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The development of total-body PET scanners is of growing interest in the PET community. Investigation into the imaging properties of a hypothetical extended axial field-of-view (AFOV) GE Healthcare SiPM-based Discovery MI (DMI) system architecture has not yet been performed. In this work, we assessed its potential as a whole-body scanner using Monte Carlo simulations. The aim of this work was to (1) develop and validate a Monte Carlo model of a four-ring scanner and (2) extend its AFOV up to 2 m to evaluate performance gain through NEMA-based evaluation.The DMI four-ring geometry and its pulse digitization scheme were modeled within the GATE Monte Carlo platform using published literature. The GATE scanner model was validated by comparing results against published NEMA performance measurements. Following the validation of the four-ring model, the model was extended to simulate 8-, 20-, 30-, and 40-ring systems. Spatial resolution, sensitivity, NECR, and scatter fraction were characterized with modified NEMA NU-2 2018 standards; however, the image quality measurements were not acquired due to computational limitations. Spatial resolutions were simulated for all scanner ring configurations using point sources to examine the effects of parallax errors. NEMA count rates were estimated using a standard 70 cm scatter phantom and an extended version of scatter phantom of length 200 cm with (1-800) MBq ofThe average FWHM of the radial/tangential/axial spatial resolution reconstructed with filtered back-projection at 1 and 10 cm from the scanner center were 3.94/4.10/4.41 mm and 5.29/4.89/5.90 mm for the four-ring scanner. Sensitivity was determined to be 14.86 cps/kBq at the center of the FOV for the four-ring scanner using a 70 cm line source. Sensitivity enhancement up to 21-fold and 60-fold were observed for 1 and 2 m AFOV scanners compared to four-ring scanner using a 200 cm long line source. Spatial resolution simulations in a 2 m AFOV scanner suggest a maximum degradation of ∼23.8% in the axial resolution compared to the four-ring scanner. However, the transverse resolution was found to be relatively constant when increasing the axial acceptance angle up to ±70°. The peak NECR was 212.92 kcps at 22.70 kBq/ml with a scatter fraction of 38.9% for a four-ring scanner with a 70 cm scatter phantom. Comparison of peak NECR using the 200 cm long scatter phantom relative to the four-ring scanner resulted in a NECR gain of 15 for the 20-ring and 28 for the 40-ring geometry. Spatial resolution, sensitivity, and scatter fraction showed an agreement within ∼7% compared with published measured values.The four-ring DMI scanner simulation was successfully validated against published NEMA measurements. Sensitivity and NECR performance of extended 1 and 2 m AFOV scanners based upon the DMI architecture were subsequently simulated. Increases in sensitivity and count-rate performance are consistent with prior simulation studies utilizing extensions of the Siemens mCT architecture and published NEMA measurements with the uEXPLORER system.

Cancer is the second most leading cause of deaths in the world and has been manifested by various hallmarks including uncontrolled cell proliferation, increased cell survival, abnormal angiogenesis, eluding of antitumor immunity and acquisition of metabolic processes unique to cancers. Interestingly, mTOR signaling is found to be associated with all of these hallmarks which makes it the most appropriate choice for target therapies against cancer. Inhibition of the target protein by peptides designed by using the interfacial amino acids of its interacting partner is one of the approaches of target therapies. The same approach has been engaged here to inhibit association of the mTOR kinase and RHEB. The sequential amino acids of the mTOR kinase were utilized to design three different native peptides which were further modified by incorporating evolutionary changes as the mutations. All the peptides were tested for their affinity with the RHEB by performing protein-peptide docking on the HADDOCK 2.4 docking interface and the binding energy calculation on the FoldX5.0 interface. Also, the interactions were analyzed using the ligplot+ tool. The peptide H2P1 and H3P1 showed good binding energies (-14.28 kcal/mol and − 14.53 kcal/mol, respectively) in comparison to the entire mTOR-RHEB complex (-15.83 kcal/mol). This was also supported by a good number of Hydrogens bonds and other positive interactions. All these evidences support their potency to interrupt the mTORC1 signaling which can be further established based on these shreds of evidences.

