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Rena Widita
Department of Physics, Faculty of Mathematics and Natural Sciences Institut Teknologi Bandung, Jl. Ganesa 10 Bandung 40132, Indonesia
Astronomy Computer Science & IT Earth & Planetary Sciences Electrical & Electronics Engineering Energy Engineering

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A Method for Beam Positions Determination in Image Reconstruction Rena Widita
Indonesian Journal of Physics Vol 17 No 3 (2006): Vol. 17 No. 3, July 2006
Publisher : Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (641.986 KB)

Abstract

From one treatment to the next, considerable effort is made to accurately position the patient consistent with the plan, but some variation is unavoidable. The target volume and the organ at risks may move within the patient and/or change shape during the treatment. Thus, it is important to be able to verify the success of the treatment by determining the position of patient and the dose deposited in the patient at each fraction. One possibility to achieve this would be to obtain an image while the patient is on the treatment couch. The aim of this study was to develop a method for determining beam positions to use to reconstruct an image for dose verification by collecting limited information while the patient is on the treatment couch. Two methods, image correlation and projection correlation, were developed and compared here. The effectiveness and practicality of each of these methods were compared. The results show that the projection correlation presents several advantages. It can be applied without any iterations, and it produces a fast algorithm. With more advanced image reconstruction software, this method could potentially be used in a clinical environment.
Projection Correlation Optimization using Simulated Annealing in CT Image Reconstruction Rena Widita
Indonesian Journal of Physics Vol 17 No 4 (2006): Vol. 17 No. 4, October 2006
Publisher : Institut Teknologi Bandung

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Abstract

Image reconstruction without analytical continuation is possible if and only if all projections cover entire object. In medical CT (Computed Tomography) applications, this condition is clearly not achievable. The new algorithm for image reconstruction using a few beam positions (projection correlation method) has been proved offer several advantages. . One drawback of using a few beam positions is a low quality image yielded. Thus, an objective function to rank the image quality is required to automate the decision process in determining the optimum beam positions. In this work, two optimization methods, gradient-descent method and simulated annealing, using projection correlation value as the objective function, were developed and compared to obtain the optimum beam positions. The effectiveness and practicality of each of these methods were compared. The results show that the simulated annealing presents superior results. This method could potentially be used in a clinical environment.
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