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Title: Preclinical investigation for developing injectable fiducial markers using a mixture of BaSO{sub 4} and biodegradable polymer for proton therapy

Abstract

Purpose: The aim of this study is to investigate the use of mixture of BaSO{sub 4} and biodegradable polymer as an injectable nonmetallic fiducial marker to reduce artifacts in x-ray images, decrease the absorbed dose distortion in proton therapy, and replace permanent metal markers. Methods: Two samples were made with 90 wt. % polymer phosphate buffer saline (PBS) and 10 wt. % BaSO{sub 4} (B1) or 20 wt. % BaSO{sub 4} (B2). Two animal models (mice and rats) were used. To test the injectability and in vivo gelation, a volume of 200 μl at a pH 5.8 were injected into the Sprague-Dawley rats. After sacrificing the rats over time, the authors checked the gel morphology. Detectability of the markers in the x-ray images was tested for two sizes (diameters of 1 and 2 mm) for B1 and B2. Four samples were injected into BALB/C mice. The polymer mixed with BaSO{sub 4} transform from SOL at 20 °C with a pH of 6.0 to GEL in the living body at 37 °C with a pH of 7.4, so the size of the fiducial marker could be controlled by adjusting the injected volume. The detectability of the BaSO{sub 4} marker was measured in x-raymore » images of cone beam CT (CBCT), on-board imager [anterior–posterior (AP), lateral], and fluoroscopy (AP, lateral) using a Novalis-TX (Varian Medical Systems, Palo Alto, CA) repeatedly over 4 months. The volume, HU, and artifacts for the markers were measured in the CBCT images. Artifacts were compared to those of gold marker by analyzing the HU distribution. The dose distortion in proton therapy was computed by using a Monte Carlo (MC) code. A cylindrical shaped marker (diameter: 1 or 2 mm, length: 3 mm) made of gold, stainless-steel [304], titanium, and 20 wt. % BaSO{sub 4} was positioned at the center of the spread-out Bragg peak (SOBP) in parallel or perpendicular to the beam entrance. The dose distortion was measured on the depth dose profile across the markers. Results: Transformation to GEL and the biodegradation were verified. All BaSO{sub 4} markers could be detected in the CBCT. In the OBI and fluoroscopy images, all markers visible in the AP, but only B2(2 mm) could be identified in the lateral images. Changes of BaSO{sub 4} position were not detected in vivo (mice). The volume of the markers decreased by up to 65% and the HU increased by 22%, on average. The mean HU values around the B1, B2, and gold markers were 121.30 [standard deviation (SD): 54.86], 126.31 (SD: 62.13), and 1070.7 (SD: 235.16), respectively. The MC-simulated dose distortion for the BaSO{sub 4} markers was less than that of the commercially used markers. The dose reduction due to the gold marker was largest (15.05%) followed by stainless steel (7.92%) and titanium (6.92%). Dose reduction by B2 (2 mm) was 4.75% and 0.53% in parallel and perpendicular orientations, respectively. Conclusions: BaSO{sub 4} mixed with PBS is a good contrast agent in biodegradable polymer marker because of minimal artifacts in x-ray images and minimal dose reduction in proton therapy. The flexibility of the size is considered to be an advantage of this material over solid type fiducials.« less

Authors:
 [1]; ;  [2]; ; ; ; ; ; ;  [3];  [4]; ;  [5]
  1. Department of Health Sciences and Technology, Samsung Advanced Institute for Health Sciences and Technology, Sungkyunkwan University, Seoul 135-710 (Korea, Republic of)
  2. Sungkyunkwan University School of Chemical Engineering, Suwon 440-746 (Korea, Republic of)
  3. Department of Radiation Oncology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 135-710 (Korea, Republic of)
  4. Department of Radiation Oncology, Case Medical Center, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106 (United States)
  5. Department of Radiation Oncology, Samsung Medical Center, Seoul 135-710 (Korea, Republic of)
Publication Date:
OSTI Identifier:
22413567
Resource Type:
Journal Article
Journal Name:
Medical Physics
Additional Journal Information:
Journal Volume: 42; Journal Issue: 5; Other Information: (c) 2015 American Association of Physicists in Medicine; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0094-2405
Country of Publication:
United States
Language:
English
Subject:
63 RADIATION, THERMAL, AND OTHER ENVIRONMENTAL POLLUTANT EFFECTS ON LIVING ORGANISMS AND BIOLOGICAL MATERIALS; 60 APPLIED LIFE SCIENCES; ABSORBED RADIATION DOSES; BARIUM SULFATES; BRAGG CURVE; CONTRAST MEDIA; DEPTH DOSE DISTRIBUTIONS; FIDUCIAL MARKERS; GOLD; MICE; PROTON BEAMS; RADIOTHERAPY; RATS; STAINLESS STEEL-304; TITANIUM; X RADIATION

