Fully 3D Monte Carlo image reconstruction in SPECT using functional regions

Image reconstruction in Single Photon Emission Computed Tomography (SPECT) is affected by physical effects such as photon attenuation, Compton scatter and detector response. These effects can be compensated for by modeling the corresponding spread of photons in 3D within the system matrix used for tomographic reconstruction. The fully 3D Monte Carlo (F3DMC) reconstruction technique consists in calculating this system matrix using Monte Carlo simulations. The inverse problem of tomographic reconstruction is then solved using conventional iterative algorithms such as maximum likelihood expectation maximization (MLEM). Although F3DMC has already shown promising results, its use is currently limited by two major issues: huge size of the fully 3D system matrix and long computation time required for calculating a robust and accurate system matrix. To address these two issues, we propose to calculate the F3DMC system matrix using a spatial sampling matching the functional regions to be reconstructed. In this approach, different regions of interest can be reconstructed with different spatial sampling. For instance, a single value is reconstructed for a functional region assumed to contain uniform activity. To assess the value of this approach, Monte Carlo simulations have been performed using GATE. Results suggest that F3DMC reconstruction using functional regions improves quantitative accuracy compared to the F3DMC reconstruction method proposed so far. In addition, it considerably reduces disk space requirement and duration of the simulations needed to estimate the system matrix. The concept of functional regions might therefore make F3DMC reconstruction practically feasible.Comment: 6 pages, 3 figures, 3rd International Conference on maging Technologies in Biomedical Sciences : ITBS2005, Milos Island, Greece, 25-28 september 2005, submitted to NIM

Hong Kong domestic health spending: financial years 1989/90 to 2005/06

This report presents the latest estimates of Hong Kong domestic health spending between fiscal years 1989/90 and 2005/06, cross-stratified and categorised by financing source, provider, and function on an annual basis. In fiscal year 2005/06, total health expenditure was HK$71 557 million. In real terms, it grew 6.5$71 557 million total health expenditure in 2005/06, HK$68 810 million (96.2$2746 million (3.8%) on capital expenses (ie investment in medical facilities). Services of curative care accounted for the largest share (67.3%) and were made up of ambulatory services (35.7%), in-patient services (27.7%), day patient hospital services (3.4%), and home care (0.6%). The second largest share was spending on medical goods outside the patient care setting (10.8%). In terms of health care providers, hospitals (44.0%) accounted for the largest share of total health expenditure in 2005/06, followed by providers of ambulatory health care (31.4%). We observed a system-wide trend towards service consolidation at institutions (as opposed to free-standing ambulatory clinics, most of which are staffed by solo practitioners). Not taking capital expenses (ie investment in medical facilities) into account, public current expenditure on health amounted to HK$34 849 million (50.6$33 961 million) was mostly incurred at providers of ambulatory health care (55.8%). This reflects the mixed health care economy of Hong Kong, where public hospitals generally account for about 90% of total bed-days and private doctors (including western and Chinese medicine practitioners) provide about 70% of out-patient care. Although both public and private spending were mostly expended on personal health care services and goods (93.0%), the patterns of distribution among functional categories differed. Public expenditure was targeted at in-patient care (53.7%) and substantially less on out-patient care (24.6%), especially low-intensity first-contact care. In comparison, private spending was concentrated on out-patient care (49.9%), followed by medical goods outside the patient care setting (22.0%) and in-patient care (19.0%). Compared to countries of the Organisation for Economic Co-operation and Development, Hong Kong has devoted a relatively low percentage of gross domestic product on health services in the last decade. As a share of total spending, public funding (either general government revenue or social security funds) was also lower than in most comparably developed economies, although commensurate with its public revenue collection base.published_or_final_versio

Quantitative evaluation of the effect of attenuation correction in SPECT images with CT-derived attenuation

