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Statistical analysis on 2D array of ion chamber performance

Published online by Cambridge University Press:  12 January 2015

Akbar Anvari ,
Seyed Mahmoud Reza Aghamiri ,
Seyed Rabie Mahdavi  and
Parham Alaei
Akbar Anvari*
Affiliation:
Department of Radiation Medicine Engineering, Shahid Beheshti University, Tehran, Iran
Seyed Mahmoud Reza Aghamiri
Affiliation:
Department of Radiation Medicine Engineering, Shahid Beheshti University, Tehran, Iran
Seyed Rabie Mahdavi
Affiliation:
Department of Medical Physics, Iran University of Medical Sciences, Tehran, Iran
Parham Alaei
Affiliation:
Department of Radiation Oncology, University of Minnesota, Minneapolis, Minnesota, USA
*
Correspondence to: Akbar Anvari, Department of Radiation Medicine Engineering, Shahid Beheshti University, Tehran 19839-63113, Iran. Tel.: +98 21 29902541. E-mail: [email protected]
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Abstract

Purpose

In this work, dosimetric properties of the PTW Octavius detector in and out of the irradiation field have been evaluated. The 2D array of ion chambers has the potential to simplify the linear accelerator QA and pre-treatment verification.

Materials and methods

The evaluation was performed using customised written codes in Matlab and SPSS software for statistical analysis.

Results

Experiments indicate that the reproducibility and stability of the measurements were excellent; the detector showed the same signal with a maximum deviation of <0·5% in the short and long term. Comparisons of the ion chamber with the detector showed the same results with a maximum deviation of ~0·1%. As the detector response is linear with the dose, it can be used for the measurement at regions of high-dose gradient effectively. Logarithmic regression y=0·127 ln(x)+0·729 for detector signal and field size changes yielded a coefficient of determination of 0·997. The dose value decreases with increase in source-to-surface distance, which was modelled using a binomial regression with a coefficient of determination of 0·998 that agrees with the ionisation chamber measurement within 1%.

Conclusion

On the basis of the measurements and comparisons performed, this system is a reliable and accurate dosimeter for quality assurance in radiotherapy.

Keywords

ion chamber arraylinear acceleratorOctavius detector 729quality assurance
Type
Original Articles
Information
Journal of Radiotherapy in Practice , Volume 14 , Issue 2 , June 2015 , pp. 194 - 201
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Copyright
© Cambridge University Press 2015 

