The rhythm of chemotherapy and the felt experience of time: a front-loaded phenomenological retrospective cohort study.

It is well-known that chemotherapy brings about various adverse physical effects such as fatigue, nausea, or vomiting, and that it lowers mental well-being. It is less known that it desynchronizes patients with social environment. This study explores the temporal aspects and challenges of chemotherapy. Three groups equal in size and distinguished according to weekly, biweekly, and triweekly treatment schemes, each independently representative in terms of sex and age of the cancer population (total N = 440) were compared. The study found that chemotherapy sessions, regardless of their frequency, patients' age, and the overall length of treatment, have a very large effect on changing the felt pace of time from flying to dragging (Cohen's d = 1.6655). Most patients pay more attention to the passing of time than before treatment (59.3%), which has to do with the disease (77.4%). They also experience the loss of control over time, which they subsequently attempt to regain. The patients' actual activities before and after chemotherapy, however, are mostly the same. All these aspects create a unique 'chemo-rhythm', in which the significance of the type of cancer and demographic variables is negligible, and the mere rhythmic nature of treatment plays a central role. In conclusion, patients find the 'chemo-rhythm' stressful, unpleasant and difficult to control. It is vital to prepare them for it and help to reduce its adverse effects.

Projection extrapolation routine for tight-frame limited-angle optical diffraction tomography.

We propose a data-replenishment-type expansion of the modified Gerchberg-Papoulis (GP) algorithm for limited-angle optical diffraction tomography (LAODT), which prevents artifact buildup in the GP reconstructions of confined bulk objects tightly fitting the active field of view (FoV) of the LAODT microscope. Objects crossing the FoV borders are not considered. The method relies on a Fourier-based forward projector complementary to the GP solver with no additional constraints. Fourier space regridding errors are minimized by means of one-dimensional oversampling in the axial direction, which is demonstrated to be more efficient than standard projection padding. Verification of both synthetic and experimental sinograms confirms the ability of the procedure to deduce missing projection parts necessary for the correct reconstruction.

Color Fourier orthoscopic holography with laser capture and an LED display.

We present an end-to-end full color Fourier holographic imaging approach, which involves standard holographic recording with three wavelengths and an improved LED-driven display. It provides almost undistorted orthoscopic reconstruction of large objects in full color, which can be viewed with a naked eye. High quality reconstruction is preserved across large object depths, measured in meters, as shown theoretically and experimentally. Our imaging approach is based on capture, processing and display of the object wave fields without spherical phase factors. This efficient convention combined with a novel numerical propagator for confocal fields enables complete axial decoupling of both ends of the imaging chain, and consequently, free manipulation of axial position as well as size of the image without visible deformations and with minimal computation effort.

Digital hologram transformations for RGB color holographic display with independent image magnification and translation in 3D.

A new framework for in-plane transformations of digital holograms (DHs) is proposed, which provides improved control over basic geometrical features of holographic images reconstructed optically in full color. The method is based on a Fourier hologram equivalent of the adaptive affine transformation technique [Opt. Express18, 8806 (2010)OPEXFF1094-408710.1364/OE.18.008806]. The solution includes four elementary geometrical transformations that can be performed independently on a full-color 3D image reconstructed from an RGB hologram: (i) transverse magnification; (ii) axial translation with minimized distortion; (iii) transverse translation; and (iv) viewing angle rotation. The independent character of transformations (i) and (ii) constitutes the main result of the work and plays a double role: (1) it simplifies synchronization of color components of the RGB image in the presence of mismatch between capture and display parameters; (2) provides improved control over position and size of the projected image, particularly the axial position, which opens new possibilities for efficient animation of holographic content. The approximate character of the operations (i) and (ii) is examined both analytically and experimentally using an RGB circular holographic display system. Additionally, a complex animation built from a single wide-aperture RGB Fourier hologram is presented to demonstrate full capabilities of the developed toolset.

