Portal de Periódicos da CAPES

Remote dosimetric auditing for intensity modulated radiotherapy: A pilot study

2017; Elsevier BV; Volume: 4; Linguagem: Inglês

10.1016/j.phro.2017.11.004

2405-6316

Narges Miri, Jöerg Lehmann, Kimberley Legge, Benjamin Zwan, Philip Vial, Peter B. Greer,

Radiation Therapy and Dosimetry

Background and PurposeElectronic portal imaging devices (EPIDs) can be used to reconstruct dose inside a virtual phantom. This work aims to study the feasibility of using this method for remote dosimetry auditing of clinical trials.Materials and MethodsSix centres participated in an intensity modulated radiotherapy (IMRT) pilot study of this new audit approach. Each centre produced a head and neck (HN) and post-prostatectomy (PP) trial plan and transferred the plans to virtual phantoms to calculate a reference dose distribution. They acquired in-air images of the treatment fields along with calibration images using their EPID. These data were sent to the central site where the images were converted to 2D field-by-field doses in a flat virtual water phantom and to 3D combined field doses in a cylindrical virtual phantom for comparison with corresponding reference dose distributions. Additional test images were used to assess the accuracy of the method when using different EPIDs.ResultsField-by-field 2D analysis yielded mean gamma pass-rates of 99.6% (±0.3%) and 99.6% (±0.6%) for HN and PP plans respectively (3%/3 mm, doses greater than 10% global max). 3D combined field analysis gave mean pass-rates of 97.9% (±2.6%) and 97.9% (±1.8%) for the HN and PP plans. Dosimetry tests revealed some field size limitations of the EPIDs.ConclusionsThe remote auditing methodology using EPIDs is feasible and potentially an inexpensive method.