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TU‐H‐CAMPUS‐TeP3‐04: Probing the Dose Enhancement Due to a Clinically‐Relevant Concentration of Gold Nanoparticles and Yb‐169 Gamma Rays Using PRESAGE Dosimeters
Author(s) -
Cho J,
Alqathami M,
Reynoso F,
Cho S
Publication year - 2016
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.4957707
Subject(s) - dosimeter , irradiation , gamma ray , cuvette , dosimetry , materials science , radiochemistry , nanoparticle , absorbed dose , nuclear medicine , nuclear chemistry , analytical chemistry (journal) , chemistry , optics , nanotechnology , physics , nuclear physics , medicine , chromatography
Purpose: To probe physical evidences of the dose enhancement due to a low/clinically‐relevant concentration of gold nanoparticles (GNPs) and Yb‐169 gamma rays using PRESAGE dosimeters. Methods: A PRESAGE cuvette was placed at approximately 2 mm above the plane containing three novel Yb‐169 brachytherapy seeds (3.2, 3.2, and 5.3 mCi each). Two types of PRESAGE dosimeters were used – plain PRESAGEs (controls) and PRESAGEs loaded with 0.02 wt. % of GNPs (GNP‐PRESAGEs). Each PRESAGE dosimeter was irradiated with different time durations (0 to 24 hours) to deliver 0, 4, 8, 16 and 24 Gy of dose. For a reference/comparison, both types of PRESAGEs were also irradiated using 250 kVp x‐rays with/without Er‐filter to deliver 0, 3, 10, and 30 Gy of dose. Er‐filter was used to emulate Yb‐169 spectrum using 250 kVp x‐rays. The absorption spectra of PRESAGEs were measured using a UV spectrophotometer and used to determine the corresponding optical densities (ODs). Results: GNP‐PRESAGEs exposed to Yb‐169 sources showed ∼65% increase in ODs compared with controls. When exposed to Er‐filtered and unfiltered 250 kVp x‐rays, they produced smaller increases in ODs, ∼41% and ∼37%, respectively. There was a linear relationship between ODs and delivered doses with a goodness‐of‐fit (R2) greater than 0.99. Conclusion: A notable increase in the ODs (∼65%) was observed for GNP‐PRESAGEs irradiated by Yb‐169 gamma rays. Considering the observed OD increases, it was highly likely that Yb‐169 gamma rays were more effective than both Er‐filtered and unfiltered 250 kVp x‐rays, in terms of producing the dose enhancement. Due to several unknown factors (e.g., possible difference in the dose response of GNP‐PRESAGEs vs. PRESAGEs), however, a further investigations is necessary to establish the feasibility of quantifying the exact amount of macroscopic or microscopic/local GNP‐mediated dose enhancement using PRESAGE or similar volumetric dosimeters. Supported by DOD/PCRP grant W81XWH‐12‐1‐0198 This investigation was supported by DOD/PCRP grant W81XWH‐12‐1‐0198.