General strategy for the protection of organs at risk in IMRT therapy of a moving body.

abstract：PURPOSE:Pulmonary magnetic-resonance-imaging (MRI) and x-ray computed-tomography have provided strong evidence of spatially and temporally persistent lung structure-function abnormalities in asthmatics. This has generated a shift in their understanding of lung disease and supports the use of imaging biomarkers as inter...

journal_title：Medical physics

authors： Guo F,Svenningsen S,Eddy RL,Capaldi DPI,Sheikh K,Fenster A,Parraga G

更新日期：2016-06-01 00:00:00

abstract：:Permanent implantation of 125I (iodine) or 103Pd (palladium) sources is a popular treatment option in the management of early stage prostate cancer. New sources are being developed, some of which are being marketed for different clinical applications. A new technique of adjuvant stereotactic permanent seed breast impl...

journal_title：Medical physics

authors： Abboud F,Scalliet P,Vynckier S

更新日期：2008-12-01 00:00:00

abstract：PURPOSE:The number of pencil beam scanned proton therapy (PBS-PT) facilities equipped with cone-beam computed tomography (CBCT) imaging treating thoracic indications is constantly rising. To enable daily internal motion monitoring during PBS-PT treatments of thoracic tumors, we assess the performance of Motion-Aware Re...

journal_title：Medical physics

authors： den Otter LA,Chen K,Janssens G,Meijers A,Both S,Langendijk JA,Rosen LR,Wu HT,Knopf AC

更新日期：2020-12-01 00:00:00

abstract：PURPOSE:To investigate the feasibility of implementing a novel approach for patient-specific QA of TomoDirect(TM) whole breast treatment. METHODS:The most currently used TomoTherapy DQA method, consisting in the verification of the 2D dose distribution in a coronal or sagittal plane of the Cheese Phantom by means of g...

journal_title：Medical physics

authors： Catuzzo P,Zenone F,Aimonetto S,Peruzzo A,Casanova Borca V,Pasquino M,Franco P,La Porta MR,Ricardi U,Tofani S

更新日期：2012-07-01 00:00:00

abstract：PURPOSE:To use machine-learning algorithms and blur measure (BM) operators to automatically detect motion blur in mammograms. Motion blur has been reported to reduce lesion detection performance and mask small abnormalities, resulting in failure to detect them until they reach more advanced stages. Automatic detection ...

journal_title：Medical physics

authors： Kamona N,Loew M

更新日期：2020-04-01 00:00:00

abstract：:Image intensifier-television-video digitizer (IITVD) systems are commonly used for digital planar image acquisition in radiology. However, the well-known distortions inherent in these systems limit their utility in research and in some clinical applications where quantitatively correct images are required. Software co...

journal_title：Medical physics

authors： Boone JM,Seibert JA,Barrett WA,Blood EA

更新日期：1991-03-01 00:00:00

abstract：PURPOSE:In prostate radiotherapy, dose distribution may be calculated on CT images, while the MRI can be used to enhance soft tissue visualization. Therefore, a registration between MR and CT images could improve the overall treatment planning process, by improving visualization with a demonstrated interobserver deline...

journal_title：Medical physics

authors： Hamdan I,Bert J,Rest CCL,Tasu JP,Boussion N,Valeri A,Dardenne G,Visvikis D

更新日期：2017-12-01 00:00:00

abstract：:Amorphous selenium (a-Se) based real-time flat-panel imagers (FPIs) are finding their way into the digital radiology department because they offer the practical advantages of digital x-ray imaging combined with an image quality that equals or outperforms that of conventional systems. The temporal imaging characteristi...

journal_title：Medical physics

authors： Rau AW,Bakueva L,Rowlands JA

更新日期：2005-10-01 00:00:00

abstract：:In x-ray spectral measurement using a semiconductor detector system, accurate positioning of the detector in front of the anode is very important. This needs accurate determination of the focal spot position on the target in an x-ray tube. We present a simple technique to determine the focal spot position accurately. ...

journal_title：Medical physics

authors： Kubota H,Ozaki Y,Matsumoto M,Kanamori H

更新日期：1993-07-01 00:00:00

abstract：PURPOSE:The purpose of this work was to investigate the use of an experimental complementary metal-oxide-semiconductor (CMOS) active pixel sensor (APS) for tracking of moving fiducial markers during radiotherapy. METHODS:The APS has an active area of 5.4 × 5.4 cm and maximum full frame read-out rate of 20 frame s(-1),...