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References

1.Schreiner, L J. On the quality assurance and verification of modern radiation therapy treatment. J Med Phys 2011; 36 (4): 189–191.CrossRefGoogle ScholarPubMed
2.Pallotta, S, Marrazzo, L, Bucciolini, M. Design and implementation of a water phantom for IMRT, arc therapy, and tomotherapy dose distribution measurements. Med Phys 2007; 34: 3724–3731.CrossRefGoogle ScholarPubMed
3.Chandraraj, V, Stathakis, S, Manickam, Ret al. Comparison of four commercial devices for RapidArc and sliding window IMRT QA. J Appl Clin Med Phys 2011; 12 (2): 338–349.CrossRefGoogle ScholarPubMed
4.Simon, T A, Kozelka, J, Simon, W Eet al. Characterization of a multi-axis ion chamber array. Med Phys 2010; 37 (11): 6101–6111.CrossRefGoogle ScholarPubMed
5.Létourneau, D, Gulam, M, Yan, Det al. Evaluation of a 2D diode array for IMRT quality assurance. Radiother Oncol 2004; 70 (2): 199–206.CrossRefGoogle ScholarPubMed
6.Jursinic, P A, Sharma, R, Reuter, J. MapCHECK used for rotational IMRT measurements: step-and-shoot, tomotherapy, RapidArc. Med Phys 2010; 37: 2837–2846.CrossRefGoogle ScholarPubMed
7.Jursinic, P A, Nelms, B E. A 2-D diode array and analysis software for verification of intensity modulated radiation therapy delivery. Med Phys 2003; 30: 870–879.CrossRefGoogle ScholarPubMed
8.Herzen, J, Todorovic, M, Cremers, Fet al. Dosimetric evaluation of a 2D pixel ionization chamber for implementation in clinical routine. Phys Med Biol 2007; 52 (4): 1197.CrossRefGoogle ScholarPubMed
9.Li, J G, Yan, G, Liu, C. Comparison of two commercial detector arrays for IMRT quality assurance. J Appl Clin Med Phys 2009; 10 (2): 62–74.CrossRefGoogle ScholarPubMed
10.Wagner, D, Vorwerk, H. Two years experience with quality assurance protocol for patient related Rapid ARC treatment plan verification using a two dimensional ionization chamber array. Radiat Oncol 2011; 6 (21): 1–8.CrossRefGoogle ScholarPubMed
11.Alashrah, S, Kandaiya, S, Yong, Set al. Characterization of a 2D ionization chamber array for IMRT plan verification. Nucl Instrum Methods Phys Res A 2010; 619 (1): 181–185.CrossRefGoogle Scholar
12.Van Esch, A, Clermont, C, Devillers, Met al. On-line quality assurance of rotational radiotherapy treatment delivery by means of a 2D ion chamber array and the Octavius phantom. Med Phys 2007; 34: 3825–3837.CrossRefGoogle ScholarPubMed
13.Spezi, E, Angelini, A, Romani, Fet al. Characterization of a 2D ion chamber array for the verification of radiotherapy treatments. Phys Med Biol 2005; 50 (14): 3361–3373.CrossRefGoogle ScholarPubMed
14.Myers, P, Stathakis, S, Gutiérrez, A Net al. Evaluation of PTW seven29 for tomotherapy patient-specific quality assurance and comparison with ScandiDos Delta4. J Med Phys 2012; 37 (2): 72.Google ScholarPubMed
15.Van Esch, A, Basta, K, Evrard, Met al. The Octavius1500 2D ion chamber array and its associated phantoms: dosimetric characterization of a new prototype. Med Phys 2014; 41 (9): 091708.CrossRefGoogle ScholarPubMed
16.Anvari, A, Aghamiri, S, Mahdavi, Set al. Characterization of a 2D array for QA and pretreatment plan verification. Med Phys 2014; 41 (6): 236–237.CrossRefGoogle Scholar
17.Woulfe, P, Gillespie, S. Octavius 4D phantom implementation into patient specific quality assurance program. Phys Med Eur J Med Phys 2014; 30 (6): 719.Google Scholar
18.Markovic, M, Stathakis, S, Mavroidis, Pet al. Characterization of a two-dimensional liquid-filled ion chamber detector array used for verification of the treatments in radiotherapy. Med Phys 2014; 41 (5): 051704.CrossRefGoogle ScholarPubMed
19.Mezzenga, E, Cagni, E, Botti, Aet al. Pre-treatment and in-vivo dosimetry of helical tomotherapy treatment plans using the dosimetry check system. J Instrum 2014; 9 (4): C04039.CrossRefGoogle Scholar
20.Syamkumar, S, Padmanabhan, S, Sukumar, Pet al. Characterization of responses of 2D array seven29 detector and its combined use with Octavius phantom for the patient-specific quality assurance in rapidarc treatment delivery. Med Dosim 2012; 37 (1): 53–60.CrossRefGoogle ScholarPubMed
21.Stathakis, S, Myers, P, Esquivel, Cet al. Characterization of a novel 2D array dosimeter for patient-specific quality assurance with volumetric arc therapy. Med Phys 2013; 40 (7): 071731.CrossRefGoogle ScholarPubMed
22.Poppe, B, Stelljes, T, Looe, Het al. Performance parameters of a liquid filled ionization chamber array. Med Phys 2013; 40: 082106.CrossRefGoogle ScholarPubMed
23.McGarry, C K, O’Connell, B F, Grattan, M Wet al. Octavius 4D characterization for flattened and flattening filter free rotational deliveries. Med Phys 2013; 40 (9): 091707.CrossRefGoogle ScholarPubMed
24.Myers, P, Stathakis, S, Buckey, Cet al. VMAT monthly QA using two techniques: 2D ion chamber array with an isocentric gantry mount and an in vivo dosimetric device attached to gantry. J Radiother Pract 2014; 13 (2): 240–246.CrossRefGoogle Scholar
25.Andreo, P, Burns, D T, Hohlfeld, Ket al. Absorbed dose determination in external beam radiotherapy: an international code of practice for dosimetry based on standards of absorbed dose to water. Vienna (Austria): IAEA Technical Report Series, 2000: 398.Google Scholar