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. Author manuscript; available in PMC: 2013 Dec 7.
Published in final edited form as: Phys Med Biol. 2012 Nov 8;57(23):N457–N467. doi: 10.1088/0031-9155/57/23/N457

Figure 6.

Figure 6

Results from measurements of gold fluorescence signal and dose with varying thickness of tin filters. During these measurements, x-ray power setting was kept constant at 105 kVp and 400 µA. Measurements were taken under the same geometry as that resulted in Fig. 2(b). Experimental errors were smaller than the size of symbols. As the thickness of the tin filter increases from 0.9 mm to 3.6 mm, the ratio of gold fluorescence signal (for GNP concentration at 2 wt. %) to delivered dose increases exponentially. However, the scan time to produce the same magnitude of gold fluorescence signal (for GNP concentration at 2 wt. %) also increases with tin filter thickness, at a much higher rate, under the current x-ray tube power setting. Thus, it is imperative to use a higher power x-ray tube in order to fully take advantage of an increased fluorescence signal-to-dose ratio from the use of thicker filters.