In this study, we assessed the importance of attenuation correction by quantitative evaluation of errors associated with attenuation in myocardial SPECT in a phantom study. To do attenuation correction we use an attenuation map derived from X-ray CT data. The succession of attenuation correction highly depends on high quality of attenuation maps. CT derived attenuation map in related to non-uniform attenuation correction is used to do transmission dependent scatter correction. The OSEM algorithm with attenuation model was developed and used for attenuation correction during image reconstruction. Finally a comparison was done between reconstructed images using our OSEM code and analytical FBP method. The results of measurements show that: Our programs are capable to reconstruct SPECT images and correct the attenuation effects. Moreover to evaluate reconstructed image quality before and after attenuation correction we applied a famous approach using Image Quality Index. Attenuation correction increases the quality and quantity factors in both methods. This increasing is independent of activity in quantity factor and decrease with activity in quality factor. Both quantitative and qualitative of SPECT images were improved by attenuation correction. In both OSEM and FBP the activity ratio of heart phantom in comparison with the markers was very increased. So the attenuation correction in fat patients and low activity is recommended. Attenuation correction with CT images and OSEM reconstruction in the condition of complete registration yields superior results

Generation and detection of Terahertz radiation by Field Effect Transistors

This is a brief overview of the main physical ideas for application of field effect transistors for generation and detection of TeraHertz radiation. Resonant frequencies of the two-dimensional plasma oscillations in FETs increase with the reduction of the channel dimensions and reach the THz range for sub-micron gate lengths. When the mobility is high enough, the dynamics of a short channel FET at THz frequencies is dominated by plasma waves. This may result, on the one hand, in a spontaneous generation of plasma waves by a dc current and on the other hand, in a resonant response to the incoming radiation. In the opposite case, when plasma oscillations are overdamped, the FET can operate as an efficient broadband THz detector.Comment: 10 pages, 3 figure

N=1, D=3 Superanyons, osp(2|2) and the Deformed Heisenberg Algebra

We introduce N=1 supersymmetric generalization of the mechanical system describing a particle with fractional spin in D=1+2 dimensions and being classically equivalent to the formulation based on the Dirac monopole two-form. The model introduced possesses hidden invariance under N=2 Poincar\'e supergroup with a central charge saturating the BPS bound. At the classical level the model admits a Hamiltonian formulation with two first class constraints on the phase space $T^*(R^{1,2})\times {\cal L}^{1|1}$, where the K\"ahler supermanifold ${\cal L}^{1|1}\cong OSp(2|2)/U(1|1)$ is a minimal superextension of the Lobachevsky plane. The model is quantized by combining the geometric quantization on ${\cal L}^{1|1}$ and the Dirac quantization with respect to the first class constraints. The constructed quantum theory describes a supersymmetric doublet of fractional spin particles. The space of quantum superparticle states with a fixed momentum is embedded into the Fock space of a deformed harmonic oscillator.Comment: 23 pages, Late