Purpose This study aims to experimentally validate the Monte Carlo generated absorbed doses from the beta particles emitted by 90 Y and 177 Lu using radiochromic EBT3 film-based dosimetry. Methods Line sources of 90 Y and 177 Lu were inserted longitudinally through blocks of low-density polyethylene and tissue-equivalent slabs of cortical bone and lung equivalent plastics. Radiochromic film (Gafchromic EBT3) was laser cut to accommodate orthogonal line sources of radioactivity, and the film was sandwiched intimately between the rectangular blocks to achieve charged particle equilibrium. Line sources consisted of plastic capillary tube of length (13 ± 0.1) cm, with 0.42-mm inner diameter and a wall thickness of 0.21 mm. 90 Y line sources were prepared from a solution of dissolved 90 Y resin microspheres. 177 Lu line sources were prepared from an aliquot of 177 Lu-DOTATATE. Film exposures were conducted for durations ranging from 10 min to 38 h. Radiochromic film calibration was performed by irradiation with 6-MV-bremsstrahlung x rays from a calibrated linear accelerator, in accordance with literature recommendations. Experimental geometries were precisely simulated within the GATE Monte Carlo toolkit, which has previously been used for the generation of dose point kernels. Results The mean percentage difference between measured and simulated absorbed doses were 5.04% and 7.21% for 90 Y and 177 Lu beta absorbed dose in the range of (0.1-10) Gy. Additionally, 1D gamma analysis using a local 10%/1 mm gamma criterion was performed to compare the absorbed dose distributions. The percentage of measurement points passing the gamma criterion, averaged over all tests, was 93.5%. Conclusions We report the experimental validation of Monte Carlo derived beta absorbed dose distributions for 90 Y and 177 Lu, solidifying the validity of using Monte Carlo-based methods for estimating absorbed dose from beta emitters. Overall, excellent agreement was observed between the experimental beta absorbed doses in the linear region of the radiochromic film and the GATE Monte Carlo simulations demonstrating that radiochromic film dosimetry has sufficient sensitivity and spatial resolution to be used as a tool for measuring beta decay absorbed dose distributions.

The purpose of this work was to perform an independent and National Institute of Standards and Technology-traceable activity measurement of

In recent years the use of beta-emitting radiopharmaceuticals for cancer therapy has expanded rapidly following development of therapeutics for neuroendocrine tumors, prostate cancer, and other oncologic malignancies. One emerging beta-emitting radioisotope of interest for therapy is

Annual modulation of $\ensuremath{\gamma}$ rays from $(\ensuremath{\alpha},\ensuremath{\gamma})$ reactions induced by the $\ensuremath{\alpha}$ activity of radon and its daughters was reported by Tiwari, Zhang, Mei, and Cushman (TZMC). While Mohr does not contest the measurements themselves, he has commented that unrealistic $(\ensuremath{\alpha},\ensuremath{\gamma})$ cross sections were used in the analysis of the $\ensuremath{\gamma}$-ray flux, and thus the $\ensuremath{\gamma}$-ray fluxes calculated by TZMC are not reliable. We demonstrate that the $(\ensuremath{\alpha},\ensuremath{\gamma})$ cross sections obtained from talys include the energy-broadened cross sections for discrete states in the high-energy tail of the spectra, which are required in order to compare with the angle-integrated and double-differential spectra obtained from a liquid scintillator detector with an energy resolution of only $\ensuremath{\approx}15%$. A comparison with varying ``elwidth'' shows that cross sections indeed are reliable within the energy region (4 to 10 MeV) reported by TZMC, especially for the dominant contribution, which is the aluminum wall of the detector. Any differences in the $(\ensuremath{\alpha},\ensuremath{\gamma})$ cross sections for $^{16}\mathrm{O}$ at the level detailed by Mohr will have negligible effect on the final flux.

