P40. Applying digital tomosynthesis (DTS) to diagnose lung cancer and follow up patients

Background: Lung cancer has the highest mortality rate among all cancer types regardless of sex. LDCT based screening had proven decrease the mortality of lung cancer. To keep these results but decrease the radiation dose and costs possible new or improved imaging techniques are actively investigating nowadays. In our study on a digital tomosynthesis (DTS) system that was produced in Hungary we tried to prove that DTS is suitable enough for some pulmonological exams. Also we were curious if DTS can replace LDCT in some cases.

Methods: A total of 60 patients were participated. Each of them had lung cancer disease and all of them had LDCT and DTS close in time. We were interested if it is possible to find on DTS images the lung nodules that are undetectable on conventional chest radiographs. We studied what are the smallest detectable lung nodules on the DTS images. We were also curious about if DTS can substitute LDCT to locate and measure extent of large airways stenosis.

Results: We found that the intrathoracic nodules, mediastinal and lymph node lesions can be found booth on the DTS slices and on the CT slices with almost the same rate. The detection of soft tissue lesions that were undetectable on conventional chest X-ray images seemed outstandingly good. Due to the coronal plane imaging the large airways, and especially the trachea and the main bronchus are very well visualized on the DTS slices. Incidentally vascular diseases and finer bone and pleural alteration were observed occasionally.

Conclusions: TThe DTS technique seems to be quite efficient for following intrathoracic lung cancer, while some structural bone lesions can also be detected easily. The method (especially using two views: PA and 30-degree LAT) seems to be quite efficient for detection and evaluation of large airways stenosis and also for indicating the possible palliative care. However the DTS does not replace the bronchoscopy, rather it complements it. In some cases DTS can replace CT scans resulting lower exposure. Specify the position of the DTS require further diagnostic studies in this area.

Keywords: Lung cancer; diagnosis; computer tomograhpy