PURPOSE Biological soft tissues encountered in clinical and preclinical imaging mainly consists of atoms of light elements with low atomic numbers and their elemental composition is nearly uniform with little density variation. Hence, x-ray attenuation contrast is relatively poor and cannot achieve satisfactory sensitivity and specificity. In contrast, x-ray phase-contrast provides a new mechan...

This paper describes a statistical image reconstruction method for x-ray CT that is based on a physical model that accounts for the polyenergetic x-ray source spectrum and the measurement nonlinearities caused by energy-dependent attenuation. Unlike our earlier work, the proposed algorithm does not require pre-segmentation of the object into the various tissue classes (e.g., bone and soft tissu...

Recent studies of Quasi-Stellar Objects (QSOs) with ROSAT suggest the existence of a significant population of Soft X-ray Weak QSOs (SXW QSOs) where the soft X-ray flux is ∼ 10–30 times smaller than in typical QSOs. Why are these QSOs soft X-ray weak, and what is their relationship to Broad Absorption Line QSOs (BAL QSOs) and X-ray warm absorber QSOs? As a first step in a systematic study of th...

Electrophotography is a very useful tool for x-ray diagnosis of the soft tissue and the bone due to the edge effect having wide latitude and high contrast. However, in usual electroradiography, larger exposure doses are necessary compared to silver haloid method owing to the low sensitivtity to x-rays. Very sensitive electroradiography is developed as K.I.P. method, using special photoconductiv...

Seeding soft-X-ray plasma amplifiers with high harmonics has been demonstrated to generate high-brightness soft-X-ray laser pulses with full spatial and temporal coherence1–3. The interaction between the injected coherent field and the swept-gain medium has been modelled4,5. However, no experiment has been conducted to probe the gain dynamics when perturbed by a strong external seed field. Here...

The digit ratio (2D:4D) is sexually dimorphic and has been considered an indicator of prenatal sex hormone exposure. Previous studies have shown that males tend to have lower 2D to 4D ratio than females, and this sexual dimorphism has been reported across different ethnic groups and different countries. However, digit ratio data are missing from the Han ethnicity in China. Furthermore, most of ...

Neurofibroma is a tumor composed of a complex proliferation of neuromesenchymal tissue (Schwann cells, perineural cells, fibroblast, and mast cells). We report a 45-year-old female who had a slow growing, large, soft, pedunculated mass on her left lateral neck. A skin biopsy confirmed the diagnosis of neurofibroma.