Citation Formats

Ahn, Sang Hee, Gil, Moon Soo, Lee, Doo Sung, Han, Youngyih, E-mail: youngyih@skku.edu, E-mail: Hee.ro.Park@samsung.com, Park, Hee Chul, E-mail: youngyih@skku.edu, E-mail: Hee.ro.Park@samsung.com, Yu, Jeong Il, Noh, Jae Myoung, Cho, Jun Sang, Ahn, Sung Hwan, Choi, Doo Ho, Sohn, Jason W., Kim, Hye Yeong, and Shin, Eun Hyuk. Preclinical investigation for developing injectable fiducial markers using a mixture of BaSO{sub 4} and biodegradable polymer for proton therapy. United States: N. p., 2015. Web. doi:10.1118/1.4916663.
Ahn, Sang Hee, Gil, Moon Soo, Lee, Doo Sung, Han, Youngyih, E-mail: youngyih@skku.edu, E-mail: Hee.ro.Park@samsung.com, Park, Hee Chul, E-mail: youngyih@skku.edu, E-mail: Hee.ro.Park@samsung.com, Yu, Jeong Il, Noh, Jae Myoung, Cho, Jun Sang, Ahn, Sung Hwan, Choi, Doo Ho, Sohn, Jason W., Kim, Hye Yeong, & Shin, Eun Hyuk. Preclinical investigation for developing injectable fiducial markers using a mixture of BaSO{sub 4} and biodegradable polymer for proton therapy. United States. doi:10.1118/1.4916663.
Ahn, Sang Hee, Gil, Moon Soo, Lee, Doo Sung, Han, Youngyih, E-mail: youngyih@skku.edu, E-mail: Hee.ro.Park@samsung.com, Park, Hee Chul, E-mail: youngyih@skku.edu, E-mail: Hee.ro.Park@samsung.com, Yu, Jeong Il, Noh, Jae Myoung, Cho, Jun Sang, Ahn, Sung Hwan, Choi, Doo Ho, Sohn, Jason W., Kim, Hye Yeong, and Shin, Eun Hyuk. Fri . "Preclinical investigation for developing injectable fiducial markers using a mixture of BaSO{sub 4} and biodegradable polymer for proton therapy". United States. doi:10.1118/1.4916663.
@article{osti_22413567,
title = {Preclinical investigation for developing injectable fiducial markers using a mixture of BaSO{sub 4} and biodegradable polymer for proton therapy},
author = {Ahn, Sang Hee and Gil, Moon Soo and Lee, Doo Sung and Han, Youngyih, E-mail: youngyih@skku.edu, E-mail: Hee.ro.Park@samsung.com and Park, Hee Chul, E-mail: youngyih@skku.edu, E-mail: Hee.ro.Park@samsung.com and Yu, Jeong Il and Noh, Jae Myoung and Cho, Jun Sang and Ahn, Sung Hwan and Choi, Doo Ho and Sohn, Jason W. and Kim, Hye Yeong and Shin, Eun Hyuk},
abstractNote = {Purpose: The aim of this study is to investigate the use of mixture of BaSO{sub 4} and biodegradable polymer as an injectable nonmetallic fiducial marker to reduce artifacts in x-ray images, decrease the absorbed dose distortion in proton therapy, and replace permanent metal markers. Methods: Two samples were made with 90 wt. % polymer phosphate buffer saline (PBS) and 10 wt. % BaSO{sub 4} (B1) or 20 wt. % BaSO{sub 4} (B2). Two animal models (mice and rats) were used. To test the injectability and in vivo gelation, a volume of 200 μl at a pH 5.8 were injected into the Sprague-Dawley rats. After sacrificing the rats over time, the authors checked the gel morphology. Detectability of the markers in the x-ray images was tested for two sizes (diameters of 1 and 2 mm) for B1 and B2. Four samples were injected into BALB/C mice. The polymer mixed with BaSO{sub 4} transform from SOL at 20 °C with a pH of 6.0 to GEL in the living body at 37 °C with a pH of 7.4, so the size of the fiducial marker could be controlled by adjusting the injected volume. The detectability of the BaSO{sub 4} marker was measured in x-ray images of cone beam CT (CBCT), on-board imager [anterior–posterior (AP), lateral], and fluoroscopy (AP, lateral) using a Novalis-TX (Varian Medical Systems, Palo Alto, CA) repeatedly over 4 months. The volume, HU, and artifacts for the markers were measured in the CBCT images. Artifacts were compared to those of gold marker by analyzing the HU distribution. The dose distortion in proton therapy was computed by using a Monte Carlo (MC) code. A cylindrical shaped marker (diameter: 1 or 2 mm, length: 3 mm) made of gold, stainless-steel [304], titanium, and 20 wt. % BaSO{sub 4} was positioned at the center of the spread-out Bragg peak (SOBP) in parallel or perpendicular to the beam entrance. The dose distortion was measured on the depth dose profile across the markers. Results: Transformation to GEL and the biodegradation were verified. All BaSO{sub 4} markers could be detected in the CBCT. In the OBI and fluoroscopy images, all markers visible in the AP, but only B2(2 mm) could be identified in the lateral images. Changes of BaSO{sub 4} position were not detected in vivo (mice). The volume of the markers decreased by up to 65% and the HU increased by 22%, on average. The mean HU values around the B1, B2, and gold markers were 121.30 [standard deviation (SD): 54.86], 126.31 (SD: 62.13), and 1070.7 (SD: 235.16), respectively. The MC-simulated dose distortion for the BaSO{sub 4} markers was less than that of the commercially used markers. The dose reduction due to the gold marker was largest (15.05%) followed by stainless steel (7.92%) and titanium (6.92%). Dose reduction by B2 (2 mm) was 4.75% and 0.53% in parallel and perpendicular orientations, respectively. Conclusions: BaSO{sub 4} mixed with PBS is a good contrast agent in biodegradable polymer marker because of minimal artifacts in x-ray images and minimal dose reduction in proton therapy. The flexibility of the size is considered to be an advantage of this material over solid type fiducials.},
doi = {10.1118/1.4916663},
journal = {Medical Physics},
issn = {0094-2405},
number = 5,
volume = 42,
place = {United States},
year = {2015},
month = {5}
}