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:Onboard imaging-currently performed primarily by x-ray transmission modalities-is essential in modern radiation therapy. As radiation therapy moves toward personalized medicine, molecular imaging, which views individual gene expression, may also be important onboard. Nuclear medicine methods, such as single pho...

journal_title：Medical physics

authors： Bowsher J,Yan S,Roper J,Giles W,Yin FF

更新日期：2014-01-01 00:00:00

abstract：PURPOSE:Transcranial focused ultrasound is an emerging therapeutic modality that can be used to perform noninvasive neurosurgical procedures. The current clinical transcranial phased array operates at 650 kHz, however the development of a higher frequency array would enable more precision, while reducing the risk of st...

journal_title：Medical physics

authors： Pajek D,Hynynen K

更新日期：2013-12-01 00:00:00

abstract：PURPOSE:Air-communicating well ionization chambers are commonly used to assess air kerma strength of sources used in brachytherapy. The signal produced is supposed to be proportional to the air density within the chamber and, therefore, a density-independent air kerma strength is obtained when the measurement is correc...

journal_title：Medical physics

authors： Tornero-López AM,Guirado D,Perez-Calatayud J,Ruiz-Arrebola S,Simancas F,Gazdic-Santic M,Lallena AM

更新日期：2013-12-01 00:00:00

abstract：PURPOSE:Fluence field modulated computed tomography (FFMCT) presents a novel approach for acquiring CT images, whereby a patient model guides dynamically changing fluence patterns in an attempt to achieve task-based, user-prescribed, regional variations in image quality, while also controlling dose to the patient. This...

journal_title：Medical physics

authors： Bartolac S,Jaffray D

更新日期：2013-12-01 00:00:00

abstract：PURPOSE:To use Cone Beam CT scans obtained just prior to treatments of head and neck cancer patients to measure the setup error and cumulative dose uncertainty of the cochlea. METHODS:Data from 10 head and neck patients with 10 planning CTs and 52 Cone Beam CTs taken at time of treatment were used in this study. Patie...

journal_title：Medical physics

authors： Yan M,Lovelock D,Hunt M,Mechalakos J,Hu Y,Pham H,Jackson A

更新日期：2013-12-01 00:00:00

abstract：PURPOSE:Stray neutron radiation is of concern after radiation therapy, especially in children, because of the high risk it might carry for secondary cancers. Several previous studies predicted the stray neutron exposure from proton therapy, mostly using Monte Carlo simulations. Promising attempts to develop analytical ...

journal_title：Medical physics

authors： Pérez-Andújar A,Zhang R,Newhauser W

更新日期：2013-12-01 00:00:00

abstract：PURPOSE:To build a statistical model to quantitatively correlate the anatomic features of structures and the corresponding dose-volume histogram (DVH) of head and neck (HN) Tomotherapy (Tomo) plans. To study if the model built upon one intensity modulated radiation therapy (IMRT) technique (such as conventional Linac) ...

journal_title：Medical physics

authors： Lian J,Yuan L,Ge Y,Chera BS,Yoo DP,Chang S,Yin F,Wu QJ

更新日期：2013-12-01 00:00:00

abstract：PURPOSE:Two-dimensional ultrasound (2D US) imaging is commonly used for diagnostic and intraoperative guidance of interventional liver procedures; however, 2D US lacks volumetric information that may benefit interventional procedures. Over the past decade, three-dimensional ultrasound (3D US) has been developed to prov...

journal_title：Medical physics

authors： Neshat H,Cool DW,Barker K,Gardi L,Kakani N,Fenster A

更新日期：2013-11-01 00:00:00

abstract：PURPOSE:Over the last ten years, there has been an extensive growth in the development of microSPECT imagers. Most of the systems are based on the combination of conventional, relatively large gamma cameras with poor intrinsic spatial resolution and multipinhole collimators working in large magnification mode. Spatial ...

journal_title：Medical physics

authors： Van Holen R,Vandeghinste B,Deprez K,Vandenberghe S

更新日期：2013-11-01 00:00:00

abstract：PURPOSE:An improved method of image guidance for lung tumor biopsies could help reduce the high rate of false negatives. The aim of this work is to optimize the geometry of the scanning-beam digital tomography system (SBDX) for providing real-time 3D tomographic reconstructions for target verification. The unique geome...

