Zobrazeno 1 - 10
of 42
pro vyhledávání: '"Grigor N. Grigorov"'
Publikováno v:
Medical Biophysics Publications
Background and purpose: This study investigated the variations of rectal motion and wall thickness in prostate intensity-modulated radiotherapy using a novel 2D probability density function. To evaluate the impact of the position, thickness, and defo
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::aae003b227e2ff4ecc35b39c6cae6a25
https://ir.lib.uwo.ca/biophysicspub/458
https://ir.lib.uwo.ca/biophysicspub/458
Autor:
James C. L. Chow, Grigor N. Grigorov
Publikováno v:
Medical physics. 39(7Part3)
This study evaluated the dosimetric impact of bone heterogeneity on the surface dose and dose prescription, when dose is assumed to be prescribed on a homogeneous medium in kV x-ray radiotherapy. A heterogeneous phantom containing a thin water layer
Autor:
Grigor N. Grigorov, James C. L. Chow
Publikováno v:
Medical Dosimetry. 35:92-100
This study investigated dosimetric changes in a water phantom when a small air cavity was presented at the central axis of a clinical electron beam. We used 6-, 9-, and 16-MeV electron beams with a 10 x 10 cm(2) applicator and cutout produced by a Va
Autor:
Grigor N. Grigorov, James C. L. Chow
Publikováno v:
Journal of Applied Clinical Medical Physics
This study investigates the dosimetric dependence of the dimension of a lead (Pb) layer for shielding using clinical electron beams with different energies. Monte Carlo simulations were used to generate phase space files of the 4, 9 and 16 MeV electr
Publikováno v:
Journal of Radiotherapy in Practice. 7:133-140
Dosimetric changes caused by the positional uncertainty of centring a small electron cutout to the machine central beam axis (CAX) of the linear accelerator (linac) were investigated. First, six circular cutouts with 4 cm diameter were made with thei
Autor:
Grigor N. Grigorov, James C. L. Chow
Publikováno v:
Medical Physics. 35:1241-1250
In electron radiotherapy of superficial lesions in the eyelid, lip, buccal mucosa, ear, and nose, backscattered electrons are produced from the lead shield used to protect the critical tissue underneath the tumor. In this study, the backscattered ele
Autor:
James C. L. Chow, Grigor N. Grigorov
Publikováno v:
Medical Physics. 35:70-76
The effect of beam obliquity on the surface relative dose profiles for the tangential photon beams was studied. The 6 and 15 MV photon beams with 4×4 and 10×10 cm2 field sizes produced by a Varian 21 EX linear accelerator were used. Phase-space mod
Publikováno v:
Medical Dosimetry. 31:249-258
The surface doses of 6- and 15-MV prostate intensity-modulated radiation therapy (IMRT) irradiations were measured and compared to those from a 15-MV prostate 4-beam box (FBB). IMRT plans (step-and-shoot technique) using 5, 7, and 9 beams with 6- and
Publikováno v:
Medical Physics. 33:4606-4613
Using a Varian 21 EX linear accelerator with a multileaf collimator (MLC) of 120 leaves, the penumbra regions of beam profiles within an irregular multileaf collimated fields were studied. MLC fields with different leaf stepping angles from 21.8 deg.
Autor:
Slav Yartsev, Grigor N. Grigorov, Tomas Kron, Michael Lock, George Rodrigues, Eugene Wong, David D'Souza, Glenn Bauman, Jeff Chen
Publikováno v:
Radiotherapy and Oncology. 80:374-377
The purpose of this study was to assess a variety of potential IMRT class solutions as compared to a helical tomotherapy (HT) class solution for localized prostate cancer. Target and critical structures were contoured on 10 prostate cancer patient CT