0000000000341655
AUTHOR
J Gimeno-olmos
SU-E-J-64: Evaluation of a Commercial EPID-Based in Vivo Dosimetric System in the Presence of Lung Tissue Heterogeneity
Purpose: To study the performance of Dosimetry Check (DC), an EPID-based dosimetry software, which allows performing transit dosimetry, in low density medium, by comparing calculations in-phantom, and analysing results for 15 lung patients. Methods: DC software (v.3.8, pencil beam-based algorithm) has been tested, for plans (Eclipse v.10.0 TPS) delivered in two Varian Clinac iX equipped with aS1000 EPIDs.In the CIRS lung phantom, comparisons between DC and Eclipse (Acuros) were performed for several plans: (1) four field box; (2) square field delivered in arc mode; (3) RapidArc lung patient plan medially centred; (4) RapidArc lung patient plan centred in one lung. Reference points analysed:…
SU-E-T-176: Commissiong and Initial Clinical Experience with Dosimetry Check, a Commercial Software for in Vivo Volumetric Dosimetry
Purpose: The aim of this work is to study the differences of reference point doses between the commercial EPID based dosimetry software Dosimetry Check (DC) and TPS to establish an accuracy level of the system, to evaluate its use in clinical routine and to obtain results for the first patients. Methods: We used DC v.3.8 (Math Resolutions), two Varian Clinac iX accelerators equipped with EPID aS1000 and Eclipse v.10.0 with AAA algorithm. Several plans with and without air gap were generated over the phantoms: MP1 Water Tank and Solid Octavius 4D (PTW). 5 head and neck, 3 lung and 4 prostate cases were selected for clinical evaluation. We compared the calculated dose at the isocenter and in …
SU-E-J-69: Evaluation of the Lens Dose On the Cone Beam IGRT Procedures
Purpose: With the establishment of the IGRT as a standard technique, the extra dose that is given to the patients should be taken into account. Furthermore, it has been a recent decrease of the dose threshold in the lens, reduced to 0.5 Gy (ICRP ref 4825-3093-1464 on 21st April, 2011).The purpose of this work was to evaluate the extra dose that the lens is receive due to the Cone-Beam (CBCT) location systems in Head-and-Neck treatments. Methods: The On-Board Imaging (OBI) v 1.5 of the two Varian accelerators, one Clinac iX and one True Beam, were used to obtain the dose that this OBI version give to the lens in the Head-and-Neck location treatments. All CBCT scans were acquired with the Sta…
SU-E-T-218: Octavius 4D: Commissioning and Clinical Implementation of a New Device for VMAT Verifications
Purpose: To commission a new device for pre‐treatment patient specific verification of VMAT plans, which is capable of reconstructing 3D dose with high resolution. Methods: Octavius 4D system (PTW) consists of an ion chamber array embedded in a cylindrical phantom which, assisted by an inclinometer, rotates synchronously with the gantry. For VMAT plans, it measures planar dose distributions as a function of gantry angle in order to compute the resulting 3D dose distribution. There are two options for the ion chamber array: Octavius 729 (general purpose) and Octavius 1000 SRS (small field size, high resolution). We have used three linacs: two Varian Clinac iX and one TrueBeam with MLC HD 120…
SU-E-T-343: Valencia Applicator Commissioning Using a Micro-Chamber Array
Purpose: In the commissioning and QA of surface isotope-based applicators, source-indexer distance (SID) has a great influence in the flatness, symmetry and output. To these purposes, methods described in the literature are the use of a special insert at the entrance of dwell chamber or radiochromic films. Here we present the experience with a micro-chamber array to perform the commissioning and QA of Valencia applicators. Methods: Valencia applicators have been used, the classic and the new extra-shielded version. A micro-chamber array has been employed, 1000 SRS (PTW), with 977 liquid filled, 2.3×2.3×0.5 mm3 sized ion chambers covering 11×11 cm2, which spacing is 2.5 mm in the central 5.5…