journal_title：Medical physics

authors： Nelson G,Yoon S,Krishna G,Wilfley B,Fahrig R

更新日期：2013-11-01 00:00:00

abstract：PURPOSE:The purpose of this study is to adapt an equivalent source model originally developed for conventional CT Monte Carlo dose quantification to the radiation oncology context and validate its application for evaluating concomitant dose incurred by a kilovoltage (kV) cone-beam CT (CBCT) system integrated into a lin...

journal_title：Medical physics

authors： McMillan K,McNitt-Gray M,Ruan D

更新日期：2013-11-01 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 spatial and temporal tracking performance of a commercially available 3D optical surface imaging system is evaluated for its potential use in frameless stereotactic radiosurgery head tracking applications. METHODS:Both 3D surface and infrared (IR) marker tracking were performed simultaneously on a head pha...

journal_title：Medical physics

authors： Wiersma RD,Tomarken SL,Grelewicz Z,Belcher AH,Kang H

更新日期：2013-11-01 00:00:00

abstract：PURPOSE:High dose rate (HDR) brachytherapy is a radiation treatment technique capable of delivering large dose rates to the tumor. Radiation is delivered using remote afterloaders to drive highly active sources (commonly (192)Ir with an air KERMA strength range between 20,000 and 40,000 U, where 1 U = 1 μGy m(2)/h in a...

journal_title：Medical physics

authors： Espinoza A,Beeksma B,Petasecca M,Fuduli I,Porumb C,Cutajar D,Corde S,Jackson M,Lerch ML,Rosenfeld AB

更新日期：2013-11-01 00:00:00

abstract：PURPOSE:Pulse pileup occurring at high x-ray fluxes can severely degrade the energy resolution provided by a photon counting detector, which can represent a problem in spectroscopic CT when performing quantitative material discrimination tasks. As the effects of pileup can be most easily seen as a degradation of a dete...

journal_title：Medical physics

authors： Rink K,Oelfke U,Fiederle M,Zuber M,Koenig T

更新日期：2013-10-01 00:00:00

abstract：PURPOSE:To develop a real-time markerless 3D tumor tracking using kilovoltage (kV) cone-beam CT (CBCT) projection images during volumetric modulated arc therapy (VMAT) treatment of lung tumors. METHODS:The authors have developed a method to identify the position of lung tumors during VMAT treatment, where the current ...

journal_title：Medical physics

authors： Zhuang L,Liang J,Yan D,Zhang T,Marina O,Ionascu D

更新日期：2013-10-01 00:00:00

abstract：:Molecular imaging is the direct or indirect noninvasive monitoring and recording of the spatial and temporal distribution of in vivo molecular, genetic, and/or cellular processes for biochemical, biological, diagnostic, or therapeutic applications. Molecular images that indicate the presence of malignancy can be acqui...

journal_title：Medical physics

authors： Munley MT,Kagadis GC,McGee KP,Kirov AS,Jang S,Mutic S,Jeraj R,Xing L,Bourland JD

更新日期：2013-10-01 00:00:00

abstract：PURPOSE:Breast magnetic resonance imaging is highly sensitive but not very specific for the detection of breast cancer. Opportunities exist to supplement the image acquisition with a more specific modality provided the technical challenges of meeting space limitations inside the bore, restricted breast access, and elec...

journal_title：Medical physics

authors： Meaney PM,Golnabi AH,Epstein NR,Geimer SD,Fanning MW,Weaver JB,Paulsen KD

更新日期：2013-10-01 00:00:00

abstract：PURPOSE:This study aims to investigate carotid plaque calcification (CPC) using two-dimensional (2D) and 3D ultrashort echo time (UTE) magnetic resonance imaging (MRI) sequences and compare T1, T2*, water concentration, and bone mineral density (BMD) of CPC with those of cortical bone. METHODS:Twelve carotid plaque sp...

journal_title：Medical physics

authors： Du J,Peterson M,Kansal N,Bydder GM,Kahn A

更新日期：2013-10-01 00:00:00

abstract：PURPOSE:The authors introduce a novel method for defining standardized uptake values (SUVs) in PET∕CT based on routinely collected CT data. The goal of the study is to reduce, if possible, the variability of SUV in a heterogeneous population. Two well established methods for defining SUV are based on body weight (BW) a...

