No abstract

Dual energy chest digital tomosynthesis (CDT) is a recently developed medical technique that takes advantage of both tomosynthesis and dual energy X-ray images. However, quantum noise, which occurs in dual energy X-ray images, strongly interferes with diagnosis in various clinical situations. Therefore, noise reduction is necessary in dual energy CDT. In this study, noise-compensating algorithms, including a simple smoothing of high-energy images (SSH) and anti-correlated noise reduction (ACNR), were evaluated in a CDT system. We used a newly developed prototype CDT system and anthropomorphic chest phantom for experimental studies. The resulting images demonstrated that dual energy CDT can selectively image anatomical structures, such as bone and soft tissue. Among the resulting images, those acquired with ACNR showed the best image quality. Both coefficient of variation and contrast to noise ratio (CNR) were the highest in ACNR among the three different dual energy techniques, and the CNR of bone was significantly improved compared to the reconstructed images acquired at a single energy. This study demonstrated the clinical value of dual energy CDT and quantitatively showed that ACNR is the most suitable among the three developed dual energy techniques, including standard log subtraction, SSH, and ACNR.

In this paper, we propose the design of a wafer-based micro objective lens with numerical aperture (NA) 0.85 using a 405 nm blue-violet laser. The total length of the lens is 1.36 mm. The micro objective lens consists of three layers that are a hologram optical element for reducing the aberration and two grinded and polished ball for making optical power to achieve NA 0.85. The lens could be applied to an integrated optical pickup module. The approximate size of the optical pickup module is 3 mm[W] · 3 mm[D] · 3 mm [H] including the wafer-based objective lens, which is suitable for realizing a small sized optical drive based on Blu-ray Disc. The wafer-based design could offer precise alignment, easy handling and high mass productivity with micro electro mechanical system technology.