Ji Hyun Koo MD, Presenter: Nothing to Disclose

Myung Jin Chung MD, Abstract Co-Author: Nothing to Disclose

Hye Na Jung MD, Abstract Co-Author: Nothing to Disclose

Hee Cheol Kim MD, Abstract Co-Author: Nothing to Disclose

Kyung Soo Lee MD, Abstract Co-Author: Nothing to Disclose

Ju Won Lee MD, Abstract Co-Author: Nothing to Disclose

Hye Sun Hwang MD, Abstract Co-Author: Nothing to Disclose

Tae Yeon Jeon MD, Abstract Co-Author: Nothing to Disclose

00030490-DMT et al, Abstract Co-Author: Nothing to Disclose

The aim of this study was to evaluate the performance of digital tomosynthesis (DTS) of the chest with very low dose for detection of lung nodules in patients with colon cancer

DTS was performed with a commercial CsI/a-Si flat panel detector system. We tuned the parameters of DTS and established lesser dose condition for chest scan. The entrance surface dose of this protocol was 0.31 mGy, and effective dose was 0.05 mSv on RANDO phantom. Routine single phase chest CT in our instituted was 5.8 mSv on same phantom. Low dose DTS was performed in 146 patients with colon cancer. Synthetic coronal planar images were reconstructed with 5 mm interval. Reconstructed images fully covered from anterior skin to back of chest. All of 146 patients underwent chest CT scans within a week from DTS. Two radiologists reviewed the chest CT with a consensus and recorded about the presence of pulmonary nodules as the reference. Another two radiologists blinded from the CT results observed the images of DTS and recorded the presence of pulmonary nodules on DTS. The status of all lung nodules was assessed either histologically or by follow-up over than 6 months. Then, we classified the nodules into metastasis, uncertain, and benign. We analyzed the results statistically.

The 232 nodules were found in 146 patients. Among them, 71 proven metastases and 113 benign nodules were included, 24 nodules were uncertain. Observers detected 76% of lung nodules (Ob1, 74%, Ob2, 78%). Observers detected 81% of proven metastases (Ob1, 78%, Ob2, 83%). Among 232 nodules, 190 nodules were bigger than 4mm in diameter on CT axial image. Observers detected 80% of lung nodules bigger than 4 mm. There were 14 nodules which showed ground glass opacity (GGO) on CT images. Observers detected only 14% of these GGO nodules. Inter-observer agreement between two observers was excellent (k = .828, kappa statistic analysis).

Digital tomosynthesis of the chest gave minimal radiation to the patient compared to chest CT. In spite of very low radiation dose, DTS is a sensitive modality comparable to chest CT to detect lung nodules, especially metastatic lung nodules in patient with colon cancer.

DTS can be a safe and cheap alternate of chest CT for screening the lung metastasis. It can cover the interim period between CT follow up intervals.

Koo, J, Chung, M, Jung, H, Kim, H, Lee, K, Lee, J, Hwang, H, Jeon, T, et al, 0, Low Dose Digital Tomosynthesis of the Chest in Patients with Colon Cancer: Usefulness for Screening Lung Metastasis.  Radiological Society of North America 2009 Scientific Assembly and Annual Meeting, November 29 - December 4, 2009 ,Chicago IL. http://archive.rsna.org/2009/8013689.html