For Publishers
DiscoveryMetadataPeer reviewHostingPublishing
For Researchers
JoinPublishReviewCollect
Register
Blog
About
Search
Advanced search
My ScienceOpen
Search
For Publishers
For Researchers
Blog
About
62
views
17
references
 Top references
cited by
2
    
0 reviews
 Review
0
comments
 Comment
0
recommends
+1 Recommend
0 collections
    0
    shares
      137
      similar
       All similar
      • Record: found
      • Abstract: found
      • Article: found
      Is Open Access

      Linear array measurements of enhanced dynamic wedge and treatment planning system (TPS) calculation for 15 MV photon beam and comparison with electronic portal imaging device (EPID) measurements

      research-article

      Read this article at

      ScienceOpenPublisherPMC
      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          Introduction.

          Enhanced dynamic wedges (EDW) are known to increase drastically the radiation therapy treatment efficiency. This paper has the aim to compare linear array measurements of EDW with the calculations of treatment planning system (TPS) and the electronic portal imaging device (EPID) for 15 MV photon energy.

          Materials and methods.

          The range of different field sizes and wedge angles (for 15 MV photon beam) were measured by the linear chamber array CA 24 in Blue water phantom. The measurement conditions were applied to the calculations of the commercial treatment planning system XIO CMS v.4.2.0 using convolution algorithm. EPID measurements were done on EPID-focus distance of 100 cm, and beam parameters being the same as for CA24 measurements.

          Results

          Both depth doses and profiles were measured. EDW linear array measurements of profiles to XIO CMS TPS calculation differ around 0.5%. Profiles in non-wedged direction and open field profiles practically do not differ. Percentage depth doses (PDDs) for all EDW measurements show the difference of not more than 0.2%, while the open field PDD is almost the same as EDW PDD. Wedge factors for 60 deg wedge angle were also examined, and the difference is up to 4%. EPID to linear array differs up to 5%.

          Conclusions

          The implementation of EDW in radiation therapy treatments provides clinicians with an effective tool for the conformal radiotherapy treatment planning. If modelling of EDW beam in TPS is done correctly, a very good agreement between measurements and calculation is obtained, but EPID cannot be used for reference measurements.

          Related collections

          Most cited references17

          • Record: found
          • Abstract: found
          • Article: not found

          Dosimetric properties of an amorphous silicon electronic portal imaging device for verification of dynamic intensity modulated radiation therapy.

          Sorina Popescu, Julia Greer (2003)
          Dosimetric properties of an amorphous silicon electronic portal imaging device (EPID) for verification of dynamic intensity modulated radiation therapy (IMRT) delivery were investigated. The EPID was utilized with continuous frame-averaging during the beam delivery. Properties studied included effect of buildup, dose linearity, field size response, sampling of rapid multileaf collimator (MLC) leaf speeds, response to dose-rate fluctuations, memory effect, and reproducibility. The dependence of response on EPID calibration and a dead time in image frame acquisition occurring every 64 frames were measured. EPID measurements were also compared to ion chamber and film for open and wedged static fields and IMRT fields. The EPID was linear with dose and dose rate, and response to MLC leaf speeds up to 2.5 cm s(-1) was found to be linear. A field size dependent response of up to 5% relative to dmax ion-chamber measurement was found. Reproducibility was within 0.8% (1 standard deviation) for an IMRT delivery recorded at intervals over a period of one month. The dead time in frame acquisition resulted in errors in the EPID that increased with leaf speed and were over 20% for a 1 cm leaf gap moving at 1.0 cm s(-1). The EPID measurements were also found to depend on the input beam profile utilized for EPID flood-field calibration. The EPID shows promise as a device for verification of IMRT, the major limitation currently being due to dead-time in frame acquisition.
          Article 0 comments Cited 42 times – based on 0 reviews     Review now
            Bookmark
            • Record: found
            • Abstract: found
            • Article: not found

            Quality assurance measurements of a-Si EPID performance.

