What is Digital Tomosynthesis?

Digital tomosynthesis is primarily used in breast imaging, where it offers better detection rates than mammography, with little extra increase in radiation exposure. Because the image processing is digital, a series of slices at different depths and with different thicknesses can be reconstructed from the same acquisition, saving both time and radiation exposure. Tomosynthesis can be also used in place of a number of other radiographic imaging techniques including: chest, dental and orthopedic imaging and in localization of brachytherapy seeds.

Digital tomosynthesis is a technique of generating images of slices through the body using a general radiographic X-ray system with a direct digital radiography detector. This is accomplished by obtaining a large, representative number of low-dose acquisitions across a range of projection angles of the X-ray tube. Currently, tomosynthesis is an optional add-on for suitable direct digital radiographic systems (flat panel detectors). The additional software controls the movement of the X-ray tube and the reconstruction of the images.

The Basics of Digital Tomosynthesis

Digital tomosynthesis combines digital image capture and processing with simple tube and detector motion, as used in conventional radiographic tomography. Although there are some similarities to CT, it is a very different technique. In CT, the source and the detector make a complete 360-degree rotation around the patient, obtaining a complete set of data from which images may be reconstructed. In digital tomosynthesis, only small rotation angles (a few tens of degrees) with a small number of discrete exposures are used. This incomplete set of data can be digitally processed to yield images similar to conventional tomography, with a limited depth of field. However, because the image processing is digital, a series of slices at different depths and with different thicknesses can be reconstructed from the same acquisition, saving both time and radiation exposure.

How Digital Tomosynthesis Performs

Generally speaking, we can summarize the performance of digital tomosynthesis as follows:

Tomosynthesis can provide resolution of 0.2-0.4 mm in the x- and y- planes. In the z- plane the resolution is 5 mm for chest and 1 mm for breast.
Higher resolution in X- and y- planes than CT.
Dose-efficient compared to geometric tomography.

As mentioned before, tomosynthesis is a method for producing images of slices through the body using a general radiographic X-ray system with a digital detector. While the technique has been known for many years, only recently has the imaging system and computer hardware reached the required level of performance. The range of examinations that might be undertaken using tomosynthesis is currently under investigation. Work is ongoing in many applications, including chest, orthopedics, abdomen and breast. Tomosynthesis is an optional add-on to equipment that provides planar digital images.

CT produces image slices of the body, but it uses expensive, specialized equipment and is associated with high-radiation doses to the patient. Dual energy subtraction uses standard radiographic equipment and has shown some promise for chest imaging, although not all anatomical clutter is removed.

Major Geometric Approaches for Data Acquisition

There are three different geometric approaches for data acquisition:

1. The tube moves in a plane parallel to the detector plane and the detector may also move in its plane. This method is typically used in the chest and abdomen. Simplest reconstruction algorithm, maintains uniform magnification.

2. The tube and detector are fixed rigidly in relation to each other and move in tandem in a circular path around the patient. Used in cone-beam CT, in C-arm imagers and radiation oncology to verify patient position. Can provide excellent reconstructions, but with a more complicated algorithm.

3. The detector remains stationary, x-ray tube moves in an arc above the detector, used in breast tomosynthesis because of the ease of constructing a compact rotational gantry for the x-ray tube. Leads to variable magnification and different tube orientations and can therefore distort small structures, unless special care is taken in the back-projection process.

Some Tomosynthesis Applications

1. Mammography- tomosynthesis for breast imaging has been widely discussed in various studies and literature. While the technical principles remain the same as for general radiography, a higher performance mammography detector must be used, and dose levels will be of particular importance in potential breast screening applications.

2. Chest imaging- some research concludes that tomosynthesis showed improvement in image quality as compared with conventional tomography. An improvement of pulmonary module detection of tomosynthesis in recent years was noticed. One paper suggests that three times more pulmonary modules were found by tomosynthesis in comparison with the planar x-ray.

3. Orthopedics- it was demonstrated that tomosynthesis had potential for imaging arthritis changes in the hands. Also, some improvement was found in the ability to visualize hip prostheses with tomosynthesis, and it was noted that tomosynthesis can avoid streak artifacts from metal objects, which can cause problems for CT images.

As images are clearer and diagnoses more accurate using digital tomosynthesis, many imaging departments are using it for many applications. If you are interested in purchasing this type of equipment, a sensible place to look is MedWOW, where you can find a large selection of all sorts of radiography and imaging equipment and parts from sellers all over the world, bringing you more competitive prices and services.

When searching on MedWOW for radiographic X-ray systems, digital mammography and direct digital radiography detectors, needed for tomosynthesis; go to MedWOW's all-inclusive and intuitive search engine, which allows you to find the exact used tomosynthesis equipment that you are searching for, using filtering options such as: manufacturer, model, price range, year manufactured, location and many other filters.

New and used imaging equipment on MedWOW even includes details which may have a significant impact on the medical facility's needs, such as: detector type and size, Ma range and more. The tomosynthesis-related imaging systems posted on MedWOW include various models from numerous manufacturers. For example, there is currently a wide range including: GE Healthcare, Philips, Hologic, Fischer, Lorad, Toshiba and others, with even more being added all the time, so you are sure to find exactly the make and model exactly suited to your needs.

Another alternative is to post a buying request for the type of digital tomosynthesis you are looking for, by filling out a form and giving as much information as possible. MedWOW attracts sellers from all over the world and so you will likely be sent a few quotes for your selected digital tomosynthesis.