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Title: SU-F-T-10: Validation of ELP Dosimetry Using PRESAGE Dosimeter: Feasibility Test and Practical Considerations

Abstract

Purpose: To validate the use of a PRESAGE dosimeter as a method to quantitatively measure dose distributions of injectable brachytherapy based on elastin-like polypeptide (ELP) nanoparticles. PRESAGE is a solid, transparent polyurethane-based dosimeter whose dose is proportional to a change in optical density, making it useful for visualizing the dose from a radionuclide-tagged-ELP injection. Methods: A PRESAGE dosimeter was designed to simulate an ELP injection. To calibrate, cuvette samples from the batch of PRESAGE were exposed to varying levels of radiation from 0–35.9Gy applied via a linear accelerator, then placed into a spectrophotometer to obtain the optical density change as a function of dose. A pre-optical-CT scan was acquired of the phantom to obtain a baseline tomographic optical density. A 1cc saline solution of I-125 tagged-ELP with and activity concentration of 1mCi/cc was injected into the phantom and left for five days. After five days, the ELP was removed and the cavity cleaned of all remaining radioactive material. Post tomographic optical images were acquired to obtain a differential optical density dataset. Results: Initial results after the 5-day exposure revealed an opaque white film that resembled the volume of the ELP solution injected into the phantom. We think this is possiblymore » due to the saline solution diffusing into the PRESAGE and causing a change in the index of refraction at this shallow depth. Therefore, initially the optical scanner yielded inconclusive results. After several more days, the saline seemed to have evaporated out of the injection site and the ELP dose distribution was visible via color change in the dosimeter. Conclusion: We have created the first experimental design to measure the dose distribution of I-125-tagged-ELP. The PRESAGE formulation proves to be a feasible option for such measurements. Future experimental measurements need to be obtained to further characterize ELP dosimetry.« less

Authors:
; ; ;  [1]; ;  [2]; ;  [1];  [3]
  1. Duke University Medical Physics Program, Durham, NC (United States)
  2. Duke University Department of Biomedical Engineering, Durham, NC (United States)
  3. (United States)
Publication Date:
OSTI Identifier:
22642260
Resource Type:
Journal Article
Resource Relation:
Journal Name: Medical Physics; Journal Volume: 43; Journal Issue: 6; Other Information: (c) 2016 American Association of Physicists in Medicine; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
61 RADIATION PROTECTION AND DOSIMETRY; 60 APPLIED LIFE SCIENCES; BRACHYTHERAPY; COMPUTERIZED TOMOGRAPHY; DATASETS; DOSEMETERS; DOSIMETRY; INJECTION; IODINE 125; LINEAR ACCELERATORS; OPACITY; PHANTOMS; POLYPEPTIDES; POLYURETHANES; RADIATION DOSE DISTRIBUTIONS; RADIATION DOSES; REFRACTIVE INDEX; VALIDATION

Citation Formats

Lambson, K, Lafata, K, Miles, D, Yoon, S, Schaal, J, Liu, W, Oldham, M, Cai, J, and Duke University Medical Center, Radiation Oncology, Durham, NC. SU-F-T-10: Validation of ELP Dosimetry Using PRESAGE Dosimeter: Feasibility Test and Practical Considerations. United States: N. p., 2016. Web. doi:10.1118/1.4956144.
Lambson, K, Lafata, K, Miles, D, Yoon, S, Schaal, J, Liu, W, Oldham, M, Cai, J, & Duke University Medical Center, Radiation Oncology, Durham, NC. SU-F-T-10: Validation of ELP Dosimetry Using PRESAGE Dosimeter: Feasibility Test and Practical Considerations. United States. doi:10.1118/1.4956144.
Lambson, K, Lafata, K, Miles, D, Yoon, S, Schaal, J, Liu, W, Oldham, M, Cai, J, and Duke University Medical Center, Radiation Oncology, Durham, NC. Wed . "SU-F-T-10: Validation of ELP Dosimetry Using PRESAGE Dosimeter: Feasibility Test and Practical Considerations". United States. doi:10.1118/1.4956144.
@article{osti_22642260,
title = {SU-F-T-10: Validation of ELP Dosimetry Using PRESAGE Dosimeter: Feasibility Test and Practical Considerations},
author = {Lambson, K and Lafata, K and Miles, D and Yoon, S and Schaal, J and Liu, W and Oldham, M and Cai, J and Duke University Medical Center, Radiation Oncology, Durham, NC},
abstractNote = {Purpose: To validate the use of a PRESAGE dosimeter as a method to quantitatively measure dose distributions of injectable brachytherapy based on elastin-like polypeptide (ELP) nanoparticles. PRESAGE is a solid, transparent polyurethane-based dosimeter whose dose is proportional to a change in optical density, making it useful for visualizing the dose from a radionuclide-tagged-ELP injection. Methods: A PRESAGE dosimeter was designed to simulate an ELP injection. To calibrate, cuvette samples from the batch of PRESAGE were exposed to varying levels of radiation from 0–35.9Gy applied via a linear accelerator, then placed into a spectrophotometer to obtain the optical density change as a function of dose. A pre-optical-CT scan was acquired of the phantom to obtain a baseline tomographic optical density. A 1cc saline solution of I-125 tagged-ELP with and activity concentration of 1mCi/cc was injected into the phantom and left for five days. After five days, the ELP was removed and the cavity cleaned of all remaining radioactive material. Post tomographic optical images were acquired to obtain a differential optical density dataset. Results: Initial results after the 5-day exposure revealed an opaque white film that resembled the volume of the ELP solution injected into the phantom. We think this is possibly due to the saline solution diffusing into the PRESAGE and causing a change in the index of refraction at this shallow depth. Therefore, initially the optical scanner yielded inconclusive results. After several more days, the saline seemed to have evaporated out of the injection site and the ELP dose distribution was visible via color change in the dosimeter. Conclusion: We have created the first experimental design to measure the dose distribution of I-125-tagged-ELP. The PRESAGE formulation proves to be a feasible option for such measurements. Future experimental measurements need to be obtained to further characterize ELP dosimetry.},
doi = {10.1118/1.4956144},
journal = {Medical Physics},
number = 6,
volume = 43,
place = {United States},
year = {Wed Jun 15 00:00:00 EDT 2016},
month = {Wed Jun 15 00:00:00 EDT 2016}
}