Possible applications

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Cone-beam CT systems are used in a wide range of applications due to their simple structure, small size and consequently lower price and operating costs.
Although the spatial resolution can be achieved by these systems is very high, their human application is limited by the low soft tissue contrast, which is resulted by several reasons: the x-ray power usually smaller, therefore the image noise is higher, the dynamic range of the detector is 12-14 bits contrary to the 16bit used in third generation human systems and the scattered radiation is high due to the wide x-ray cone.
Obviously these systems are ideal for bone imaging with very high spatial resolution, therefore their main human application is the dental diagnostic imaging and implantation planning. The dental CBCT has very low dose to the patient and due to their small size they can be installed easily in almost any dental lab.
The low dose is also important in another application area that is the measurement of the attenuation map used to improve the image quality of SPECT and PET studies. Similarly to the SPECT and PET the data acquisition is done with slow rotation on a normally breathing patient. This is in contrary to third generation human CT, where the acquisition is done in deep inspiration, therefore the co-registration of the end results of different modalities (PET, SPECT and CBCT) is easier and more precise.
The cone-beam CT technology is almost exclusive in preclinical CT systems are used to image laboratory animals. Applications are focusing on high resolution imaging of objects having high contrast: studying bone and lung, tuberculosis, genetic disorders and studies using contrast agents to follow up the efficiency of tumour therapy. Respiratory and cardiac gated studies can be also performed by registering the required physiological signals.
Cone-beam CT systems are complimentary to the preclinical PET and SPECT systems. Following co-registration of the result images the localization and assessment of the findings visualized by the functional modalities are more precise. Similarly to the human application the CBCT can be used for attenuation correction to improve the PET and SPECT quantitative accuracy. Recently the high resolution CT images are used to improve the SPECT and PET spatial resolution using prior-based reconstruction algorithms and they can be used also to correct for the partial volume effect (PVE).

Figure 16 In vivo lung study in mouse. The high contrast objects (lung, ribs, vertebra and the subcutaneous fat) are well delineated on the image.

Figure 17. In vivo whole body mouse scan. Three dimensional visualization (Maximum Intensity Projection, MIP) of the skeleton of the mouse (size of the volume: 768×768×2560 voxel, voxel size: 39µm)

 
These systems are often used to image ex-vivo samples, like tissue samples, surgical excisions (e.g. tumour sections containing high contrast calcifications) and anatomical or pathological preparations.
Beside medical imaging cone-beam CTs are also used for industrial purpose. The main application is the non-destructive testing of the electronic components, when printed circuit boards are investigated with very high (<1µm) resolution in order to check their structure. The connectivity between different layers can be visualized in 3D, therefore these systems are not only useful for quality assurance purpose, but also for reverse engineering.

Figure 18 In vivo lung scan in mouse. Three dimensional visualization (volume rendering) of the lung