Neutron and gamma spectroscopy for clinical dosimetry.

abstract：:A technique was developed to reduce the size and magnitude of the hot and cold spots in the abutting regions of photon and electron fields. The photon and electron fields were set up such that the photon field extended approximately 2 cm into the electron field in the abutting region. The region of the photon beam tha...

journal_title：Medical physics

authors： Li JG,Xing L,Boyer AL,Hamilton RJ,Spelbring DR,Turian JV

更新日期：1999-11-01 00:00:00

abstract：PURPOSE:The aim of this work is to search for new metrics that could give more reliable acceptance/rejection criteria on the IMRT verification process and to offer solutions to the discrepancies found among different conventional metrics. Therefore, besides conventional metrics, new ones are proposed and evaluated with...

journal_title：Medical physics

authors： Garcia-Romero A,Hernandez-Vitoria A,Millan-Cebrian E,Alba-Escorihuela V,Serrano-Zabaleta S,Ortega-Pardina P

更新日期：2016-11-01 00:00:00

abstract：PURPOSE:To report on significant dose enhancement effects caused by magnetic fields aligned parallel to 6 MV photon beam radiotherapy of small lung tumors. Findings are applicable to future inline MRI-guided radiotherapy systems. METHODS:A total of eight clinical lung tumor cases were recalculated using Monte Carlo me...

journal_title：Medical physics

authors： Oborn BM,Ge Y,Hardcastle N,Metcalfe PE,Keall PJ

更新日期：2016-01-01 00:00:00

abstract：PURPOSE:To experimentally commission a dual-energy CT (DECT) joint statistical image reconstruction (JSIR) method, which is built on a linear basis vector model (BVM) of material characterization, for proton stopping power ratio (SPR) estimation. METHODS:The JSIR-BVM method builds on the relationship between the energ...

journal_title：Medical physics

authors： Zhang S,Han D,Williamson JF,Zhao T,Politte DG,Whiting BR,O'Sullivan JA

更新日期：2019-01-01 00:00:00

abstract：:Numerical reconstruction of x-ray spectra from narrow-beam transmission data was tested with published spectra in the range from 45 to 100 kVp. Transmission curves were calculated from the spectra to simulate measured data. Spectra were reconstructed from these transmission curves with use of an iterative numerical an...

journal_title：Medical physics

authors： Huang PH,Chen TS,Kase KR

更新日期：1986-09-01 00:00:00

abstract：PURPOSE:Tissue textures have been recognized as biomarkers for various clinical tasks. In computed tomography (CT) image reconstruction, it is important but challenging to preserve the texture when lowering x-ray exposure from full- toward low-/ultra-low dose level. Therefore, this paper aims to explore the texture-dos...

journal_title：Medical physics

authors： Gao Y,Liang Z,Xing Y,Zhang H,Pomeroy M,Lu S,Ma J,Lu H,Moore W

更新日期：2020-10-01 00:00:00

abstract：:A simple modification is presented for two commercially available hyperthermia applicators which dramatically improves the regulation and dynamic control of the temperature at the bolus/tissue interface. This alteration requires the addition of a variable speed pump, bubble trap, simple heat exchanger, and a few minor...

journal_title：Medical physics

authors： Diederich CJ,Stauffer PR,Bozzo D

更新日期：1994-09-01 00:00:00

abstract：:The intensity modulated arc has been proposed as an alternative to tomotherapy. Treatment planing systems more typically model the conventional step and shoot or sliding window dynamic multileaf collimator (DMLC) deliveries, and may not support intensity modulated arc therapy (IMAT). As well, another potential drawbac...

journal_title：Medical physics

authors： MacKenzie MA,Robinson DM

更新日期：2002-10-01 00:00:00

abstract：:Cone beam transmission CT (CB-CT) improves SPECT imaging by providing high-quality attenuation maps for attenuation compensation and for correlated SPECT and CT imaging. The present work measures the detection nonuniformity for CB-CT implemented with a gamma camera, and applies nonuniformity corrections to make CB-CT ...

journal_title：Medical physics

authors： Manglos SH,Capone RB,Bassano DA

更新日期：1992-03-01 00:00:00

abstract：:The purpose of this paper is to examine the thermal dose distribution, to configure the optimal absorbed power deposition, and to design an appropriate heating strategy for ultrasound thermal therapy. This work employs simulation programs, which are based on the transient bio-heat transfer equation and an ideal absorb...

