Aims and objectives
Computed tomography (CT) is the most important source of medical radiation exposure and thus dose reduction has become a crucial topic.
In the last years strategies to optimize CT procedures have been developed: a successful approach is obtained by the introduction and the improvement of iterative reconstruction algorithms (IR).
This iterative reconstruction methods,
in opposition to filtered back projection,
incorporate physical models and allow to perform CT studies at lowed doses. In this...
Methods and materials
In this study Catphan 600 was used as a test object.
This phantom is dedicated to image quality assurance in computed tomography and it’s composite of several modules.
We employed the CTP486 homogeneous water equivalent module to evaluate noise properties and the low-contrast CTP515 module to evaluate CNR.
This second module is composed of supra and subslice contrast targets with different diameters ranging from 2 to 25 mm and nominal contrast of 0.3%,
0.5% and 1%. Images of the 2 modules of...
Noise Figure 1 shows noise varying with tube potential for FBP algorithm and ASIR- V with different levels of reconstruction (40% - 60%).
Noise level decreases with the increase of level of reconstruction. Figure 2 shows noise in correlation with tube loading,
and Figure 3 Noise versus Pitch.
As it can be seen,
noise decrease with the increasing of tube voltage while on the other hand noise increased while increasing the pitch value. CNR Regarding to CNR value,as shown in fig.
4 we found an...
Compared to the standard FBP algorithm the ASir-V gives an improvement of image quality and allows to acquire images at a lower dose with the same CNR as the standard protocol.
Origgi – “New adaptive statistical iterative reconstruction AsiR – V: Assesment of noise performance in comparison to ASiR” – J Appl Clin Med Ohys (2018; 19:2:275-286) Barca P,
Caramella D – “Evaluation of the imaging properties of a CT scanner with the adaptive statistical iterative reconstruction algorithm – Noise contrast and spatial resolution properties of CT images reconstructed at Different blending levels.” – proceedings of the 10 th International...