Volumetric-modulated arc radiotherapy for carcinomas of the anal canal: A treatment planning comparison with fixed field IMRT

Comparative analysis of SmartArc‐based dual arc volumetric‐modulated arc radiotherapy (VMAT) versus intensity‐modulated radiotherapy (IMRT) for nasopharyngeal carcinoma

“…The delivery time was equal to $4.6\pm 0.7$ min per dual arc and was considerably less than the 7F‐IMRT delivery time. Studies on other VMAT approaches based on double RapidArc approaches ( 8 , 51 , 52 ) have shown delivery times ranging from 2.6 to 3.9 min that are faster than our results, whilst other improved IMAT approaches ( 53 , 54 ) have displayed delivery times ranging from 6.3 to 14 min for conventional linac‐based techniques. Here, we did not determine the fastest method, as previous reports were not performed under the same measurement conditions.…”

“…Here, we did not determine the fastest method, as previous reports were not performed under the same measurement conditions. (Note: a faster RapidArc measurement (2.6 min) was performed by Clivio et al ( 8 ) ) Plans were optimized selecting a maximum dose rate of 600 MU/min with constant gantry speed rotating at the maximum speed allowed (5.5°/s) with a total of 177 CPs per arc, couch angle set to 0° and collimator set to either 30° or 36° $(360°-\mathrm{X}\hspace{0.17em}\text{for}\hspace{0.17em}\text{the}\hspace{0.17em}\text{second}\hspace{0.17em}\text{arc})$, and managed all motions remotely in the reconfiguration state of the linac. VMAT plans created by the RapidArc algorithm can only be performed by the Varian machines.…”

“…( 8 – 13 ) The novel TPS SmartArc, developed by Philips Radiation Oncology Systems (Philips, Fitchburg, WI, USA) in collaboration with RaySearch Laboratories AB (Stockholm, Sweden) and which builds on the existing direct machine parameter optimization (DMPO) ( 14 ) functionality in ${\text{Pinnacle}}^3$, has recently become clinically and commercially available and can generate VMAT planning for both Elekta (Elekta Ltd., Crawley, UK) and Varian accelerators. ( 15 – 17 ) Another RaySearch‐based and linear accelerator (linac) vendor‐independent TPS, Oncentra MasterPlan v.3.3 (Nucletron BV, Veenendaal, The Netherlands), became clinically available in December 2009 and permits VMAT optimization for both linacs.…”

Application of AAPM TG 119 to volumetric arc therapy (VMAT)

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Conformity index (CI): (11) defined as the ratio between the volume covered by the prescribed isodose and target volume. For test cases prostate, head‐and‐neck, C‐shape, and Multi Target, prescription dose are 75.6 Gy, 50.4 Gy, 50 Gy and 50 Gy, respectively.

Homogeneity index (HI): (5) defined as the dose difference normalized to dose prescription $false({\mathrm{D}}_{\mathrm{pres}}false)$ between doses covering 5% ($D_5$) and 95% ($D_{95}$) of the PTV. …”

“…Homogeneity index (HI): (5) defined as the dose difference normalized to dose prescription $false({\mathrm{D}}_{\mathrm{pres}}false)$ between doses covering 5% ($D_5$) and 95% ($D_{95}$) of the PTV.…”