journal_title：Medical physics

authors： Osmond JP,Zin HM,Harris EJ,Lupica G,Allinson NM,Evans PM

更新日期：2011-11-01 00:00:00

abstract：:Transthoracic electrical impedance Z consists of a constant baseline component Z0 and the time variable component delta Z such that Z = Z0 + delta Z. The first time derivative of Z has a negative peak, the magnitude of which is (dZ/dt)min. Measurements of 170 volunteers show that (dZ/dt)min is a function of the consta...

journal_title：Medical physics

authors： Djordjevich L,Sadove MS

更新日期：1981-01-01 00:00:00

abstract：PURPOSE:To compare beam characteristics of superficial X-rays with 6 MeV Electrons for the purpose of replacing superficial treatments with electron fields for skin lesions. METHODS:Electron beam cutouts were made with 12mm thickness cerrobend in diameters 2-5 cm to match superficial X-ray machine cones. Central axis ...

journal_title：Medical physics

authors： Avadhani J,Sasidharan S,Carton C,Lowen M,Klapproth T,Licitra C

更新日期：2012-06-01 00:00:00

abstract：:Boron neutron capture therapy (BNCT) is an experimental type of radiotherapy, presently being used to treat glioblastoma and melanoma. To improve patient safety and to determine the radiobiological characteristics of the epithermal neutron beam of Finnish BNCT facility (FiR 1) dose-response studies were carried on the...

journal_title：Medical physics

authors： Seppälä T,Auterinen I,Aschan C,Serén T,Benczik J,Snellman M,Huiskamp R,Ramadan UA,Kankaanranta L,Joensuu H,Savolainen S

更新日期：2002-11-01 00:00:00

abstract：PURPOSE:The standardized uptake value (SUV) is a quantitative measure of FDG tumor uptake frequently used as a tool to monitor therapeutic response. This study aims to (i) assess the reproducibility and uncertainty of SUV max and SUV mean, due to purely statistical, i.e., nonbiological, effects and (ii) to establish th...

journal_title：Medical physics

authors： Schwartz J,Humm JL,Gonen M,Kalaigian H,Schoder H,Larson SM,Nehmeh SA

更新日期：2011-05-01 00:00:00

abstract：:A detailed Monte Carlo study of the PTW-diamond solid state detector response in megavoltage photon beams (60Co gamma rays to 25 MV x rays) has been performed with the EGS4 Monte Carlo Code. The sensitive volume of the diamond detector is a disk of diameter 4.4 mm and thickness 0.40 mm. The phantom material was water ...

journal_title：Medical physics

authors： Mobit PN,Sandison GA

更新日期：1999-11-01 00:00:00

abstract：PURPOSE:The authors have developed a quantitative calibration method for a multileaf collimator (MLC) which measures individual leaf positions relative to the MLC backup jaw on an Elekta Synergy linear accelerator. METHODS:The method utilizes a commercially available two-axis detector array (Profiler 2; Sun Nuclear Co...

journal_title：Medical physics

authors： Simon TA,Kahler D,Simon WE,Fox C,Li J,Palta J,Liu C

更新日期：2009-10-01 00:00:00

abstract：PURPOSE:The cardiovascular system (CVS) regulation can be studied from a central viewpoint, through heart rate variability (HRV) data, and from a peripheral viewpoint, through laser Doppler flowmetry (LDF) signals. Both the central and peripheral CVSs are regulated by several interacting mechanisms, each having its own...

journal_title：Medical physics

authors： Humeau A,Buard B,Mahé G,Rousseau D,Chapeau-Blondeau F,Abraham P

更新日期：2010-12-01 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：:Most detectors in current positron emission tomography (PET) scanners and prototypes use lutetium oxyorthosilicate (LSO) or lutetium yttrium oxyorthosilicate (LYSO) scintillators. The aim of this work is to provide a complete set of background energy spectra, due to the scintillator intrinsic radioactivity, for a wide...

journal_title：Medical physics

authors： Domínguez-Jiménez DY,Alva-Sánchez H

更新日期：2021-01-21 00:00:00

abstract：PURPOSE:Since the introduction of clinical x-ray phase-contrast mammography (PCM), a technique that exploits refractive-index variations to create edge enhancement at tissue boundaries, a number of optimization studies employing physical image-quality metrics have been performed. Ideally, task-based assessment of PCM w...

