Terahertz (THz) wave, which lies in the frequency gap between infrared and microwave, has an electromagnetic spectrum conventionally defined in the range from 0.1 to 30 THz. [1][2][3] Because its corresponding photon energy has a scale of milli-electron volt (meV) coinciding with the energy scale of many collective excitations in materials, [1] it has a great potential in fundamental scientific research, [4][5][6][7] THz imaging [8,9] and security applications [3] . Driven by these scientific and technological prospects, many efforts have thus been directed towards the development of new THz sources which are powerful,

No abstract

Hand gesture recognition is very significant for human-computer interaction. In this work, we present a novel real-time method for hand gesture recognition. In our framework, the hand region is extracted from the background with the background subtraction method. Then, the palm and fingers are segmented so as to detect and recognize the fingers. Finally, a rule classifier is applied to predict the labels of hand gestures. The experiments on the data set of 1300 images show that our method performs well and is highly efficient. Moreover, our method shows better performance than a state-of-art method on another data set of hand gestures.

Background and Purpose: Stereotactic body radiation therapy delivered using MR-guided radiotherapy (MRgRT) and automatic breathold gating has shown to improve overall survival for locally advanced pancreatic cancer (LAPC) patients. The goal of our study was to evaluate feasibility of treating LAPC patients using abdominal compression (AC) and impact of potential intrafraction motion on planned dose on a 1.5T MR-linac. Methods & Materials: Ten LAPC patients were treated with MRgRT to 50 Gy in 5 fractions with daily online plan adaptation and AC. Three orthogonal plane cine MRI were acquired to assess stability of AC pressure in minimizing tumor motion. Three sets of T2w MR scans, pre-treatment (MRI pre ), verification (MRI ver ) and posttreatment (MRI post ) MRI, were acquired for every fraction. A total of 150 MRIs and doses were evaluated. Impact of intrafraction organ motion was evaluated by propagating pre-treatment plan and structures to MRI ver and MRI post , editing contours and recalculating doses. Gross tumor volume (GTV) coverage and organs-at-risk (OARs) doses were evaluated on MRI ver and MRI post . Results: Median total treatment time was 75.5 (49-132) minutes. Median tumor motion in AC for all fractions was 1.7 (0.7-7), 2.1 (0.6-6.3) and 4.1 (1.4-10.0) mm in anterior-posterior, left-right and superior-inferior direction. Median GTV V50Gy was 78.7%. Median D5cm 3 stomach_duodenum was 24.2 (18.4-29.3) Gy on MRI ver and 24.2 (18.3-30.5) Gy on MRI post . Median D5cm 3 small bowel was 24.3 (18.2-32.8) Gy on MRI ver and 24.4 (16.0-33.6) Gy on MRI post . Conclusion: Dose-volume constraints for OARs were exceeded for some fractions on MRI ver and MRI post . Longer follow up is needed to see the dosimetric impact of intrafraction motion on gastrointestinal toxicity.