Abstract
The purpose of this study was to investigate the potential benefits of using triple‐arc volumetric‐intensity modulated arc radiotherapy (RapidArc (RA)) for the treatment of early‐stage nasopharyngeal carcinoma (NPC). A comprehensive evaluation was performed including plan quality, integral doses, and peripheral doses. Twenty cases of stage I or II NPC were selected for this study. Nine‐field sliding window IMRT, double‐arc, and triple‐arc RA treatment plans were compared with respect to target coverage, dose conformity, critical organ sparing, and integral doses. Measurement of peripheral doses was performed using thermoluminescent dosimeters in an anthropomorphic phantom. While similar conformity and target coverage were achieved by the three types of plans, triple‐arc RA produced better sparing of parotid glands and spinal cord than double‐arc RA or IMRT. Double‐arc RA plans produced slightly inferior parotid sparing and dose homogeneity than the other two delivery methods. The monitor units (MU) required for triple‐arc were about 50% less than those of IMRT plans, while there was no significant difference in the required MUs between triple‐arc and double‐arc RA plans. The peripheral dose in triple‐arc RA was found to be 50% less compared to IMRT near abdominal and pelvic region. Triple‐arc RA improves both the plan quality and treatment efficiency compared with IMRT for the treatment of early stage NPC. It has become the preferred choice of treatment delivery method for early stage NPC at our center.PACS numbers: 87.53.Bn, 87.55.D, 87.55.de, 87.55.dk, 87.56.ng
Highlights
190 Kan et al: Triple-arc for early stage nasopharyngeal carcinoma (NPC) radiotherapy with multileaf collimator (MLC) that changes the shape of the treatment field dynamically while the gantry rotates around the patient.[9]Comparison between volumetric-modulated arc radiotherapy (VMAT) dose distribution in head and neck cancer and those obtained by conventional intensity-modulated radiotherapy with static gantry (IMRT) techniques have been reported by several investigators.[2,3,4,5,6,7,8] The head and neck cases chosen by previous investigators mostly involved a mixture of various sites including NP region, oropharynx, larynx, and hypopharynx
Our investigation focused merely on early-stage NPC proved that the use of triple-arc RA produced comparable dose conformity and target dose homogeneity, as well as better sparing of the parotid glands, spinal cord, planning organ at risk volume (PRV) spinal cord, and PRV brain stem compared with nine-field sliding window IMRT
The number of monitor units (MU) and delivery time were both reduced by approximately 50% when triple-arc RA was employed, as compared to the sliding window IMRT
Summary
190 Kan et al: Triple-arc for early stage NPC radiotherapy with MLC that changes the shape of the treatment field dynamically while the gantry rotates around the patient.[9]Comparison between VMAT dose distribution in head and neck cancer and those obtained by conventional IMRT techniques have been reported by several investigators.[2,3,4,5,6,7,8] The head and neck cases chosen by previous investigators mostly involved a mixture of various sites including NP region, oropharynx, larynx, and hypopharynx. Lee et al[7] have done a pioneer investigation comparing between SmartArc-based VMAT and seven-field step-and-shoot IMRT for NPC. They concluded that dual-arc VMAT produced similar target coverage and organ sparing as seven-field step-and-shoot IMRT with faster delivery time. Extensive comparison among double-arc, triple-arc RapidArc, and sliding window IMRT for NPC cases has not been reported. NPC cases with different staging involve different levels of complexity Taking into account both early and advanced stage diseases together in the same evaluation might produce mixed results. Our current study compared both plan quality and treatment efficiency among double-arc, triple-arc RapidArc, and nine-field sliding window IMRT, focusing on early stage NPC
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