journal_title：Medical physics

authors： Hamill JJ,Sunderland JJ,LeBlanc AK,Kojima CJ,Wall J,Martin EB

更新日期：2013-09-01 00:00:00

abstract：PURPOSE:In this study, a dedicated device for ion chamber measurements of absorbed dose-to-water for a Nucletron microSelectron-v2 HDR (192)Ir brachytherapy source is presented. The device uses two ionization chambers in a so-called sandwich assembly. Using this setup and by taking the average reading of the two chambe...

journal_title：Medical physics

authors： Araki F,Kouno T,Ohno T,Kakei K,Yoshiyama F,Kawamura S

更新日期：2013-09-01 00:00:00

abstract：PURPOSE:4d cone-beam computed tomography (CBCT) scans are usually reconstructed by extracting the motion information from the 2d projections or an external surrogate signal, and binning the individual projections into multiple respiratory phases. In this "after-the-fact" binning approach, however, projections are uneve...

journal_title：Medical physics

authors： Fast MF,Wisotzky E,Oelfke U,Nill S

更新日期：2013-09-01 00:00:00

abstract：PURPOSE:To characterize the modulation transfer function (MTF) of proton/carbon radiography using Monte Carlo simulations. To assess the spatial resolution of proton/carbon radiographic imaging. METHODS:A phantom was specifically modeled with inserts composed of two materials with three different densities of bone and...

journal_title：Medical physics

authors： Seco J,Oumano M,Depauw N,Dias MF,Teixeira RP,Spadea MF

更新日期：2013-09-01 00:00:00

abstract：PURPOSE:In this study the Octavius detector 729 ionization chamber (IC) array with the Octavius 4D phantom was characterized for flattening filter (FF) and flattening filter free (FFF) static and rotational beams. The device was assessed for verification with FF and FFF RapidArc treatment plans. METHODS:The response o...

journal_title：Medical physics

authors： McGarry CK,O'Connell BF,Grattan MW,Agnew CE,Irvine DM,Hounsell AR

更新日期：2013-09-01 00:00:00

abstract：PURPOSE:Ultrasound-induced mild hyperthermia has advantages for noninvasive, localized and controlled drug delivery. In this study, a tissue-mimicking agarose-based phantom with a thermally sensitive indicator was developed for studying the spatial drug delivery profile using ultrasound-induced mild hyperthermia. METH...

journal_title：Medical physics

authors： Lai CY,Kruse D,Seo JW,Kheirolomoom A,Ferrara KW

更新日期：2013-08-01 00:00:00

abstract：PURPOSE:Commercially available fillable plastic inserts used in positron emission tomography phantoms usually have thick plastic walls, separating their content from the background activity. These "cold" walls can modify the intensity values of neighboring active regions due to the partial volume effect, resulting in e...

journal_title：Medical physics

authors： Berthon B,Marshall C,Edwards A,Evans M,Spezi E

更新日期：2013-08-01 00:00:00

abstract：PURPOSE:The purpose of this study was to evaluate the effect of various computed tomography (CT) thresholds on trapping volumetric measurements by multidetector CT in chronic obstructive pulmonary disease (COPD). METHODS:Twenty-three COPD patients were scanned with a 64-slice CT scanner in both the inspiratory and exp...

journal_title：Medical physics

authors： Wang X,Duan J,Du Y,Shen N,He B,Yuan H

更新日期：2013-08-01 00:00:00

abstract：PURPOSE:The measurement of malignant pleural mesothelioma is critical to the assessment of tumor response to therapy. Current response assessment standards utilize summed linear measurements acquired on three computed tomography (CT) sections. The purpose of this study was to evaluate manual area measurements as an alt...

journal_title：Medical physics

authors： Labby ZE,Straus C,Caligiuri P,MacMahon H,Li P,Funaki A,Kindler HL,Armato SG 3rd

更新日期：2013-08-01 00:00:00

abstract：PURPOSE:Credentialing can have an impact on whether or not a clinical trial produces useful quality data that is comparable between various institutions and scanners. With the recent increase of dynamic contrast enhanced-computed tomography (DCE-CT) usage as a companion biomarker in clinical trials, effective quality a...

