Feasibility of novel in vivo EPID dosimetry system for linear accelerator quality control tests

  • Fatih BiltekinEmail author
  • Yagiz Yedekci
  • Gokhan Ozyigit
Scientific Paper


The main aim was to validate the capability of a novel EPID-based in vivo dosimetry system for machine-specific quality control (QC) tests. In current study, two sets of measurements were performed in Elekta Versa HD linear accelerator using novel iViewDose™ in vivo dosimetry software. In the first part, measurements were carried out to evaluate the feasibility of novel in vivo system for daily dosimetric QC tests including output constancy, percentage depth dose (PDD) and beam profile measurements. In addition to daily QC tests, measured output factor as a function of field size, leaf transmission and tongue and groove effect were compared with calculated TPS data. In the second part of the measurements, detection capability of iViewDose software for basic mechanical QC tests were investigated for different setup conditions. In dosimetric QC tests, measured output factor with changing field size, PDD, beam profile and leaf transmission factors were found to be compatible with calculated TPS data. Additionally, the EPID-based system was capable to detect given dose calibration errors of 1% with ± 0.02% deviation. In mechanical QC tests, it was found that iViewDose software was sensitive for catching errors in collimator rotation (≥ 1°), changes in phantom thickness (≥ 1 cm) and major differences in irradiated field size down to 1 mm. In conclusion, iViewDose was proved to be as useful EPID-based software for daily monitoring of linear accelerator beam parameters and it provides extra safety net to prevent machine based radiation incidents.


Quality control EPID Linear accelerator 







Dose reference point


Beam’s eye view


Computed tomography


Dose differences


Digital imaging and communications in medicine


Distance to agreement


Electronic portal imaging device


Intensity modulated radiotherapy


Multileaf collimator


Monitor unit


Percentage depth dose




Stereotactic body radiation therapy


Stereotactic radiosurgery/radiotherapy


Source to surface distance


Treatment planning system


Quality control


Volumetric modulated arc therapy


Compliance with ethical standards

Conflict of interest

There is no conflict of interest.

Ethical approval

This article does not contain any studies with human participants or animals performed by any of the authors.


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Copyright information

© Australasian College of Physical Scientists and Engineers in Medicine 2019

Authors and Affiliations

  1. 1.Department of Radiation Oncology, Faculty of MedicineHacettepe UniversityAnkaraTurkey

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