The half-life of 67Cu was determined through serial gamma-ray spectrometry measurements of the dominant gamma emission (E γ : 184.6 keV; branching ratio: 48.7%) produced following β- decay. Data were collected consecutively for 1000 s per measurement, with a total of 3063 measurements over the duration of 36 days. The incidence rate for the 184.6 keV gamma-ray was determined from the spectral peak area and duration of each measurement. This rate was then corrected to account for detector dead-time, radioactive decay during each acquisition and drift in the computer clock in comparison to NIST nuclear clock. Least-squares regression analysis was performed to determine the half-life of 67Cu. The result was 61.761 ± 0.004 h, which is the highest precision measurement to date, and marks a 24-fold precision improvement over the current Nuclear Data Sheets value.

In recent years the use of beta-emitting radiopharmaceuticals for cancer therapy has expanded rapidly following development of therapeutics for neuroendocrine tumors, prostate cancer, and other oncologic malignancies. One emerging beta-emitting radioisotope of interest for therapy is 67Cu (t1/2: 2.6 d) due to its chemical equivalency with the widely-established positron-emitting isotope 64Cu (t1/2: 12.7 h). In this work we evaluate both the imaging and dosimetric characteristics of 67Cu, as well as producing the first report of SPECT/CT imaging using 67Cu. To this end, 67Cu was produced by photon-induced reactions on isotopically-enriched 68Zn at the Low-Energy Accelerator Facility (LEAF) of Argonne National Laboratory, followed by bulk separation of metallic 68Zn by sublimation and radiochemical purification by column chromatography. Gamma spectrometry was performed by efficiency-calibrated high-purity germanium (HPGe) analysis to verify absolute activity calibration and establish radionuclidic purity. Absolute activity measurements corroborated manufacturer-recommended dose-calibrator settings and no radionuclidic impurities were observed. Using the Clinical Trials Network anthropomorphic chest phantom, SPECT/CT images were acquired. Medium energy (ME) SPECT collimation was found to provide the best image quality from the primary 185 keV gamma emission of 67Cu. Reconstructed images of 67Cu were similar in quality to images acquired using 177Lu. Recovery coefficients were calculated and compared against quantitative images of 99mTc, 177Lu, and 64Cu within the same anthropomorphic chest phantom. Production and clinical imaging of 67Cu appears feasible, and future studies investigating the therapeutic efficacy of 67Cu-based radiopharmaceuticals are warranted.

We report the generation of dose point kernels for clinically-relevant radionuclide beta decays and monoenergetic electrons in various tissues to understand the impact of tissue type on dose point kernels. Currently available voxel-wise dosimetry approaches using dose point kernels ignore tissue composition and density heterogeneities. Therefore, the study on the impact of tissue type on dose point kernels is warranted. Simulations were performed using the GATE Monte Carlo toolkit, which encapsulates GEANT4 libraries. Dose point kernels were simulated in phantoms of water, compact bone, lung, adipose tissue, blood and red marrow for radionuclides 90Y, 188Re, 32P, 89Sr, 186Re, 153Sm and 177Lu and monoenergetic electrons (0.015-10 MeV). All simulations were performed by assuming an isotropic point source of electrons at the center of a homogeneous spherical phantom. Tissue-specific differences between kernels were investigated by normalizing kernels for effective pathlength. Transport of 20 million particles was found to provide sufficient statistical precision in all simulated kernels. The simulated dose point kernels demonstrate excellent agreement with other Monte Carlo packages. Deviation from kernels reported in the literature did not exceed a 10% global difference, which is consistent with the variability among published results. There are no significant differences between the dose point kernel in water and kernels in other tissues that have been scaled to account for density; however, tissue density predictably demonstrated itself to be a significant variable in dose point kernel distribution.

Annual modulation of $\ensuremath{\gamma}$ rays from ($\ensuremath{\alpha},\ensuremath{\gamma}$) reactions in the Soudan Underground Laboratory was observed using a 12-liter scintillation detector. This significant annual modulation, measured over 4 years, can mimic the signature for dark matter and can also generate potential background events for neutrinoless double-$\ensuremath{\beta}$ decay experiments. The measured annual modulation of the event rate from ($\ensuremath{\alpha},\ensuremath{\gamma}$) reactions is strongly correlated with the time-varying radon concentration observed independently in the laboratory. The $\ensuremath{\alpha}$ flux from radon decay is simulated starting from the measured radon concentration, and the $\ensuremath{\gamma}$-ray flux is determined using the convolution of the $\ensuremath{\alpha}$ flux and the cross sections for ($\ensuremath{\alpha},\ensuremath{\gamma}$) reactions. The calculated $\ensuremath{\gamma}$-ray flux is sufficient to generate the measured event rate that exhibits an annual modulation.

