uch work in the emerging field of biometrics has focused on identification applications. Biometrics offers the means to identify individuals without requiring that they carry ID cards and badges or memorize passwords. A leading concern in the development of such applications, however, is how to avoid rejecting valid users or approving impostors. The iris may provide a solution by offering a much more discriminating biometric than fingerprint or face recognition. We have designed and implemented an iris biometric system that can function as an extremely reliable means for personal electronic identification. Further, our system solves problems associated with public-use devices such as automated teller machines, where habituated use is not the norm. The system also addresses personal-use devices, such as home banking, and other Internet and network applications, such as secure business log-ons.

Real-time motion monitoring of lung tumors with low-field magnetic resonance imaging-guided linear accelerators (MR-Linacs) is currently limited to sagittal 2D cine magnetic resonance imaging (MRI). To provide input data for improved intrafractional and interfractional adaptive radiotherapy, the 4D anatomy has to be inferred from data with lower dimensionality. The purpose of this study was to experimentally validate a previously proposed propagation method that provides continuous time-resolved estimated 4D-MRI based on orthogonal cine MRI for a low-field MR-Linac. Ex vivo porcine lungs were injected with artificial nodules and mounted in a dedicated phantom that allows for the simulation of periodic and reproducible breathing motion. The phantom was scanned with a research version of a commercial 0.35 T MR-Linac. Respiratory-correlated 4D-MRI were reconstructed and served as ground truth images. Series of interleaved orthogonal slices in sagittal and coronal orientation, intersecting the injected targets, were acquired at 7.3 Hz. Estimated 4D-MRI at 3.65 Hz were created in post-processing using the propagation method and compared to the ground truth 4D-MRI. Eight datasets at different breathing frequencies and motion amplitudes were acquired for three porcine lungs. The overall median (95 t h percentile) deviation between ground truth and estimated deformation vector fields was 2.3 mm (5.7 mm), corresponding to 0.7 (1.6) times the in-plane imaging resolution (3.5 × 3.5 mm2). Median (95 t h percentile) estimated nodule position errors were 1.5 mm (3.8 mm) for nodules intersected by orthogonal slices and 2.1 mm (7.1 mm) for nodules located more than 2 cm away from either of the orthogonal slices. The estimation error depended on the breathing phase, the motion amplitude and the location of the estimated position with respect to the orthogonal slices. By using the propagation method, the 4D motion within the porcine lung phantom could be accurately and robustly estimated. The method could provide valuable information for treatment planning, real-time motion monitoring, treatment adaptation, and post-treatment evaluation of MR-guided radiotherapy treatments.

A method for finding closed-form solutions for the normal mode frequencies of systems with circulant (2 pi/n) symmetry was investigated. This method is particularly useful for questions of degeneracy that arise when one considers parallel imaging techniques like SENSE and SMASH in MRI. It is applicable to systems that include birdcage coils as well as planar coils with the appropriate rotational symmetry. A proof is given that complete degeneracy of all normal mode frequencies is impossible when all mutual inductive couplings are included. We tested the method against measurements made on a planar coil array and on an 8-element birdcage coil. The inclusion of the co-rotating end-ring mode changes the fundamental symmetry of the system from circulant to 'bordered circulant.' Closed-form solutions for the normal mode frequencies of a bordered circulant system are also given.

Social anxiety disorder (SAD) is the most common anxiety disorder and has considerable negative impact on social functioning, quality of life, and career progression of those affected. Gelotophobia (the fear of being laughed at) shares many similarities and has therefore been proposed as a subtype of SAD. This hypothesis has, however, never been tested in a clinical sample. Thus, the relationship between gelotophobia, SAD and avoidant personality disorder (APD) was investigated by examining a sample of 133 participants (64 psychiatric patients and 69 healthy controls matched for age and sex) using the Structured Clinical Interview for the Diagnostic and Statistical Manual of Mental Disorders (4th edition) and an established rating instrument for gelotophobia (GELOPH<15>). As expected, gelotophobia scores and the number of gelotophobic individuals were significantly higher among patients with SAD (n = 22) and APD (n = 12) compared to healthy controls and other psychiatric patients. Furthermore, gelotophobia scores were highest in patients suffering from both SAD and APD. In fact, all patients suffering from both disorders were also suffering from gelotophobia. As explained in the discussion, the observed data did not suggest that gelotophobia is a subtype of SAD. The findings rather imply that the fear of being laughed at is a symptom characteristic for both SAD and APD. Based on that, gelotophobia may prove to be a valuable additional diagnostic criterion for SAD and APD and the present results also contribute to the ongoing debate on the relationship between SAD and APD.

To study the dosimetric effect of Qfix kVue Calypso-compatible couch top and rails for spine stereotactic body radiation therapy (SBRT) patients treated with intensity modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT) techniques. Materials/Methods: The computed tomography (CT) dataset for Qfix kVue Calypso-compatible couch top with rails were imported into the treatment planning system (TPS). Ten patients who underwent spine SBRT at our institution were selected for this study. The patients were treated initially on a stereotactic linear accelerator without the couch being part of the dose calculation. Eight patients were treated with static IMRT posterior fields and 2 patients were treated using the VMAT technique. Couch top and rails were added to the structures as support devices and the dose was recalculated for (a) couch top and rails (CR) (b) couch-top and no rails (CNR), then the results were compared the results to no couch-top no-rails (NCNR). Dose covering 100% of the target volume (D100%), dose covering 99% of the target volume (D99%), dose covering 95% of the target volume (D95%), dose covering 90% of the target volume (D90%), volume receiving 100% of the prescription dose (V100%), conformal index (CI), dose gradient index (DGI), and spinal cord threshold and maximum doses were compared to the initial plan with NCNR.