Dosimetric comparison between RapidArc and HyperArc techniques in salvage stereotactic body radiation therapy for recurrent nasopharyngeal carcinoma

Abstract

Background: To evaluate dosimetric differences of salvage irradiations using two commercially available volumetric modulated arc therapy (VMAT) stereotactic body radiation therapy (SBRT) techniques: RapidArc (RA) and HyperArc (HA), for recurrent nasopharyngeal carcinoma (NPC) after initial radiation therapy. Methods: Ten patients with recurrent NPC status previously treated with radiation therapy were considered suitable candidates for salvage SBRT using VMAT approach. Two separate treatment plans were created with HA and RA techniques for each case, with dosimetric outcomes compared with respect to tumor target coverage and organs-atrisk (OARs) sparing. Furthermore, the cumulative radiobiological effects to the relevant OARs from the original radiotherapy to the respective salvage SBRT plans were analyzed in terms of biologically effective dose (BED). Results: Treatment with HA exhibited similar target dose coverage as with RA, while delivering a higher mean dose to the targets. Using RA technique, the mean maximal doses to optic apparatus and the mean brain dose were reduced by 1 to 1.5 Gy, comparing to HA technique. The conformity index, gradient radius, and intermediate dose spillage in HA plans were significantly better than those in RA. With HA technique, the volume of brain receiving 12 Gy or more was reduced by 44%, comparing to RA technique. The cumulative BEDs to spinal cord and optic apparatus with RA technique were 1 to 2 Gy 3 less than those with HA. HA technique significantly reduced the volume within body that received more than 100 Gy. Conclusions: With better dose distribution than RA while maintaining sufficient target dose coverage, HA represents an attractive salvage SBRT technique for recurrent NPC.

The new SRS/FSRT technique HyperArc for benign brain lesions: a dosimetric analysis

“…Another distinguishing advantage of HA-S is consistently reducing the radiation dose to multiple OARs, including dose to the brainstem, brain V24, V12, V5, eyes, and lens, comparing to coplanar RA. Similar findings have been demonstrated that HA has some advantage over RA for intracranial brain metastasis treatment 17 , 19 , 22 , 23 and extracranial 41 treatment.…”

Organ-at-risk sparing with dynamic trajectory radiotherapy for head and neck cancer: comparison with volumetric arc therapy on a publicly available library of cases

“…Despite encouraging dosimetric quality of DTRT plans and the promise of deliverability on standard C-arm linacs [6,12], it remains a research topic for HN radiotherapy and is not yet clinically available. Nasopharyngeal and cranial tumours have often been investigated owing to the large collision-free space [7,11,12] with statictable non-coplanar solutions already commercially available on C-arm linacs [13,14]. Large HN target volumes are often associated with high rates of toxicity and could benefit from DTRT but these have a more caudal isocenter.…”

Effect of Stereotactic Body Radiation Therapy Combined with Thermoplastic Fixation on Set-Up Errors in Breast Cancer Patients Undergoing Radiotherapy

“…According to statistics, on average, one out of 17 women worldwide develops BC in their whole life, and the majority of the patients with breast malignant tumor are the ones with hormone receptor-positive breast cancer, which account for about 65% [ 6 ]. Ho et al [ 7 ] have stated that BC is the most prevalent malignant tumor among women, and its incidence, which has been increasing in recent years, accounts for 14% of all malignant tumors in the female body. According to pertinent literature, the BC incidence among Asian women increased by approximately 1.7% per year from 2006 and 2015, so it is urgent to provide effective treatment for BC patients [ 8 ].…”