Gravitational radiation from a system of two body, one as test particle and other as black hole (we assume, mi is mass of the test particle and m 2 is mass of black hole in bound orbits (orbital eccentricities e < 1) and E 2 < 1; E is the energy, is calculated with relativistic correction using the method of inertia tensor and multipole formalism. Plots of power versus eccentricity of the bound orbit of first kind are presented, and average total power radiated as a function of eccentricity is plotted according to inertia tensor method. According to multipole formalism the power radiated in gravitational waves from an bound orbit is given by enhancement factor g(n,e) times the function of other parameters is plotted. The calculations apply for arbitrary eccentricity of the relative orbit, assuming orbital velocities are small.

This chapter reviews the support of asynchronous teams utilizing intranet-based mini-case study publication with web-based conferencing The specific situation relates to large groups of one-year full-time MBA students. The chapter reports on this exercise from both pedagogic and groupware perspectives. Implications, and planned future developments of this approach, are reviewed.

This chapter reviews the support of asynchronous teams, initially utilising Intranet-based mini-case study publication with Web-based conferencing. There was subsequent use of Lotus Notes within the same context. The specific situation relates to large groups of one-year full time MBA students. The chapter reports on this exercise from both pedagogic and groupware perspectives. Implications, and planned future developments of this approach, are reviewed.

Department of Sotl Science and Agricultural Chemistry, C. S Azad University of Agriculture and Technology, Kanpur-208 002 Manusript received 10 April1993. accepted 30 June 1993 Potassium for Yield Improvement of Wheat

In the recent past, several herbal drugs have proved their efficacy in decreasing anxiety and tension. Until recently, limited scientific study has been done to prove the clinical importance of these herbal drugs. Geriforte is an indigenous compound commonly advocated for arresting the aging process. This remedy has also been found beneficial in reducing anxiety and stress.-34 diagnosed cases of anxiety neurosis and 24 apparently normal individuals were selected for the present study. After 12 weeks of drug therapy a significant reduction in 5-HT levels was observed. Circulating MAO and GABA showed an increasing trend along with decreased glutamic acid levels after treatment, in the neurotic anxiety cases. Psychological complaints considerably decreased after 12 weeks of therapy. Since Geriforte regulates the altered circulating biogenic amines, this remedy can be advocated as an adjunctive therapy in the management of stress disorders.

In the present study, 51 apparently normal volunteers and 34 clinically established coronary heart disease cases were studied. 21 out of 51 normal, and 16 out 34 coronary heart disease cases were cigarette smokers. The cases were divided in two age groups--20 to 40 years, the younger age group and 41 to 60 years, the older age group. Total serum cholesterol and high-density lipoprotein cholesterol of all the cases were determined. The ratio of total cholesterol to high-density lipoprotein cholesterol was significantly higher in all the smoking normal and coronary heart disease smokers. Hence, the higher levels of total cholesterol to high density lipoprotein cholesterol ratio appears to be one of the important parameters to ascertain the development of coronary heart disease in cigarette smokers.

Department of Chemistry, University of Allahabad, Allahabad-211 002, Uttar Pradesh, India E-mail : kbpandeya@yahoo.com Division of Pharmacology, Indian Institute of Chemical Technology, Hyderabad-500 007, India Manuscript received 04 July 2011, accepted 05 July 2011 α-Glucosidase inhibition and DPPH free radical scavenging by four oxovanadium(IV) complexes of tetradentate Schiff bases, derived from salicylaldehyde/5-bromosalicylaldehyde and ethylenediamine/phenylenediamine (VO-salen, VO-brsalen, VO-salphn and VO-brsalphn), have been screened. Among the four complexes studied, VO-salen shows best α-glucosidase inhibition and also best DPPH free radical scavenging property.