Vladimir Bashkirov

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Determination of the Bragg peak position in proton therapy requires accurate knowledge of the electron density and ratio of effective atomic number and mass (Z/A) of the body tissues traversed. While the Z/A ratio is fairly constant for human tissues, the density of tissues varies significantly. One possibility to obtain accurate electron density(More)
—Proton computed tomography (pCT) has the potential to improve the accuracy of dose calculations for proton treatment planning, and will also be useful for pretreatment verification of patient positioning relative to the proton beam. A design study was performed to define the optimal approach to a pCT system based on specifications for applications in(More)
PURPOSE The authors present a calibration method for a prototype proton computed tomography (pCT) scanner. The accuracy of these measurements depends upon careful calibration of the energy detector used to measure the residual energy of the protons that passed through the object. METHODS A prototype pCT scanner with a cesium iodide (CsI(Tl)) crystal(More)
–As part of a program to investigate the feasibility of proton computed tomography, the most likely path (MLP) of protons inside an absorber was measured in a beam experiment using a silicon strip detector setup with high position and angular resolution. The locations of 200 MeV protons were measured at three different absorber depth of PMMA (3.75, 6.25 and(More)
Exclusive production of 0 and J== mesons in e + p collisions has been studied with the ZEUS detector in the kinematic range 0:25 < Q 2 < 50 GeV 2 , 20 < W < 167 GeV for the 0 data and 2 < Q 2 < 40 GeV 2 , 50 < W < 150 GeV for the J== data. Cross sections for exclusive 0 and J== production have been measured as a function of Q 2 , W and t. The spin-density(More)
Using the ZEUS detector at HERA, we have studied the reaction e + p ! e + X for Q 2 > 5000 GeV 2 with a 20:1 pb ?1 data sample collected during the years 1994 to 1996. For Q 2 below 15000GeV 2 , the data are in good agreement with Standard Model expectations. For Q 2 > 35000 GeV 2 , two events are observed while 0:145 0:013 events are expected. A(More)
In deep inelastic neutral current scattering of positrons and protons at the center of mass energy of 300 GeV, we observe, with the ZEUS detector, events with a high energy neutron produced at very small scattering angles with respect to the proton direction. The events constitute a fixed fraction of the deep inelastic, neutral current event sample(More)
The e + p neutral-current deep inelastic scattering diierential cross-sections dd=dQ 2 , for Q 2 > 400 GeV 2 , dd=dx and dd=dy, for Q 2 > 400, 2500 and 10000 GeV 2 , have been measured with the ZEUS detector at HERA. The data sample of 47.7 pb ?1 was collected at a center-of-mass energy of 300 GeV. The cross-section, dd=dQ 2 , falls by six orders of(More)
Proton radiography has applications in patient alignment and verification procedures for proton beam radiation therapy. In this paper, we report an experiment which used 200 MeV protons to generate proton energy-loss and scattering radiographs of a hand phantom. The experiment used the first-generation proton computed tomography (CT) scanner prototype,(More)
Proton computed tomography (pCT) has the potential to improve the accuracy of proton treatment planning, which is currently based on x-ray computed tomography (xCT). However, at this time no method exists for pCT to selectively increase the contrast of tumor tissues with respect to normal tissues. One possibility to achieve this goal is to bind(More)