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[Abstract]

PURPOSE: In radiotherapy, metallic implants often detach from their deposited sites and migrate to other locations. This undesirable migration could cause inadequate dose coverage for permanent brachytherapy and difficulties in image-guided radiation delivery for patients. To prevent migration of implanted seeds, the authors propose a potential strategy to use a biocompatible and tissue-adhesive material called polydopamine.

METHODS: In this study, nonradioactive dummy seeds that have the same geometry and composition as commercial I-125 seeds were coated in polydopamine. Using scanning electron microscopy and x-ray photoelectron spectroscopy, the surface of the polydopamine-coated and noncoated seeds was characterized. The detachment stress between the two types of seeds and the tissue was measured. The efficacy of polydopamine-coated seed was investigated through in vitro migration tests by tracing the seed location after tissue implantation and shaking for given times. The cytotoxicity of the polydopamine coating was also evaluated.

RESULTS: The results of the coating characterization have shown that polydopamine was successfully coated on the surface of the seeds. In the adhesion test, the polydopamine-coated seeds had 2.1-fold greater detachment stress than noncoated seeds. From the in vitro test, it was determined that the polydopamine-coated seed migrated shorter distances than the noncoated seed. This difference was increased with a greater length of time after implantation.

CONCLUSIONS: The authors suggest that polydopamine coating is an effective technique to prevent migration of implanted seeds, especially for permanent prostate brachytherapy.

[Author information]

Lee H1, Lee WS2, Park JI1, Son KJ3, Park M2, Bang YB4, Choy YB5, Ye SJ6.

1 Program in Biomedical Radiation Sciences, Department of Transdisciplinary Studies, Graduate School of Convergence Science and Technology, Seoul National University, Seoul 151-742, Korea.

2 Interdisciplinary Program in Bioengineering, Seoul National University College of Engineering, Seoul 151-742, Korea.

3 Hanaro Applications Research, Korea Atomic Energy Research Institute, Daejeon 305-353, Korea.

4 Advanced Institutes of Convergence Technology, Seoul National University, Suwon 443-270, Korea.

5 Interdisciplinary Program in Bioengineering, Seoul National University College of Engineering, Seoul 110-744, Korea; Department of Biomedical Engineering, Seoul National University College of Medicine, Seoul 110-744, Korea; and Institute of Medical and Biological Engineering, Medical Research Center, Seoul National University, Seoul 110-744, Korea.

6 Program in Biomedical Radiation Sciences, Department of Transdisciplinary Studies, Graduate School of Convergence Science and Technology, Seoul National University, Seoul 151-742, Korea; Advanced Institutes of Convergence Technology, Seoul National University, Suwon 443-270, Korea; and Department of Radiation Oncology, Seoul National University Hospital, Seoul 110-744, Korea.