Economic Evaluation of Positron Emission Tomography (PET) in Non Small Cell Lung Cancer (NSCLC), CHERE Working Paper 2007/6

Background: There are several perceived benefits from introducing positron emission tomography (PET) scanning into the staging of non small lung cancer (NSCLC). However, its greatest primary benefit is the role it can potential perform in reducing the number of unnecessary diagnostic examinations and futile surgeries. Objectives: To evaluate the economic impact and cost effectiveness of PET scanning in the management of potentially operable NSCLC patients using a cost-utility model. Methods: A literature review was conducted to find relevant studies and appropriate parameters to construct a decision model. Two strategies were compared. The first strategy was a conventional work up (CWU) consisting of an x-ray, a chest computer tomography (CT) scan and brochoscopy; the second strategy consisted of a CWU plus a whole body PET scan. These two strategies were applied to two sub-groups of NSCLC patients; those that had received a positive result on their CT scan and those that got a negative result on their CT scan. The cost-effectiveness of each strategy was dependent on a number of variables that were taken from a literature review. Costs were based on the Australian diagnostic related groups, a cost calculation for a chemotherapy course and values obtained from the literature. The life expectancy and utility scores were also taken from the literature and combined to create an incremental quality adjusted life year (QALY) value for PET for each of the patient groups. Results: The mean costs in CT negative and CT positive patients were lower in the CWU strategy, costing $A 20,427 and$A 23,578 per patient respectively compared to the PET strategy ($A 20,826 and$A 24,083 per patient respectively). The mean QALYs for both the CT positive and CT negative patients were higher in PET with 2.91 and 2.11 respectively compared to the CWU of 2.88 and 2.09. The incremental cost effectiveness ratio (ICER) for the CT negative strategy was $A 14,581 and$A 52,039 for the CT positive strategy. Conclusion: The PET strategy in CT negative and CT positive patients appears to be cost effective, however, there is much uncertainty surrounding this base result, particularly in CT positive patients.PET, non-small-cell lung cancer, economic evaluation

On the behavior of micro-spheres in a hydrogen pellet target

A pellet target produces micro-spheres of different materials, which are used as an internal target for nuclear and particle physics studies. We will describe the pellet hydrogen behavior by means of fluid dynamics and thermodynamics. In particular one aim is to theoretically understand the cooling effect in order to find an effective method to optimize the working conditions of a pellet target. During the droplet formation the evaporative cooling is best described by a multi-droplet diffusion-controlled model, while in vacuum, the evaporation follows the (revised) Hertz-Knudsen formula. Experimental observations compared with calculations clearly indicated the presence of supercooling, the effect of which is discussed as well.Comment: 22 pages, 8 figures (of which two are significantly compressed for easier download

Ultra High Energy Cosmic Rays

The current status of Ultra High Energy Cosmic Rays (UHECR) is reviewed, with emphasis given to theoretical interpretation of the observed events. The galactic and extragalactic origin, in case of astrophysical sources of UHE particles, have the problems either with acceleration to the observed energies or with the fluxes and spectra. Topological defects can naturally produce particles with energies as observed and much higher, but in most cases fail to produce the observed fluxes. Cosmic necklaces and monopole-antimonopole pairs are identified as most plausible sources, which can provide the observed flux and spectrum. The relic superheavy particles are shown to be clustering in the Galactic halo, producing UHECR without Greisen-Zatsepin-Kuzmin cutoff. The Lightest Supersymmetric Particles are discussed as UHE carriers in the Universe.Comment: 10 pages text, 6 ps figures, 1 jpeg figure. Invited talk at TAUP-9

Probing Physics at Extreme Energies with Cosmic Ultra-High Energy Radiation

The highest energy cosmic rays observed possess macroscopic energies and their origin is likely to be associated with the most energetic processes in the Universe. Their existence triggered a flurry of theoretical explanations ranging from conventional shock acceleration to particle physics beyond the Standard Model and processes taking place at the earliest moments of our Universe. Furthermore, many new experimental activities promise a strong increase of statistics at the highest energies and a combination with gamma-ray and neutrino astrophysics will put strong constraints on these theoretical models. We give an overview over this quickly evolving research field with focus on testing new particle physics.Comment: 12 latex pages, 2 postscript figures included; based on invited talk at the WHEPP-7 Conference, Allahabad, India (January, 2002