            V Menon, Ron S. Sloboda (2003)
            The performance stability of a Varian aS500 amorphous silicon (a-Si) electronic portal imaging device (EPID) was monitored over an 18-month period using a variety of standard quality assurance (QA) tests. The tests were selected to provide ongoing information about image quality and dose response from the time of EPID acceptance into clinical service. To evaluate imaging performance, we made spatial resolution and contrast measurements using both PortalVision and QC-3V phantoms for 6- and 15-MV photon beams at repetition rates of 100, 300, and 400 MU/min in standard scanning mode. To assess operational stability for dosimetry applications, we measured central axis radiation response and beam pulse variability for the same image acquisition modes. Using the QC-3V phantom, values for the critical frequency of 0.435 +/- 0.005 lp/mm for 6 MV and 0.382 +/- 0.003 lp/mm for 15 MV were obtained. The contrast-to-noise ratio was found to be approximately 20% higher for the lower photon energy. Beam pulse variability remained within the tolerance of 3% set by the manufacturer. The central axis pixel response of the EPID remained constant within +/-1% over a 5-month period for the 6-MV beam, but fell approximately 4% over the same period for the 15-MV beam. The Varian aS500 EPID studied exhibited consistent image quality and a stable radiation response. These characteristics render it suitable for quantitative applications such as clinical dose measurement.
            Article 0 comments Cited 9 times – based on 0 reviews     Review now
              Bookmark
              • Record: found
              • Abstract: found
              • Article: not found

              Investigation of an amorphous silicon EPID for measurement and quality assurance of enhanced dynamic wedge.

              Chris Barnes, Julia Greer (2007)
              This work assessed the dosimetric performance of an amorphous silicon electronic portal imaging device (EPID) for measurement and quality assurance of enhanced dynamic wedge (EDW) profile and wedge factor. EPID measurements of EDW profiles were corrected for pixel sensitivity variation and spectral over-response relative to ion chamber and compared to ion-chamber and diode-array measurements. The dependence of EPID measurements on wedge direction and source to EPID distance was assessed. The long-term stability was investigated by weekly measurement of EDW profiles and wedge factors over a seven month interval. An empirical correction method was developed to improve EPID profile agreement with diode-array measurements. The EPID profiles differed from conventional measurements by up to 5%. Backscatter from the EPID housing was also found to affect measurements by up to 4%, resulting in changes in EPID measured profile with the direction of the moving jaw and source to EPID distance. EPID profile measurements varied by a maximum of 0.3% (1 SD) within the umbra, and wedge factors varied by 0.3% (1 SD) over the seven month interval. The correction function improved agreement between EPID and diode array to within 2% for all wedge angles and energies. Due to the ease of use and reproducibility of the EPID-measured EDW profiles the device is highly suited to regular measurement of EDW.
              Article 0 comments Cited 6 times – based on 0 reviews     Review now
                Bookmark
                All references

                Author and article information

                Journal
                Journal ID (nlm-ta): Radiol Oncol
                Journal ID (iso-abbrev): Radiol Oncol
                Journal ID (publisher-id): RADO
                Title: Radiology and Oncology
                Publisher: Versita, Warsaw
                ISSN (Print): 1318-2099
                ISSN (Electronic): 1581-3207
                Publication date Collection: September 2010
                Publication date (Electronic): 9 September 2010
                Publication date (Print): September 2010
                Volume: 44
                Issue: 3
                Pages: 199-206
                Affiliations
                [1 ] Department of Radiotherapy, Institute of Oncology Vojvodina, Sremska Kamenica, Serbia
                [2 ] Radiotherapy and Brachytherapy Planning Department, Comprehensive Cancer Centre, Maria Sklodowska Curie Memorial Institute, Gliwice, Poland
                Author notes
                Correspondence to: Borislava Petrovic MSc, Department of Radiotherapy, Institute of oncology Vojvodina, Institutski put 4, 21204 Sremska Kamenica. E-mail: nsbim@ 123456eunet.rs

                Disclosure: No potential conflicts of interest were disclosed.

                Article
                Publisher ID: rado-44-03-199
                DOI: 10.2478/v10019-010-0037-5
                PMC ID: 3423695
                PubMed ID: 22933916
                SO-VID: 0abfd335-133b-43a3-ac15-e9e23cda6da2
                Copyright © Copyright © by Association of Radiology & Oncology
                License:

                This article is an open-access article distributed under the terms and conditions of the Creative Commons Attribution license ( http://creativecommons.org/licenses/by/3.0/).

                History
                Date received : 8 March 2010
                Date accepted : 19 May 2010
                Categories
                Subject: Research Article

                ScienceOpen disciplines: Oncology & Radiotherapy
                Keywords: enhanced dynamic wedge,epid,linear array
                Data availability:
                ScienceOpen disciplines: Oncology & Radiotherapy
                Keywords: enhanced dynamic wedge, epid, linear array

                Comments

                Comment on this article