Program Information
Using Radiotherapy Biomaterials to Brand and Track Deadly Cancer Cells
Y Altundal1*, E Sajo1 , W Ngwa1,2 (1) Univ Massachusetts Lowell, Lowell, MA, (2) Brigham and Women's Hospital, Dana Farber Cancer Institute, Harvard Medical, Boston, MA
Presentations
SU-D-210-4 (Sunday, July 12, 2015) 2:05 PM - 3:00 PM Room: 210
Purpose: Metastasis accounts for over 90% of all cancer associated suffering and death and arguably presents the most formidable challenges in cancer management. The detection of metastatic or rare circulating tumor cells (CTCs) in blood or lymph nodes remains a formidable technological challenge. In this study, we investigated the time needed to label each cancer cell in-situ (right at the source tumor) with sufficient number of GNPs that will allow enhanced non-invasive detection via photoacoustic imaging in the lymph nodes. Such in-situ labeling can be achieved via sustained release of the GNPs from Radiotherapy (RT) biomaterials (e.g. fiducials, spacers) coated/loaded with the GNP.
Methods: The minimum concentration (1000 GNPs/cell for 50nm GNPs) to detect GNPs with photoacoustic imaging method was experimentally measured by Mallidi et al. and fixed at the tumor sub-volume periphery. In this work, the GNPs were assumed to diffuse from a point source, placed in the middle of a 2-3cm tumor, with an initial concentration of 7-30 mg/g. The time required to label the cells with GNPs was calculated by solving the three dimensional diffusion-reaction equation analytically. The diffusion coefficient of 10nm GNPs was experimentally determined previously. Stokes-Einstein equation was used to calculate the diffusion coefficients for other sizes (2-50nm) of GNPs. The cellular uptake rate constants for several sizes of GNPs were experimentally measured by Jin et al.
Results: The time required to label the cells was found 0.635-15.91 days for 2-50nm GNPs with an initial concentration of 7 mg/g GNPs in a 2 cm tumor; 1.379-34.633 days for 2-50nm GNPs with an initial concentration of 30 mg/g GNPs in a 3cm tumor.
Conclusion: Our results highlight new potential for labeling CTCs with GNPs released from smart RT biomaterials (i.e. fiducials or spacers loaded with the GNP) towards enhanced non-invasive imaging/detection via photoacoustic imaging.
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