Generalized total variation iterative constraint strategy in limited angle optical diffraction tomography.

Due to incompleteness of input data inherent to Limited Angle Tomography (LAT), specific additional constraints are usually employed to suppress image artifacts. In this work we demonstrate a new two-stage regularization strategy, named Generalized Total Variation Iterative Constraint (GTVIC), dedicated to semi-piecewise-constant objects. It has been successfully applied as a supplementary module for two different reconstruction algorithms: an X-ray type solver and a diffraction-wise solver. Numerical tests performed on a detailed phantom of a biological cell under conical illumination pattern show significant reduction of axial blurring in the reconstructed refractive index distribution after GTVIC is added. Analogous results were obtained with experimental data.

Approach for fast numerical propagation of uniformly polarized random electromagnetic fields in dispersive linearly birefringent systems.

An efficient simulation technique is proposed for computing propagation of uniformly polarized statistically stationary fields in linear nonimage-forming systems that includes dispersion of linear birefringence to all orders. The method is based on the discrete-time Fourier transformation of modified frequency profiles of the spectral Stokes parameters. It works under the condition that all (linearly) birefringent sections present in the system are described by the same phase birefringence dispersion curve, being a monotonic function of the optical frequency within the bandwidth of the light. We demonstrate the technique as a supplement for the Mueller-Stokes matrix formalism extended to any uniformly polarized polychromatic illumination. Accuracy of its numerical implementation has been verified by using parameters of a Lyot depolarizer made of a highly birefringent and dispersive monomode photonic crystal fiber.

Lyot depolarizer in terms of the theory of coherence--description for light of any spectrum.

A coherence-based description of the Lyot depolarizer illuminated by polychromatic light of any spectral density distribution is proposed as a generalization of the formulas provided for symmetrical spectra by Burns [J. Lightwave Technol. 1, 475 (1983)] and Mochizuki [Appl. Opt. 23, 3284 (1984)]. The structure of the derived expressions is explained in physical terms, and a numerical comparison with the previous solutions is performed. The results of the numerical analysis show that the proposed description, when applied to any configuration of a two-segment anisotropic depolarizer, is fully equivalent with the Mueller-Stokes calculus for broadband light. Following this consistency, the range of accuracy of the formula by Mochizuki has been verified.

Use of the Resection Map system as guidance during hepatectomy.

BACKGROUND: The objective of this work is to evaluate a new concept of intraoperative three-dimensional (3D) visualization system to support hepatectomy. The Resection Map aims to provide accurate cartography for surgeons, who can therefore anticipate risks, increase their confidence and achieve safer liver resection. METHODS: In an experimental prospective cohort study, ten consecutive patients admitted for hepatectomy to three European hospitals were selected. Liver structures (portal veins, hepatic veins, tumours and parenchyma) were segmented from a recent computed tomography (CT) study of each patient. The surgeon planned the resection preoperatively and read the Resection Map as reference guidance during the procedure. Objective (amount of bleeding, tumour resection margin and operating time) and subjective parameters were retrieved after each case. RESULTS: Three different surgeons operated on seven patients with the navigation aid of the Resection Map. Veins displayed in the Resection Map were identified during the surgical procedure in 70.1% of cases, depending mainly on size. Surgeons were able to track resection progress and experienced improved orientation and increased confidence during the procedure. CONCLUSIONS: The Resection Map is a pragmatic solution to enhance the orientation and confidence of the surgeon. Further studies are needed to demonstrate improvement in patient safety.

Two-phase active contour method for semiautomatic segmentation of the heart and blood vessels from MRI images for 3D visualization.

The paper presents an active-contour segmentation method for 2D structures in MR images. The method combines two approaches to active contour segmentation, known as balloons and snakes. This makes the method shape independent and accurate. New anti-tangling features were introduced to improve segmentation of very complex object shapes, e.g. the left ventricle with papillary muscles. The method was applied to segment all large structures in the cardiovascular system and its outcome was used for 3D visualization.