journal_title：Medical physics

authors： Lin WL,Liang TC,Yen JY,Liu HL,Chen YY

更新日期：2001-10-01 00:00:00

abstract：:Single photon emission computed tomography (SPECT) is an important technology for molecular imaging studies of small animals. In this arena, there is an increasing demand for high performance imaging systems that offer improved spatial resolution and detection efficiency. We have designed a multipinhole small animal i...

journal_title：Medical physics

authors： Funk T,Després P,Barber WC,Shah KS,Hasegawa BH

更新日期：2006-05-01 00:00:00

abstract：PURPOSE:Dual source CT (DSCT) systems utilize two measurement systems (A) and (B) offset by about 90 degrees. A special challenge in DSCT is cross-scattered radiation, i.e., scattered radiation from x-ray tube (B) detected in detector (A) and vice versa. Cross-scattered radiation can produce artifacts and degrade the c...

journal_title：Medical physics

authors： Petersilka M,Stierstorfer K,Bruder H,Flohr T

更新日期：2010-11-01 00:00:00

abstract：:The dosimetry of 192Ir linear sources with a commercial treatment planning computer system has been evaluated. Reference dose rate data were selected from the literature and normalized in a manner consistent with our clinical and dosimetric terminology. The results of the computer calculations are compared to the refe...

journal_title：Medical physics

authors： Kline RW,Gillin MT,Grimm DF,Niroomand-Rad A

更新日期：1985-09-01 00:00:00

abstract：PURPOSE:This paper presents the application of MAGIC-f gel in a three-dimensional dose distribution measurement and its ability to accurately measure the dose distribution from a tomotherapy unit. METHODS:A prostate intensity-modulated radiation therapy (IMRT) irradiation was simulated in the gel phantom and the treat...

journal_title：Medical physics

authors： Pavoni JF,Pike TL,Snow J,DeWerd L,Baffa O

更新日期：2012-05-01 00:00:00

abstract：PURPOSE:Liver segmentation is an important prerequisite for the assessment of liver cancer treatment options like tumor resection, image-guided radiation therapy (IGRT), radiofrequency ablation, etc. The purpose of this work was to evaluate a new approach for liver segmentation. METHODS:A graph cuts segmentation metho...

journal_title：Medical physics

authors： Beichel R,Bornik A,Bauer C,Sorantin E

更新日期：2012-03-01 00:00:00

abstract：PURPOSE:Brachytherapy is a treatment modality which delivers large doses of radiation in a reduced number of visits. Since a small number of large dose-per-fraction is administered in high dose rate brachytherapy, ensuring the right dose is delivered is highly critical. In this work, a scintillation detector is coupled...

journal_title：Medical physics

authors： Tho D,Beaulieu L

更新日期：2019-05-01 00:00:00

abstract：PURPOSE:Dual-energy computed tomography and dual-energy cone-beam computed tomography (DE-CBCT) are promising modalities for applications ranging from vascular to breast, renal, hepatic, and musculoskeletal imaging. Accordingly, the optimization of imaging techniques for such applications would benefit significantly fr...

journal_title：Medical physics

authors： Gang GJ,Zbijewski W,Webster Stayman J,Siewerdsen JH

更新日期：2012-08-01 00:00:00

abstract：PURPOSE:This study (1) examines a variety of real-world cases where systematic errors were not detected by widely accepted methods for IMRT/VMAT dosimetric accuracy evaluation, and (2) drills-down to identify failure modes and their corresponding means for detection, diagnosis, and mitigation. The primary goal of detai...

journal_title：Medical physics

authors： Nelms BE,Chan MF,Jarry G,Lemire M,Lowden J,Hampton C,Feygelman V

更新日期：2013-11-01 00:00:00

abstract：PURPOSE:The response of human cells to applied electrical signals depends on the cellular health status, because it is influenced by the composition and structure of the main cellular components. Therefore, electrical impedance-based techniques can be considered as sensitive tools to investigate healthy or disease stat...

journal_title：Medical physics

authors： Ambrico M,Lasalvia M,Ligonzo T,Ambrico PF,Perna G,Capozzi V

更新日期：2020-10-01 00:00:00

abstract：:For an effective radiotherapy the exact tumor location must be determined. The localization has to take into account patient's setup position as well as internal organ motion. Among the different localization methods, the use of a computer tomography (CT) scanner in the therapy room has been proposed recently. Achievi...