Influence of age, gender and delay on overtaking dynamics

"This paper is a preprint of a paper submitted to [journal] and is subject to Institution of Engineering and Technology Copyright. If accepted, the copy of record will be available at IET Digital Library"Overtaking is one of the most dangerous manoeuvres on two-lane rural highways. The most influential factors are related to drivers, so ITS and assistance systems are not yet common. This research is based on experimental data of overtaking manoeuvres collected using an instrumented passenger car, equipped with four cameras, laser rangefinders and a global positioning service (GPS) tracker. This vehicle was driven along four different road segments in the surroundings of Valencia (Spain) at a speed slightly slower than the operating speed of each segment. Overtaking time and speeds were measured. Unlike previous work, the influence of human factor was also considered. Age and gender of overtaking driver, as well as time spent following were used to characterise this influence. More than 200 manoeuvres were recorded and the influence of driver characteristics and delay on gap acceptance, manoeuvre duration and speed differences have been analysed. Results show differences in behaviour between age and gender groups, since young male overtaking drivers have shown a more aggressive behaviour. Overtaking times were around 1 s lower than other drivers, whereas average speed difference was 4 km/h higher. Collected data and their analysis have provided a basis to review design criteria and to develop future assistance systems.Authors would like to thank Spanish Ministry of Economy and Competitiveness that subsidizes the research project with reference code TRA2010-21736. Authors thank also Spanish General Traffic Directorate, Spanish Ministry of Public Works and Valencia Regional Governance for their collaboration during field study.Llorca García, C.; García García, A.; Moreno Chou, AT.; Pérez Zuriaga, AM. (2013). Influence of age, gender and delay on overtaking dynamics. IET Intelligent Transport Systems. 7(2):174-181. https://doi.org/10.1049/iet-its.2012.0147S17418172Farah, H. (2011). Age and Gender Differences in Overtaking Maneuvers on Two-Lane Rural Highways. Transportation Research Record: Journal of the Transportation Research Board, 2248(1), 30-36. doi:10.3141/2248-04Hassan, Y., Easa, S. M., & El Halim, A. O. A. (1996). Passing sight distance on two-lane highways: Review and revision. Transportation Research Part A: Policy and Practice, 30(6), 453-467. doi:10.1016/0965-8564(95)00032-1Wang, Y., & Cartmell, M. P. (1998). New Model for Passing Sight Distance on Two-Lane Highways. Journal of Transportation Engineering, 124(6), 536-545. doi:10.1061/(asce)0733-947x(1998)124:6(536)Polus, A., Livneh, M., & Frischer, B. (2000). Evaluation of the Passing Process on Two-Lane Rural Highways. Transportation Research Record: Journal of the Transportation Research Board, 1701(1), 53-60. doi:10.3141/1701-07Carlson, P., Miles, J., & Johnson, P. (2006). Daytime High-Speed Passing Maneuvers Observed on Rural Two-Lane, Two-Way Highway: Findings and Implications. Transportation Research Record: Journal of the Transportation Research Board, 1961, 9-15. doi:10.3141/1961-02Hegeman, G., Tapani, A., & Hoogendoorn, S. (2009). Overtaking assistant assessment using traffic simulation. Transportation Research Part C: Emerging Technologies, 17(6), 617-630. doi:10.1016/j.trc.2009.04.010El Zarif, J., Hobeika, A., & Rakha, H. (2003). Evaluating a Detection and Warning System to Deter No-Passing Zone Violations. Journal of Transportation Engineering, 129(6), 590-599. doi:10.1061/(asce)0733-947x(2003)129:6(590)Llorca, C., & García, A. (2011). Evaluation of Passing Process on Two-Lane Rural Highways in Spain with New Methodology Based on Video Data. Transportation Research Record: Journal of the Transportation Research Board, 2262(1), 42-51. doi:10.3141/2262-0

