PURPOSE To analyze the reproducibility of patient specific IMRT QA results across five different clinical devices and one in-house detector by quantifying variations in the QA results from delivery-to-delivery (without re-setup, "redelivery") and variations when set-up is repeated ("re-setup"). METHODS Six patient plans were selected from among four treatment sites. Six methods of IMRT QA wer...

This study evaluated the feasibility of utilizing a 3D-printed anthropomorphic patient-specific head phantom for patient-specific quality assurance (QA) in intensity-modulated radiotherapy (IMRT). Contoured left and right head phantoms were converted from DICOM to STL format. Fused deposition modeling (FDM) was used to construct an anthropomorphic patient-specific head phantom with a 3D printer...

Emerging technologies such as four-dimensional computed tomography (4D CT) and implanted beacons are expected to allow clinicians to accurately model intrafraction motion and to quantitatively estimate internal target volumes (ITVs) for radiation therapy involving moving targets. In the case of intensity-modulated (IMRT) and stereotactic body radiation therapy (SBRT) delivery, clinicians must c...

There are many reports concerning patient-specific quality assurance (QA) for intensity-modulated radiation therapy (IMRT). However, reports about the statistical results of QA are lacking. Management methods for the results of the QA are needed, even though we have the ESTRO group recommendation that a tolerance limit of 1.96 standard deviation (SD) be established in each institution. The purp...

BACKGROUND This study was designed to compare the quality assurance (QA) results of four dosimetric tools used for intensity modulated radiation therapy (IMRT) and to suggest universal criteria for the passing rate in QA, irrespective of the dosimetric tool used. MATERIALS AND METHODS Thirty fields of IMRT plans from five patients were selected, followed by irradiation onto radiochromic film,...

PURPOSE A software program (MU-EPID) has been developed to perform patient specific IMRT pre-treatment QA verification using an electronic portal imaging device. METHODS The software converts measured images of intensity modulated beams delivered to an EPID, into fluence maps that can be imported in the treatment planning system. The dose can then be calculated in the patient anatomy and comp...

A patient-specific quality assurance (QA) test is conducted to verify the accuracy of dose delivery. It generally consists of three verification processes: the absolute point dose difference, the planar dose differences at each gantry angle, and the planar dose differences by 3D composite irradiation. However, this imposes a substantial workload on medical physicists. The objective of this stud...

PURPOSE To investigate various issues for clinical implementation of aSi EPID panels for IMRT/VMAT QA. METHODS Six linacs are used in our clinic for EPID-based plan QA; two Varian Truebeams, two Varian 2100 series, two Elekta Infiniti series. Multiple corrections must be accounted for in the calibration of each panel for dosimetric use. Varian aSi panels are calibrated with standard dark fiel...

BACKGROUND The purpose of this study is to implement an electronic method to perform and analyze intensity-modulated radiation therapy quality assurance (IMRT QA) using an aSi megavoltage electronic portal imaging device in a network comprised of independent treatment planning, record and verify (R&V), and delivery systems. METHODS A verification plan was generated in the treatment planning s...

PURPOSE A lower than ideal tolerance limit is used in intensity-modulated radiation therapy quality assurance (IMRT QA) with a 2D diode array due to passing rate fluctuations. The objective is to identify patterns in the passing rates to predict sources of uncertainty that can affect treatment delivery, for example, the need to re-calibrate the multileaf collimator when the passing rates start ...