdl.handle.net/10397/28349
DOI: 10.1016/j.meddos.2011.01.006
Appears in Collections:Journal/Magazine Article

Access
View full-text via PolyU eLinks SFX Query
Show full item record

SCOPUSTM   
Citations

13
Last Week
0
Last month
1
Citations as of Aug 12, 2017

WEB OF SCIENCETM
Citations

11
Last Week
0
Last month
1
Citations as of Aug 12, 2017

Page view(s)

25
Last Week
1
Last month
Checked on Aug 13, 2017

Google ScholarTM

Check

Altmetric



Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.