journal_title：Medical physics

authors： Vences L,Wulf J,Vordermark D,Sauer O,Berlinger K,Roth M

更新日期：2005-11-01 00:00:00

abstract：PURPOSE:Given its sensitivity to anatomical variations, proton therapy is expected to benefit greatly from integration with magnetic resonance imaging for online anatomy monitoring during irradiation. Such an integration raises several challenges, as both systems mutually interact. The proton beam will experience quasi...

journal_title：Medical physics

authors： Schellhammer SM,Gantz S,Lühr A,Oborn BM,Bussmann M,Hoffmann AL

更新日期：2018-07-01 00:00:00

abstract：PURPOSE:Statistical modeling of an ultrasound backscattered echo envelope is used for tissue characterization. However, in the presence of complex structures within the analyzed area, estimation of parameters is disturbed and unreliable, e.g., in the case of breast tumor classification. In order to improve the differen...

journal_title：Medical physics

authors： Byra M,Nowicki A,Wróblewska-Piotrzkowska H,Dobruch-Sobczak K

更新日期：2016-10-01 00:00:00

abstract：PURPOSE:To automatically and efficiently segment the lesion area of the colonoscopy polyp image, a polyp segmentation method has been presented. METHODS:An ensemble model of pretrained convolutional neural networks was proposed, using Unet-VGG, SegNet-VGG, and PSPNet. Firstly, the Unet-VGG is obtained by the first 10 ...

journal_title：Medical physics

authors： Guo X,Zhang N,Guo J,Zhang H,Hao Y,Hang J

更新日期：2019-12-01 00:00:00

abstract：:A new energy selective detector for dual energy computed radiography has been developed that combines many of the advantages of x-ray tube voltage switching and single exposure double screen detectors. The new active detector utilizes electro-optical modulation of the response of the storage phosphor screens to allow ...

journal_title：Medical physics

authors： Alvarez RE

更新日期：1996-10-01 00:00:00

abstract：:Photoelectric-enhanced radiation therapy is a bimodal therapy, consisting of the administration of highly radiation-absorbing substances into the tumor area and localized regional irradiation with orthovoltage x-rays. Irradiation can be performed by a modified computed tomography (CT) unit equipped with an additional ...

journal_title：Medical physics

authors： Jost G,Mensing T,Golfier S,Lawaczeck R,Pietsch H,Hütter J,Cibik L,Gerlach M,Krumrey M,Fratzscher D,Arkadiev V,Wedell R,Haschke M,Langhoff N,Wust P,Lüdemann L

更新日期：2009-06-01 00:00:00

abstract：PURPOSE:Computational models are widely used during the design and characterization of microwave ablation (MWA) devices, and have been proposed for pretreatment planning. Our objective was to assess three-dimensional (3D) transient temperature and ablation profiles predicted by MWA computational models with temperature...

journal_title：Medical physics

authors： Faridi P,Keselman P,Fallahi H,Prakash P

更新日期：2020-09-01 00:00:00

abstract：:The accuracy of interpolation or averaging procedures for obtaining the calibration coefficient N(K) for 192Ir high-dose-rate brachytherapy sources has been investigated using the EGSnrc Monte Carlo simulation system. It is shown that the widely used two-point averaging procedure of Goetsch et al. [Med. Phys. 18, 462 ...

journal_title：Medical physics

authors： Mainegra-Hing E,Rogers DW

更新日期：2006-09-01 00:00:00

abstract：:Ultrasound-induced blood stasis has been observed for more than 30 years. Most of the literature has been focused on the health risks associated with this phenomenon and methods employed to prevent stasis from occurring during ultrasound imaging. To date, experimental observations have been either in vitro or invasive...

journal_title：Medical physics

authors： Winey BA,Misic V,Liao L,Parker K,Fenton BM,Yu Y

更新日期：2006-06-01 00:00:00

abstract：:New x-ray radiographic systems based on large-area flat-panel technology have revolutionized our capability to produce digital x-ray images. However, these imagers are extraordinarily expensive compared to the systems they are replacing. Hence, there is a need for a low-cost digital imaging system for general applicat...

journal_title：Medical physics

authors： Webster CA,Koprinarov I,Germann S,Rowlands JA

更新日期：2008-03-01 00:00:00

abstract：PURPOSE:To present EBT2 film verification of treatment planning with the eXtend System, a relocatable frame system for multiple-fraction or serial multiple-session radiosurgery. METHODS:A human head shaped phantom simulated the verification process for fractionated Gamma Knife (GK) treatment. Phantom preparation for e...

journal_title：Medical physics

authors： Gopishankar N,Bisht RK

更新日期：2012-06-01 00:00:00