Author(s)

Janaka C. Marasinghe, Masaki Ohkubo, Hajime Kobayashi, Kohei Murao, Toru Matsumoto, Shusuke Sone, Shinichi Wada

Fujitsu Ltd., Tokyo, Japan.
Graduate School of Health Sciences, Niigata University, Niigata, Japan.
Graduate School of Health Sciences, Niigata University, Niigata, Japan Department of Radiography/Radiotherapy, Faculty of Allied Health Sciences, University of Peradeniya, Peradeniya, SriLanka.
Kensei Clinic, Chiba, Japan.
Nagano Health Promotion Corporation, Nagano, Japan.

Detection of small pulmonary nodules is the goal of lung cancer screening. Computer-aided detection (CAD) systems are recommended to use in lung cancer computed tomography (CT) screening to increase the accuracy of nodule detection. Size and density of lung nodules are primary factors in determining the risk of malignancy. Therefore, purpose of this study is to apply computer-simulated virtual nodules based on the point spread function (PSF) measured in same scanner (maintaining spatial resolution condition) to assess the CAD system performance dependence on nodule size and density. Virtual nodules with density differences between lung background and nodule density (ΔCT) values (200, 300 and 400 HU) and different sizes (4 to 8 mm) were generated and fused on clinical images. CAD detection was performed and free-response receiver operating characteristic (FROC) curves were obtained. Results show that both density and size of virtual nodules can affect detection efficiency. Detailed results are possible to use for quantitative analysis of a CAD system performance. This study suggests that PSF-based virtual nodules could be effectively used to assess the lung cancer CT screening CAD system performance dependence on nodule size and density.

Computed Tomography (CT), Point Spread Function (PSF), Lung Cancer Screening, Computer-Aided Detection (CAD), Virtual Nodule

Marasinghe, J. , Ohkubo, M. , Kobayashi, H. , Murao, K. , Matsumoto, T. , Sone, S. and Wada, S. (2014) Feasible Method to Assess the Performance of a Lung Cancer CT Screening CAD System in Clinical Practice: Dependence on Nodule Size and Density. International Journal of Medical Physics, Clinical Engineering and Radiation Oncology, 3, 107-116. doi: 10.4236/ijmpcero.2014.32016.