Keywords:
Lung, Radioprotection / Radiation dose, Digital radiography, Diagnostic procedure
Authors:
M. Mirzai, C. E. Meltzer, B. Gottfridsson, R. R. Norrlund, J. D. Vikgren, �. A. Johnsson, M. Båth, A. Svalkvist; Gothenburg/SE
DOI:
10.26044/ecr2019/C-3400
Aims and objectives
Chest tomosynthesis (CTS) is a diagnostic examination where several projection images of the chest are collected from different angles over a limited angular range to reconstruct section images of the patient [1].
Compared to conventional chest radiography (CXR),
CTS provides improved diagnostic information (Fig. 1) and has shown to improve detection of pulmonary nodules [2].
As tomosynthesis is performed with the same imaging system as CXR,
the financial cost is much lower and the patient throughput higher than for a corresponding computed tomography examination [3,
4].
Regarding the radiation dose from a chest tomosynthesis,
the estimated effective dose is 0.1 to 0.2 mSv [2,
5,
6] which is slightly higher than the radiation dose from a conventional chest radiography examination (typically 0.04 to 0.1 mSv),
but still significantly lower than the corresponding CT examination which is commonly higher than 3 mSv [7-9].
Using DTS as a problem-solver has the positive benefit that unnecessary CT examinations of patients with suspicious pathology detected on CXR are avoided,
as CTS has been shown to contribute to correct dismissal of suspicious pathology and correct characterization of lesions [4].
By avoiding unnecessary CT examinations the use of CT resources may be optimized [4] and the effective dose to the patient population will be reduced.
Optimization of image quality and radiation dose to the patient is important and previous studies have shown that nodule detection and accuracy in size measurements in DTS were unaffected by a dose reduction corresponding to 50% of the original dose [10,
11],
indicating that a reduction of the clinically used exposure during CTS examinations may be possible.
However,
up to date no study has been made with the purpose of assessing the effect of dose reduction on the overall image quality.
The purpose of the present study was to evaluate if a 50% reduction in effective dose affects the reproduction of important anatomical structures in chest tomosynthesis images.