Purpose: X-ray luminescence computed tomography (XLCT) is an emerging x-ray molecular imaging modality. Pencil beam XLCT imaging provides superior spatial resolution than other imaging geometries like sheet beam and cone beam geometries. However, the pencil beam XLCT suffers from long scan times resulting in concerns over dose, which discourages the use of pencil beam x-ray sources in XLCT imaging.
Methods: To investigate the dose deposited by pencil beam x-ray in XLCT imaging, we used the Monte Carlo simulation platform, GATE (Geant4 Application for Tomographic Emission) to estimate the dose of one angular projection scan with three different x-ray sources. Furthermore, to investigate the dose deposited in a typical small animal XLCT imaging scan, dose estimations from six angular projections by the three different x-ray source energies were performed on a mouse trunk model composed of muscle, spine bone, and a tumor.
Results: With the Sigray source from Sigray Inc, the bone marrow in the mouse leg model was estimated to have a radiation dose of 43 mGy for typical XLCT imaging with six angular projections, 100 micrometer scan step size, and 106 x-ray photons per linear scan. The spine bone, muscle tissues, and tumor structures of the mouse trunk model received a radiation dose of 38.49 mGy, 15.07 mGy, and 16.87 mGy respectively after six angular projections with 100 micrometer scan step size, and 106 x-ray photons per linear scan.
Conclusion: A typical pencil beam based XLCT imaging has an acceptable dose deposited in small animals when six projections of measurements are used.
Not Applicable / None Entered.
Not Applicable / None Entered.