Beckers, A.L.D. (Guus)

Gelsema, E.S.

Grashuis, J.L. (Jan)

Meer, F. (Frits) van der

Veenland, J.F. (Jifke)

J. F. Veenland

J. L. Grashuis

F. van der Meer

A. L. D. Beckers

E. S. Gelsema

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Estimation of fractal dimension in radiographs

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Estimation of fractal dimension in radiographs J. F. Veenland1, J. L. Grashuis1, F. van der Meer2, A. L. D. Beckers3 and E. S. Gelsema3Med. Phys. 23, 585 (1996); http://dx.doi.org/10.1118/1.597816AbstractIn the last decade, the fractal dimension has become a popular parameter to characterize image textures. Also in radiographs, various procedures have been used to estimate the fractal dimension. However, certain characteristics of the radiographic process, e.g., noise and blurring, interfere with the straightforward application of these estimation methods. In this study, the influence of quantum noise and image blur on several estimation methods was quantified by simulating the effect of quantum noise and the effect of modulation transfer functions, corresponding with different screen–film combinations, on computergeneratedfractalimages. The results are extrapolated to explain the effect of film‐grain noise on fractal dimension estimation. The effect of noise is that, irrespective of the noise source, the fractal dimension is overestimated, especially for lower fractal dimensions. On the other hand, blurring results in an underestimation of the dimensions. The effect of blurring is dependent on the estimation method used; the dimension estimates by the power spectrum method are lowered with a constant value, whereas the underestimation by the methods working in the spatial domain is dependent on the given dimension. The influence of the MTF and noise on fractal dimension estimation seriously limits the comparability of fractal dimensions estimated from radiographs which differ in noise content or MTF. Only when the power spectrum method is used, it is possible to correct for the influence of different MTFs of screen–film combinations. It is concluded that only when using the same object–focus distance, the same exposure conditions, the same digitizer at the same resolution, can fractal dimensions as estimated in radiographs be reliably compared.© 1996 American Association of Physicists in Medicine DOI: http://dx.doi.org/10.1118/1.597816Received 15 May 1995 Accepted 19 January 1996 Key TopicsFractalsRadiographyPage 1 of 2Estimation of fractal dimension in radiographs05-06-2015http://scitation.aip.org/content/aapm/journal/medphys/23/4/10.1118/1.597816Modulation transfer functionsMedical imagingQuantum effectsMost read this month Evaluation of treatment plans using target and normal tissue DVHs is no longer appropriateChristopher F. Njeh, Brent C. Parker and Colin G. OrtonTreatment planning evaluation and optimization should be biologically and not dose/volume basedJoseph O. Deasy, Charles S. Mayo and Colin G. OrtonTheoretical investigation of the design and performance of a dual energy (kV and MV) radiotherapy imagerLangechuan Liu, Larry E. Antonuk, Youcef El-Mohri, Qihua Zhao and Hao JiangMost cited this month Dosimetry of interstitial brachytherapy sources: Recommendations of the AAPM Radiation Therapy Committee Task Group No. 43Ravinder Nath, Lowell L. Anderson, Gary Luxton, Keith A. Weaver, Jeffrey F. Williamson and Ali S. MeigooniBEAM: A Monte Carlo code to simulate radiotherapy treatment unitsD. W. O. Rogers, B. A. Faddegon, G. X. Ding, C.‐M. Ma, J. We and T. R. MackieA technique for the quantitative evaluation of dose distributionsDaniel A. Low, William B. Harms, Sasa Mutic and James A. PurdyPage 2 of 2Estimation of fractal dimension in radiographs05-06-2015http://scitation.aip.org/content/aapm/journal/medphys/23/4/10.1118/1.597816

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Estimation of fractal dimension in radiographs

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