Modelling vehicles acceleration during overtaking manoeuvres

[EN] Abstract: Overtaking manoeuvre is a key issue for two-lane rural roads. These roads should provide sufficient overtaking sight distance (OSD) at certain locations to allow faster vehicles to pass slower ones. However, overtaking requires occupying the opposing lane, which represents a serious safety concern. Severity of overtaking related crashes is very high, compared with other manoeuvres. The development of advanced driver assistance systems (ADAS) for overtaking is being a complex task. Only few systems have been developed, but are not still in use. This research incorporated accurate data of real manoeuvres to improve the knowledge of the phenomenon. The trajectory of the overtaking vehicles on the left lane was observed. An instrumented vehicle measured the overtaking time and distance, the abreast position, and the initial and final speed of 180 drivers that passed it during a field experiment. Six different kinematic models (such as uniform acceleration or linear variation of acceleration) were calibrated. Generally, drivers started to accelerate before changing to the opposing lane. These models may be applied to ADAS, to estimate OSD and to improve microsimulation models.Part of this research was included in the project 'Desarrollo de modelos de distancias de visibilidad de adelantamiento', with reference code TRA2010-21736 and subsidised by the Spanish Ministery of Economy and Competitivity. The authors also thank Prof Dr Sayed, from University of British Columbia, for his valuable review.Llorca Garcia, C.; Moreno, AT.; García García, A. (2016). Modelling vehicles acceleration during overtaking manoeuvres. IET Intelligent Transport Systems. 10(3):206-215. https://doi.org/10.1049/iet-its.2015.0035S206215103Gray, R., & Regan, D. M. (2005). Perceptual Processes Used by Drivers During Overtaking in a Driving Simulator. Human Factors: The Journal of the Human Factors and Ergonomics Society, 47(2), 394-417. doi:10.1518/0018720054679443Basilio, N., Morice, A. H. P., Marti, G., & Montagne, G. (2015). High- and Low-Order Overtaking-Ability Affordances. Human Factors: The Journal of the Human Factors and Ergonomics Society, 57(5), 879-894. doi:10.1177/0018720815583581Morice, A. H. P., Diaz, G. J., Fajen, B. R., Basilio, N., & Montagne, G. (2015). An Affordance-Based Approach to Visually Guided Overtaking. Ecological Psychology, 27(1), 1-25. doi:10.1080/10407413.2015.991641Farah, H., Bekhor, S., & Polus, A. (2009). Risk evaluation by modeling of passing behavior on two-lane rural highways. Accident Analysis & Prevention, 41(4), 887-894. doi:10.1016/j.aap.2009.05.006Hassan, Y., Easa, S. M., & El Halim, A. O. A. (1996). Passing sight distance on two-lane highways: Review and revision. Transportation Research Part A: Policy and Practice, 30(6), 453-467. doi:10.1016/0965-8564(95)00032-1Wang, Y., & Cartmell, M. P. (1998). New Model for Passing Sight Distance on Two-Lane Highways. Journal of Transportation Engineering, 124(6), 536-545. doi:10.1061/(asce)0733-947x(1998)124:6(536)Sparks, G. A., Neudorf, R. D., Robinson, J. B. L., & Good, D. (1993). Effect of Vehicle Length on Passing Operations. Journal of Transportation Engineering, 119(2), 272-283. doi:10.1061/(asce)0733-947x(1993)119:2(272)Hanley, P. F., & Forkenbrock, D. J. (2005). Safety of passing longer combination vehicles on two-lane highways. Transportation Research Part A: Policy and Practice, 39(1), 1-15. doi:10.1016/j.tra.2004.09.001Khoury, J. E., & Hobeika, A. G. (2012). Integrated Stochastic Approach for Risk and Service Estimation: Passing Sight Distance Application. Journal of Transportation Engineering, 138(5), 571-579. doi:10.1061/(asce)te.1943-5436.0000366Jenkins, J. M., & Rilett, L. R. (2004). Application of Distributed Traffic Simulation for Passing Behavior Study. Transportation Research Record: Journal of the Transportation Research Board, 1899(1), 11-18. doi:10.3141/1899-02Rakha, H., Ahn, K., & Trani, A. (2004). Development of VT-Micro model for estimating hot stabilized light duty vehicle and truck emissions. Transportation Research Part D: Transport and Environment, 9(1), 49-74. doi:10.1016/s1361-9209(03)00054-3Polus, A., Livneh, M., & Frischer, B. (2000). Evaluation of the Passing Process on Two-Lane Rural Highways. Transportation Research Record: Journal of the Transportation Research Board, 1701(1), 53-60. doi:10.3141/1701-07Harwood, D. W., Gilmore, D. K., & Richard, K. R. (2010). Criteria for Passing Sight Distance for Roadway Design and Marking. Transportation Research Record: Journal of the Transportation Research Board, 2195(1), 36-46. doi:10.3141/2195-05Hegeman, G., Tapani, A., & Hoogendoorn, S. (2009). Overtaking assistant assessment using traffic simulation. Transportation Research Part C: Emerging Technologies, 17(6), 617-630. doi:10.1016/j.trc.2009.04.010Milanés, V., Llorca, D. F., Villagrá, J., Pérez, J., Fernández, C., Parra, I., … Sotelo, M. A. (2012). Intelligent automatic overtaking system using vision for vehicle detection. Expert Systems with Applications, 39(3), 3362-3373. doi:10.1016/j.eswa.2011.09.024Isermann, R., Mannale, R., & Schmitt, K. (2012). Collision-avoidance systems PRORETA: Situation analysis and intervention control. Control Engineering Practice, 20(11), 1236-1246. doi:10.1016/j.conengprac.2012.06.003Petrov, P., & Nashashibi, F. (2014). Modeling and Nonlinear Adaptive Control for Autonomous Vehicle Overtaking. IEEE Transactions on Intelligent Transportation Systems, 15(4), 1643-1656. doi:10.1109/tits.2014.2303995Llorca, C., & García, A. (2011). Evaluation of Passing Process on Two-Lane Rural Highways in Spain with New Methodology Based on Video Data. Transportation Research Record: Journal of the Transportation Research Board, 2262(1), 42-51. doi:10.3141/2262-05Llorca, C., Moreno, A. T., García, A., & Pérez-Zuriaga, A. M. (2013). Daytime and Nighttime Passing Maneuvers on a Two-Lane Rural Road in Spain. Transportation Research Record: Journal of the Transportation Research Board, 2358(1), 3-11. doi:10.3141/2358-01Llorca, C., Moreno, A. T., Pérez-Zuriaga, A. M., & García, A. (2013). Influence of age, gender and delay on overtaking dynamics. IET Intelligent Transport Systems, 7(2), 174-181. doi:10.1049/iet-its.2012.0147Khoury, J. E., & Hobeika, A. (2007). Incorporating Uncertainty into the Estimation of the Passing Sight Distance Requirements. Computer-Aided Civil and Infrastructure Engineering, 22(5), 347-357. doi:10.1111/j.1467-8667.2007.00491.xRakha, H., Snare, M., & Dion, F. (2004). Vehicle Dynamics Model for Estimating Maximum Light-Duty Vehicle Acceleration Levels. Transportation Research Record: Journal of the Transportation Research Board, 1883(1), 40-49. doi:10.3141/1883-05Fitzpatrick, K., Chrysler, S. T., & Brewer, M. (2012). Deceleration Lengths for Exit Terminals. Journal of Transportation Engineering, 138(6), 768-775. doi:10.1061/(asce)te.1943-5436.000038

