Optimizing spectral CT parameters for material classification tasks.

abstract：:This study investigated the integration of the Calypso real-time tracking system, based on implanted ferromagnetic transponders and a detector array, into the current process for image-guided radiation treatment (IGRT) of prostate cancer at our institution. The current IGRT process includes magnetic resonance imaging ...

journal_title：Physics in medicine and biology

authors： Zhu X,Bourland JD,Yuan Y,Zhuang T,O'Daniel J,Thongphiew D,Wu QJ,Das SK,Yoo S,Yin FF

更新日期：2009-09-07 00:00:00

abstract：:Magnetic resonance imaging (MRI) may be used to image three-dimensional dose distributions of ionizing radiation in tissue equivalent gels infused with ferrous sulphate solutions, commonly known as Fricke gels. In this technique, ferrous (Fe2+) ions are oxidized to ferric (Fe3+) ions by free radicals produced by ioniz...

journal_title：Physics in medicine and biology

authors： Harris PJ,Piercy A,Baldock C

更新日期：1996-09-01 00:00:00

abstract：:We have developed and tested a GSO (gadolinium oxyorthosilicate) position-sensitive gamma detector which can be used with positron and single-photon radionuclides for imaging breast cancer or sentinel lymph node detection. Because GSO has a relatively good energy resolution for annihilation gammas as well as low energ...

journal_title：Physics in medicine and biology

authors： Yamamoto S,Matsumoto K,Senda M

更新日期：2006-01-21 00:00:00

abstract：:Online adaptive radiation therapy (ART) based on real-time magnetic resonance imaging represents a paradigm-changing treatment scheme. However, conventional quality assurance (QA) methods based on phantom measurements are not feasible with the patient on the treatment couch. The purpose of this work is to develop a fa...

journal_title：Physics in medicine and biology

authors： Wang Y,Mazur TR,Park JC,Yang D,Mutic S,Li HH

更新日期：2017-06-21 00:00:00

abstract：:Geometric and penetration responses of a multihole focusing collimator to a point source have been determined using a digital computer and a ray tracing technique. Results are presented as point and line spread functions for collimated rays and penetrating rays, and as plane sensitivities and modulation transfer funct...

journal_title：Physics in medicine and biology

authors： Jahns MJ

更新日期：1981-01-01 00:00:00

abstract：:The aim of this study was to measure entrance skin doses on patients undergoing cone-beam computed tomography (CBCT) examinations, to establish conversion factors between skin and organ doses, and to estimate cancer risk from CBCT exposures. 266 patients (age 8-83) were included, involving three imaging centres. CBCT ...

journal_title：Physics in medicine and biology

authors： Pauwels R,Cockmartin L,Ivanauskaité D,Urbonienė A,Gavala S,Donta C,Tsiklakis K,Jacobs R,Bosmans H,Bogaerts R,Horner K,SEDENTEXCT Project Consortium.

更新日期：2014-07-21 00:00:00

abstract：:Gas target systems have been used for decades on cyclotrons to produce radionuclides for medical imaging. However, the activity recovered from such targets is often lower than its theoretically predicted value. Past research has suggested that nuclide interactions with the walls of the target body may play a key role ...

journal_title：Physics in medicine and biology

authors： Zacchia NA,Buckley KR,Martinez GM,Ruth TJ,Martinez DM,Hoehr C

更新日期：2018-09-28 00:00:00

abstract：:The interest in positron emission tomography (PET) and particularly in hybrid integrated PET/CT systems has significantly increased in the last few years due to the improved quality of the obtained images. Nevertheless, one of the most important limits of the PET imaging technique is still its poor spatial resolution ...

journal_title：Physics in medicine and biology

authors： Rapisarda E,Bettinardi V,Thielemans K,Gilardi MC

更新日期：2010-07-21 00:00:00

abstract：:The purpose of this study was to validate the accuracy and reliability of volume measurements obtained using three-dimensional (3D) thoracoscopic ultrasound (US) imaging. Artificial "tumours" were created by injecting a liquid agar mixture into spherical moulds of known volume. Once solidified, the "tumours" were impl...

journal_title：Physics in medicine and biology

authors： Hornblower VD,Yu E,Fenster A,Battista JJ,Malthaner RA

更新日期：2007-01-07 00:00:00

abstract：:The rationale for multi-modality imaging is to integrate the strengths of different imaging technologies while reducing the shortcomings of an individual modality. The work presented here proposes a limited-field-of-view (LFOV) SPECT reconstruction technique that can be implemented on a multi-modality MR/SPECT system ...

journal_title：Physics in medicine and biology

authors： Lee KS,Roeck WW,Gullberg GT,Nalcioglu O

更新日期：2011-02-07 00:00:00

abstract：:The spatial resolution of 2D detector arrays equipped with ionization chambers or diodes, used for the dose verification of IMRT treatment plans, is limited by the size of the single detector and the centre-to-centre distance between the detectors. Optimization criteria with regard to these parameters have been develo...

journal_title：Physics in medicine and biology

authors： Poppe B,Djouguela A,Blechschmidt A,Willborn K,Rühmann A,Harder D

更新日期：2007-05-21 00:00:00

abstract：:To replace the conventional pinhole (normal cone-beam) collimator, a novel skew-slit collimator was previously proposed and a Novikov-type algorithm developed to reconstruct images using the skew-slit geometry. The goal of this paper is to develop a reconstruction algorithm that has better noise control than the Novik...