The high energy cosmic ray spectrum from relic particle decay

It has been speculated that the recently detected ultra-high energy cosmic rays may originate from the decays of relic particles with mass of order $10^{12}$ GeV clustered in the halo of our Galaxy. This hypothesis can be tested through forthcoming measurements of the spectra of both high energy cosmic nucleons and neutrinos, which are determined in this model by the physics of QCD fragmentation, with no astrophysical uncertainties. We evolve fragmentation spectra measured at LEP energies up to the scale of the decaying particle mass by numerical solution of the DGLAP equations. This enables incorporation of the effects of supersymmetry on the development of the cascade and we also allow for decays into many-particle states. The calculated spectral shape agrees well with present cosmic ray data beyond the Greisen-Zatsepin-Kuzmin energy.Comment: 30 pages (revtex), 12 figures (eps); Small revisions; Accepted for publicatio

Cosmic Necklaces and Ultrahigh Energy Cosmic Rays

Cosmic necklaces are hybrid topological defects consisting of monopoles and strings, with two strings attached to each monopole. We argue that the cosmological evolution of necklaces may significantly differ from that of cosmic strings. The typical velocity of necklaces can be much smaller than the speed of light, and the characteristic scale of the network much smaller than the horizon. We estimate the flux of high-energy protons produced by monopole annihilation in the decaying closed loops. For some reasonable values of the parameters it is comparable to the observed flux of ultrahigh-energy cosmic rays.Comment: 10 pages, Revtex, 1 figur

On the nature of cosmic rays above the Greisen--Zatsepin--Kuz'min cut off

A re-examination of the atmospheric cascade profile of the highest energy cosmic ray is presented. The study includes air-shower simulations considering different cross sections, particle multiplicity and variation of the hadronic-event-generator to model interactions above 200 GeV. The analysis provides evidence that a medium mass nucleus primary reproduces the shower profile quite well. This result does not support the idea, increasingly popular at present, that the highest energy particles are protons, derived from the decay of supermassive relic particles. On the other hand, we show that debris of relativistic super-heavy nuclei, which can survive a 100 Mpc journey through the primeval radiation are likely to generate such a kind of cascade.Comment: Revised version, improvements per referee's suggestions. To be published in Phys. Lett.

Strongly Interacting Neutrinos and the Highest Energy Cosmic Rays

Cosmic rays of energies larger than the Greisen-Zatsepin-Kuzmin (GZK) cutoff may be neutrinos if they acquire strong interactions due to a ``precocious unification'' of forces. A scenario for this to happen is outlined. There is no contradiction with precision measurements carried out at LEP and SLAC. Observable consequences at LHC and future neutrino detectors are discussed.Comment: 9 pages, LaTeX2e, no macros, 2 eps. figures. Uses epsf.te

Ultra High Energy Cosmic Rays from Cosmological Relics

The current status of origin of Ultra High Energy Cosmic Rays (UHECR) is reviewed, with emphasis given to elementary particle solutions to UHECR problem, namely to Topological Defects and Super-Heavy Dark Matter (SHDM) particles. The relic superheavy particles are very efficiently produced at inflation. Being protected by gauge discrete symmetries, they can be long lived. They are clustering in the Galactic halo, producing thus UHECR without Greisen-Zatsepin-Kuzmin cutoff. Topological Defects can naturally produce particles with energies as observed and much higher, but in most cases fail to produce the observed fluxes. Cosmic necklaces, monopoles connected by strings and vortons are identified as most plausible sources. The latter two of them are also clustering in the halo and their observational predictions are identical to those of SHDM particles.Comment: Invited talk at TAUP-99, Paris, September 6 - 10, 1999. Several references are adde