Journal of Medical Physics
ORIGINAL ARTICLE
Year
: 2013  |  Volume : 38  |  Issue : 2  |  Page : 74--81

Dosimetric comparison of different inhomogeneity correction algorithms for external photon beam dose calculations


Khadijeh Asnaashari1, Mohammad Rasa Golrokh Nodehi2, Seyyed Rabie Mahdavi3, Somaye Gholami3, Hamid Reza Khosravi4 
1 School of Allied Medical Sciences, Tehran, Iran
2 Department of Medical Radiation Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran
3 Department of Medical Physics, Tehran University of Medical Sciences, Tehran, Iran
4 National Radiation Protection, Iran Nuclear Regulatory Authority; Nuclear Sciences and Technology Research Institute, Atomic Energy Organization of Iran, Tehran, Iran

Correspondence Address:
Mohammad Rasa Golrokh Nodehi
Department of Medical Radiation Engineering, Science and Research Branch, Islamic Azad University, Tehran
Iran

Dose calculation algorithm is one of the main sources of uncertainty in the radiotherapy sequences. The aim of this study was to compare the accuracy of different inhomogeneity correction algorithms for external photon beam dose calculations. The methodology was based on International Atomic Energy Agency TEC-DOC 1583. The phantom was scanned in every center, using computed tomography and seven tests were planned on three-dimensional treatment planning systems (TPSs). The doses were measured with ion chambers and the deviation between measured and TPS calculated dose was reported. This methodology was tested in five different hospitals which were using six different algorithms/inhomogeneity correction methods implemented in different TPSs. The algorithms in this study were divided into two groups: Measurement-based algorithms (type (a)) and model-based algorithms (type (b)). In type (a) algorithms, we saw 7.6% and 11.3% deviations out of agreement criteria for low- and high-energy photons, respectively. While in type (b) algorithms, these values were 4.3% and 5.1%, respectively. As a general trend, the numbers of measurements with results outside the agreement criteria increase with the beam energy and decrease with advancement of TPS algorithms. More advanced algorithm would be preferable and therefore should be implanted in clinical practice, especially for calculation in inhomogeneous medias like lung and bone and for high-energy beams calculation at low depth points.


How to cite this article:
Asnaashari K, Nodehi MG, Mahdavi SR, Gholami S, Khosravi HR. Dosimetric comparison of different inhomogeneity correction algorithms for external photon beam dose calculations.J Med Phys 2013;38:74-81


How to cite this URL:
Asnaashari K, Nodehi MG, Mahdavi SR, Gholami S, Khosravi HR. Dosimetric comparison of different inhomogeneity correction algorithms for external photon beam dose calculations. J Med Phys [serial online] 2013 [cited 2021 Sep 27 ];38:74-81
Available from: https://www.jmp.org.in/article.asp?issn=0971-6203;year=2013;volume=38;issue=2;spage=74;epage=81;aulast=Asnaashari;type=0