Virtual Nodule Scanner

Objective

This open-source software is designed to simulate CT scan on a plumonary nodule to measure its volume. The objective is to study the influence of scanning parameters (slice interval, thickness, field-of-view) over the volume measurement of a lung nodule.

Simulating a CT scan

In order to isolate the factors, we simulate an ideal case, with an ideal nodule and an ideal scanner.

The ideal nodule

The nodule is a perfect isolated sphere, with homogeneous water intensity (0 HU) inside. It is surrounded by homogeneous lung intensity (-900 HU).

The ideal scanner

The scanner has no noise. The pixel value is sampled within a voxel cube and so partial volume effect is simulated. When slice thickness is set to 0, we are simulating extremely thin slice.

Volume Measurement

The nodule is segmented by simple thresholding at -450 HU (the median between the nodule and the lung). Then the volume is calculated by counting the segmented voxels, multiplying with the volume of a voxel.