Browsing by Author "Huang, Chih-Chia"

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Automated Segmentation of Dental Calculus in Optical Coherence Tomography Images
(2018-01-01)
Lee, Chia-Yen
;
Chuang, Ching-Cheng
;
Chen, Guan-Jie
;
Huang, Chih-Chia
;
Lee, Shyh-Yuan
The presence of dental calculus is highly correlated with the formation and advancement of periodontal disease. The occurrence and relapse of periodontal disease can be prevented only if dental calculus is completely removed. In this study, optical coherence tomography (OCT) is used to obtain two-dimensional cross-sectional images of tooth samples, in conjunction with a segmentation technique that enables automatic identification of dental calculus. We propose the vertical intensity transform function to correct the nonuniform instrument signal intensity caused by OCT. Afterwards, the detection ranges are defined by K-means or the Markov random field (MRF), and the candidate range is selected on the basis of mathematical morphology (MM). Finally, the features (thickness gradient, texture, and tooth surface slope) are quantified, and dental calculus is recognized and segmented. In the preliminary result, the sensitivity is 87.5%. The mean distance between the boundaries generated by the proposed algorithm and the corresponding manually delineated boundaries is 2.52 +/- 3.54 pixels. Our proposed algorithm assists physicians to determine dental calculus more easily. Doctors no longer need to rely solely on their experiences to recognize dental calculus, but can refer to specific data to assist in diagnosis.
New insight on optical and magnetic Fe3O4 nanoclusters promising for near infrared theranostic applications
(2015-01-01)
Huang, Chih-Chia
;
Chang, Po-Yang
;
Liu, Chien-Liang
;
Xu, Jia-Pu
;
Wu, Shu-Pao
Extensive efforts have been devoted to the development of a new biophotonic system using near infrared (NIR) nano-agents for non-invasive cancer diagnosis and therapy. Here, we developed a simple synthesis reaction of ligands, hydrazine, and iron(II) chloride to fabricate Fe3O4 cluster-structured nanoparticles (CNPs) with interesting NIR photonics and high magnetization (M-s: 98.3 emu g(-1) and proton relaxivity r(2): 234.6 mM(-1) s(-1)). These Fe3O4 CNPs exhibited optical absorption and reflection over all wavelengths, showing a U-shape absorption band with a low absorbance at a range of 750-950 nm and a progressive evolution in the second near infrared region. Strengthening of the scattering effect by incubating Fe3O4 CNPs with HeLa cells was observed when optical contrast enhancement was performed in an optical coherence tomography (OCT) microscope system with a laser light source at 860 nm. Using a 1064 nm laser at a low power density (380 mW cm(-2)) to excite the Fe3O4 CNPs (375 ppm([Fe])) led to a rise in the water temperature from 25 degrees C to 58 degrees C within 10 min. Finally, we present the first example of magneto-motive OCT cellular imaging combined with enhanced photothermal therapy using Fe3O4 CNPs and applying a magnetic field, which is promising for preclinical and clinical trials in the future.