Figure 1
From: Imaging of X-Ray-Excited Emissions from Quantum Dots and Biological Tissue in Whole Mouse
Excitation of NIR emission from quantum dots by X-ray excitation. (a) The excitation and imaging system uses a clinical diagnostic X-ray source operating at keV energies, irradiating a sample within a custom-made light-tight housing. NIR emission from QDs in the sample is detected using an off-the-shelf EM-CCD and lens, the latter protruding into the light-tight box through a lead shield either directly (as illustrated) or via a 45° fold mirror to improve the exclusion of scattered X-rays. (b) NIR images of five syringes, arranged side-by-side, containing 0.1 ml aqueous suspensions of, from left to right, 0 (control), 0.005, 0.016, 0.13 and 0.46 mg of CdTe, irradiated by X-rays at (top) 55 kVp and (bottom) 100 kVp. In all cases, the first syringe containing the water control (yellow box) has no visible emission. The 100 kVp image is the average of four 1 second exposures with maximum-pixel rejection (to minimise scattered X-ray contamination; examples of artefacts indicated). (c) Variation of detected NIR emission per cGy dose with CdTe concentration and kVp setting, over rectangular regions of interest (ROIs) for each syringe. The typical uncertainty (1σ) is ± 92 photons per cGy at 70 and 100 kVp, and ± 226 photons per cGy at 55 kVp (where only one frame was recorded – Table 1). A 5% uncertainty in concentration is assumed.
