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Quantitative analysis of the image quality in megavoltage cone-beam computed tomography / 中华放射肿瘤学杂志
Chinese Journal of Radiation Oncology ; (6): 226-229, 2009.
Artículo en Chino | WPRIM | ID: wpr-395179
ABSTRACT
Objective To quantitatively analyze the image quality of megavoltage cone-beam CT (MVCBCT) under different scanning conditions to provide reference in clinical applications. Methods Si-emens ONCOR linear accelerator with MVCBCT was used to scan the phantom under different conditions. The image quality was evaluated in terms of image noise, uniformity, spatial resolution, contrast resolution, the number of Monitor Units(MUs) used in imaging,and the size of the reconstruction matrix. The comparison of the image quality between MVCBCT and conventional simulator CT was also analyzed. Results The image noise was decreased with the increase of the number of MUs. The uniformity index showed that the system u-niformity was weakly dependent on MU numbers or the size of the reconstruction matrix. Except for the ima-ges with 5 MUs,all other images had the spatial resolution of 0.4 lp/mm with a reconstruction matrix of 256 ×256. Better low contrast resolution was achieved by using more MUs. For typical pelvis and head-and-neck patients,the imaging dose at the center was 0.8 cGy/MU and 0.7 cGy/MU, respectively,and the maxi-mum dose was about 1.2 cGy/MU. For typical abdomen patients,the image maximum dose and center dose was 1.3 cGy/MU and 0.7 cGy/MU,respectively. Conclusions The image quality of MVCBCT is inferior to the conventional kilo-voltage CT. However,with the optimization of the parameters in imaging,we can a-chieve sufficient image contrast in the bone,air and some soft-tissue structures with low imaging dose to pa-tients. Such images can be used for IGRT.

Texto completo: Disponible Índice: WPRIM (Pacífico Occidental) Idioma: Chino Revista: Chinese Journal of Radiation Oncology Año: 2009 Tipo del documento: Artículo

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Texto completo: Disponible Índice: WPRIM (Pacífico Occidental) Idioma: Chino Revista: Chinese Journal of Radiation Oncology Año: 2009 Tipo del documento: Artículo