journal_title：Medical physics

authors： Driscoll B,Keller H,Jaffray D,Coolens C

更新日期：2013-08-01 00:00:00

abstract：PURPOSE:Removal of the linear accelerator (linac) flattening filter enables a high rate of dose deposition with reduced treatment time. When used for megavoltage imaging, an unflat beam has reduced primary beam scatter resulting in sharper images. In fluoroscopic imaging mode, the unflat beam has higher photon count pe...

journal_title：Medical physics

authors： Christensen JD,Kirichenko A,Gayou O

更新日期：2013-08-01 00:00:00

abstract：PURPOSE:As hypoxic cells are more resistant to photon radiation, it is desirable to obtain information about the oxygen distribution in tumors prior to the radiation treatment. Noninvasive techniques are currently not able to provide reliable oxygenation maps with sufficient spatial resolution; therefore mathematical m...

journal_title：Medical physics

authors： Espinoza I,Peschke P,Karger CP

更新日期：2013-08-01 00:00:00

abstract：PURPOSE:The main objective of this work was to design a comprehensive dosimetry package that would keep all aspects of internal dose calculation within the framework of a single software environment and that would be applicable for a variety of dose calculation approaches. METHODS:Our MATLAB-based graphical user inter...

journal_title：Medical physics

authors： Grimes J,Uribe C,Celler A

更新日期：2013-07-01 00:00:00

abstract：PURPOSE:Scatter contamination in cone-beam computed tomography (CBCT) degrades the image quality by introducing shading artifacts. A moving-blocker-based approach has been proposed to simultaneously estimate scatter and reconstruct the complete volume within field of view (FOV) from a single CBCT scan. Promising result...

journal_title：Medical physics

authors： Ouyang L,Song K,Wang J

更新日期：2013-07-01 00:00:00

abstract：PURPOSE:To compare how the inclusion of the uncertainties in dose and optical density affects the results of the calibration of Gafchromic(®) EBT3 radiochromic films. METHODS:Five methods of least square minimization were compared for calibration of radiochromic films. These differed in the way in which the uncertaint...

journal_title：Medical physics

authors： Garcia LI,Azorin JF

更新日期：2013-07-01 00:00:00

abstract：PURPOSE:To compare optimization characteristics, plan quality, and treatment delivery efficiency between total marrow irradiation (TMI) plans using the new TomoTherapy graphic processing unit (GPU) based dose engine and CPU/cluster based dose engine. METHODS:Five TMI plans created on an anthropomorphic phantom were op...

journal_title：Medical physics

authors： Nalichowski A,Burmeister J

更新日期：2013-07-01 00:00:00

abstract：PURPOSE:A multi-institution dosimetry intercomparison has been undertaken of prostate intensity modulated radiation therapy (IMRT) delivery. The dosimetry intercomparison was incorporated into the quality assurance for site credentialing for the Trans-Tasman Radiation Oncology Group Prostate Fractionated Irradiation Tr...

journal_title：Medical physics

authors： Healy B,Frantzis J,Murry R,Martin J,Plank A,Middleton M,Catton C,Kron T

更新日期：2013-07-01 00:00:00

abstract：:In this paper, the authors review the field of resolution modeling in positron emission tomography (PET) image reconstruction, also referred to as point-spread-function modeling. The review includes theoretical analysis of the resolution modeling framework as well as an overview of various approaches in the literature...

journal_title：Medical physics

authors： Rahmim A,Qi J,Sossi V

更新日期：2013-06-01 00:00:00

abstract：PURPOSE:Prostate cancer ranks as one of the most common malignancies and currently represents the second leading cancer-specific cause of death in men. The current use of single modality transrectal ultrasound (TRUS) for biopsy guidance has a limited sensitivity and specificity for accurately identifying cancerous lesi...

journal_title：Medical physics

authors： Wan Y,Borsic A,Heaney J,Seigne J,Schned A,Baker M,Wason S,Hartov A,Halter R

更新日期：2013-06-01 00:00:00

abstract：PURPOSE:To investigate the effect of energy (kVp) and filters (no filter, half Bowtie, and full Bowtie) on the dose response curves of the Gafchromic XRQA2 film and nanoDot optical stimulated luminescence dosimeters (OSLDs) in CBCT dose fields. To measure surface and internal doses received during x-ray volume imager (...

journal_title：Medical physics

authors： Giaddui T,Cui Y,Galvin J,Yu Y,Xiao Y

更新日期：2013-06-01 00:00:00