Ablative therapy for people with localised prostate cancer : a systematic review and economic evaluation

The research reported in this issue of the journal was funded by the HTA programme as project number 10/136/01. The contractual start date was in April 2012. The draft report began editorial review in October 2013 and was accepted for publication in April 2014. The authors have been wholly responsible for all data collection, analysis and interpretation, and for writing up their work. The HTA editors and publisher have tried to ensure the accuracy of the authors’ report and would like to thank the reviewers for their constructive comments on the draft document. However, they do not accept liability for damages or losses arising from material published in this report. Acknowledgements We thank l the people recruited from the local UCAN for providing valuable consumer insight and advice through their participation as members of the project focus group: - Mark Emberton (Professor of Interventional Oncology), Damian Greene (consultant urologist), Axel Heidenreich (Professor and Director of Department of Urology), Christoph von Klot (specialist in brachytherapy), Roger Kockelbergh (BAUS chairman and Clinical Director of Urology) and Axel Merserburger (Deputy Clinical Director of Urology and Urologic Oncology) for providing their clinical expertise as members of the project advisory group - Edgar Paez (consultant urologist) and Gill Lawrence (Head of Radiotherapy Physics) for providing a list of staff time by grade and specialty involved in EBRT - Debbie Bennett (Radiotherapy Service Manager) for providing estimates for the expected number of uses for EBRT - Ian Pedley (clinical director/clinical oncologist) and Gill Lawrence for providing a list of all resource inputs relevant to brachytherapy - Steve Locks (Consultant Clinical Scientist in Radiotherapy) for providing a list of reusable equipment and consumables used during brachytherapy, along with their unit costs - Sue Asterling (urology research nurse) and Mark Kelly (Acting Divisional General Manager – Theatres) for providing a list of all resource inputs relevant to cryotherapy - Lara Kemp for providing secretarial support. The Health Services Research Unit is core funded by the Chief Scientist Office of the Scottish Government Health Directorates.Peer reviewedPublisher PD