journal_title：Medical physics

authors： Zysk AM,Brankov JG,Wernick MN,Anastasio MA

更新日期：2012-02-01 00:00:00

abstract：PURPOSE:There is significant current interest in the use of biological image guidance in radiotherapy planning. In lung-cancer treatment, tumor motion due to respiration is known to be a limitation. This is particularly true in PET, where image data are collected over a number of minutes. An in-house-developed 4D PET a...

journal_title：Medical physics

authors： Perrin R,Evans PM,Webb S,Partridge M

更新日期：2010-02-01 00:00:00

abstract：:Significant advances have been made in recent years to improve photon dose calculation. However, accurate prediction of dose perturbation effects near the interfaces of different media, where charged particle equilibrium is not established, remain unsolved. Furthermore, changes in atomic number, which affect the multi...

journal_title：Medical physics

authors： Yu CX,Mackie TR,Wong JW

更新日期：1995-07-01 00:00:00

abstract：:Noise power spectrum (NPS) and detective quantum efficiency (DQE) for metal-plate/film portal detectors are reported for the Co-60 and Linac 10 MV spectra. The detectors consist of a double-emulsion portal film secured between plates of aluminum, copper, brass, or lead. The NPS was found to be independent of the detec...

journal_title：Medical physics

authors： Falco T,Fallone BG

更新日期：1998-12-01 00:00:00

abstract：PURPOSE:Radioembolization with yttrium-90 microspheres may be optimized with patient-specific pretherapy treatment planning. Dose verification and validation of treatment planning methods require quantitative imaging of the post-therapy distribution of yttrium-90 (Y-90). Methods for quantitative imaging of Y-90 using b...

journal_title：Medical physics

authors： Yue J,Mauxion T,Reyes DK,Lodge MA,Hobbs RF,Rong X,Dong Y,Herman JM,Wahl RL,Geschwind JH,Frey EC

更新日期：2016-10-01 00:00:00

abstract：:A quality assurance protocol has been developed to assess the relative accuracy of computerized monitor unit calculations. Results from this testing reveal that errors (defined as the difference between the computer results and those obtained using a standard formula with manual calculation) in monitor unit calculator...

journal_title：Medical physics

authors： Dahl RA,McCullough EC,Mellenberg DE

更新日期：1990-01-01 00:00:00

abstract：PURPOSE:To perform radiomic analysis of primary tumors extracted from pretreatment contrast-enhanced computed tomography (CE-CT) images for patients with oropharyngeal cancers to identify discriminant features and construct an optimal classifier for the characterization and prediction of human papilloma virus (HPV) sta...

journal_title：Medical physics

authors： Bagher-Ebadian H,Lu M,Siddiqui F,Ghanem AI,Wen N,Wu Q,Liu C,Movsas B,Chetty IJ

更新日期：2020-02-01 00:00:00

abstract：PURPOSE:To develop a pharmacokinetic modelfree framework to analyze the dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) data for assessment of response of brain metastases to radiation therapy. METHODS:Twenty patients with 45 analyzable brain metastases had MRI scans prior to whole brain radiation thera...

journal_title：Medical physics

authors： Farjam R,Tsien CI,Lawrence TS,Cao Y

更新日期：2014-01-01 00:00:00

abstract：PURPOSE:Recent guidance by The Joint Commission and CRCPD recommendations require establishing CT reference dose levels (RDLs) for clinical protocols and recording CT dose metrics in the patient's medical record. This presentation addresses which dose values in the CT report should be recorded for the purposes of monit...

journal_title：Medical physics

authors： Guild J,Arbique G,Blackburn T,Gallet J,Anderson J

更新日期：2012-06-01 00:00:00

abstract：:The purpose of the present study is to characterize electron contamination in photon beams in different clinical situations. Variations with field size, beam modifier (tray, shaping block) and source-surface distance (SSD) were studied. Percentage depth dose measurements with and without a purging magnet and replacing...

journal_title：Medical physics

authors： Lopez Medina A,Teijeiro A,Garcia J,Esperon J,Terron JA,Ruiz DP,Carrion MC

更新日期：2005-05-01 00:00:00

abstract：PURPOSE:Intraventricular hemorrhage (IVH) is a major cause of brain injury in preterm neonates. Three dimensional ultrasound (US) imaging systems have been developed to visualize 3D anatomical structure of preterm neonatal intracranial ventricular system with IVH and ventricular dilation. To allow quantitative analysis...

journal_title：Medical physics

authors： Chen Y,Qiu W,Kishimoto J,Gao Y,Chan RH,de Ribaupierre S,Fenster A,Chiu B

更新日期：2015-11-01 00:00:00