For the detection of pulmonary nodules, the performance of chest tomosynthesis is better, with increased sensitivity especially for nodules smaller than 9 mm, than that of chest radiography.

Chest tomosynthesis, which refers to the principle of collecting low-dose projections of the chest at different angles and using these projections to reconstruct section images of the chest, is an imaging technique recently introduced to health care. The main purpose of the present work was to determine the average effective dose to patients from clinical use of chest tomosynthesis. Exposure data for two chest radiography laboratories with tomosynthesis option (Definium 8000 with VolumeRAD option, GE Healthcare, Chalfont St. Giles, UK) were registered for 20 patients with a weight between 60 and 80 kg (average weight of 70.2 kg). The recorded data were used in the Monte Carlo program PCXMC 2.0 (STUK-Radiation and Nuclear Safety Authority, Helsinki, Finland) to determine the average effective dose for each projection. The effective dose for the chest tomosynthesis examination, including a scout view and the tomosynthesis acquisition, was finally obtained by adding the effective doses from all projections. Using the weighting factors given in ICRP 103, the average effective dose for the examination was found to be 0.13 mSv, whereas the average effective dose for the conventional two-view chest radiography examination was 0.05 mSv. A conversion factor of 0.26 mSv Gy(-1) cm(-2) was found suitable for determining the effective dose from a VolumeRAD chest tomosynthesis examination from the total registered kerma-area product. In conclusion, the effective dose to a standard-sized patient (170 cm/70 kg) from a VolumeRAD chest tomosynthesis examination is ~2 % of an average chest CT and only two to three times the effective dose from the conventional two-view chest radiography examination.

The development of investigation techniques, image processing, workstation monitors, analysing tools etc. within the field of radiology is vast, and the need for efficient tools in the evaluation and optimisation process of image and investigation quality is important. ViewDEX (Viewer for Digital Evaluation of X-ray images) is an image viewer and task manager suitable for research and optimisation tasks in medical imaging. ViewDEX is DICOM compatible and the features of the interface (tasks, image handling and functionality) are general and flexible. The configuration of a study and output (for example, answers given) can be edited in any text editor. ViewDEX is developed in Java and can run from any disc area connected to a computer. It is free to use for non-commercial purposes and can be downloaded from http://www.vgregion.se/sas/viewdex. In the present work, an evaluation of the efficiency of ViewDEX for receiver operating characteristic (ROC) studies, free-response ROC (FROC) studies and visual grading (VG) studies was conducted. For VG studies, the total scoring rate was dependent on the number of criteria per case. A scoring rate of approximately 150 cases h(-1) can be expected for a typical VG study using single images and five anatomical criteria. For ROC and FROC studies using clinical images, the scoring rate was approximately 100 cases h(-1) using single images and approximately 25 cases h(-1) using image stacks ( approximately 50 images case(-1)). In conclusion, ViewDEX is an efficient and easy-to-use software for observer performance studies.