journal_title：Physics in medicine and biology

authors： Tang Q,Zeng GL,Huang Q

更新日期：2006-12-07 00:00:00

abstract：:Detailed studies of the basic contrast mechanisms in computerized transverse axial tomography scanners have been carried out. Contrast is related to the effective atomic numbers and electron densities of materials and the resultant linear attenuation coefficients. We have therefore quantitatively evaluated various sam...

journal_title：Physics in medicine and biology

authors： Tsai CM,Cho ZH

更新日期：1976-07-01 00:00:00

abstract：:Photon quality correction factors (kQy) for ionization chamber photon dosimetry in an epithermal neutron beam were determined according to a modified absorbed dose to water formalism which was extended to mixed radiation fields. We have studied two commercially available ionization chambers in the epithermal neutron b...

journal_title：Physics in medicine and biology

authors： Munck af Rosenschöld PM,Ceberg CP,Giusti V,Andreo P

更新日期：2002-07-21 00:00:00

abstract：:In positron emission tomography (PET) with pixelated detectors, a significant number of annihilation photons interact with scintillation crystals through single or multiple Compton scattering events. When these partial energy depositions occur across multiple crystal elements, we call them inter-crystal scatter (ICS) ...

journal_title：Physics in medicine and biology

authors： Park H,Lee JS

更新日期：2020-10-21 00:00:00

abstract：:Stopping power data for protons in tissue-equivalent gas (64.4% CH4 + 32.4% CO2 + 3.2% N2, partial pressures) were derived from experimentally determined ranges and from differential ionisation distributions using the differential energy required per ion pair formed to convert ionisation to energy loss. The proton ene...

journal_title：Physics in medicine and biology

authors： Waibel E,Willems G

更新日期：1987-03-01 00:00:00

abstract：:We have developed and tested an MR-compatible gamma probe to simultaneously obtain anatomical information and functional information during surgery. The probe consists of a probe head, an optical fibre bundle and a photo-multiplier tube (PMT). The NaI(T1) scintillator contained in the probe head is connected to a 7 m ...

journal_title：Physics in medicine and biology

authors： Yamamoto S,Kuroda K,Senda M

更新日期：2004-08-07 00:00:00

abstract：:In order (i) to evaluate the dose uncertainty of the mouthpiece in daily use during intensity-modulated radiotherapy of patients with head and neck cancer, and (ii) to present a system for in vivo dosimetry of the oral mucosa, we equipped the mouthpiece with alanine dosimeter probes for in vivo dosimetry. The aim was ...

journal_title：Physics in medicine and biology

authors： Wagner D,Anton M,Vorwerk H

更新日期：2011-03-07 00:00:00

abstract：:This work studies the effect of age on lung dose commitments arising from the inhalation of an atmosphere containing radionuclides of varying half-lives and physical sizes. This dependence is significant in many cases, approaching a ratio of 2 in several instances when the maximum dose at a given age is compared with ...

journal_title：Physics in medicine and biology

authors： Crawford DJ

更新日期：1982-04-01 00:00:00

abstract：:Fast calculation or simulation of the ablation zone induced by radiofrequency ablation (RFA) has a critical role in hepatic RFA planning and therapy. However, it remains challenging to approximate the ablation zone in real time, especially when more than one probe is involved in one ablation session. This paper presen...

journal_title：Physics in medicine and biology

authors： Chen R,Zhang J,Kong D,Lou Q,Lu F

更新日期：2021-01-27 00:00:00

abstract：:Radionuclides which decay by electron capture accompanied by Auger electron cascades, or by beta emission are thought to be excessively damaging when incorporated into the molecular structure of mammalian cell nuclei and thereby pose a radiation hazard which is not assessable by conventional dosimetry. Survival data, ...

journal_title：Physics in medicine and biology

authors： Younis AR,Watt DE

更新日期：1989-07-01 00:00:00

abstract：:In vivo neutron activation analysis was used to measure total body sodium and chlorine in 18 male and 18 female normal adults. Corrections for body size were developed. Normalisation factors were derived which enable the prediction of the normal levels of sodium and chlorine in a subject. The coefficient of variation ...

journal_title：Physics in medicine and biology

authors： Kennedy NS,Eastell R,Smith MA,Tothill P

更新日期：1983-03-01 00:00:00

abstract：:Compressed sensing (CS) aims to recover images from fewer measurements than that governed by the Nyquist sampling theorem. Most CS methods use analytical predefined sparsifying domains such as total variation, wavelets, curvelets, and finite transforms to perform this task. In this study, we evaluated the use of dicti...

journal_title：Physics in medicine and biology

authors： Valiollahzadeh S,Clark JW,Mawlawi O

更新日期：2015-08-07 00:00:00

abstract：:Quantifying the retention or washout of (99m)Tc-Sestamibi (MIBI) in breast tumours in vivo may provide a basis for predicting the chemotherapy response. The aim of this study is to investigate the variations and limitations of the different methods used to quantify these parameters. A phantom was developed that allowe...

journal_title：Physics in medicine and biology

authors： Marshall C,Griffiths PA

更新日期：2005-05-07 00:00:00

abstract：:Time-of-flight (TOF) positron emission tomography (PET) technology has recently regained popularity in clinical PET studies for improving image quality and lesion detectability. Using TOF information, the spatial location of annihilation events is confined to a number of image voxels along each line of response, there...

journal_title：Physics in medicine and biology

authors： Mehranian A,Kotasidis F,Zaidi H

更新日期：2016-02-07 00:00:00

abstract：:The treatment delivery time of intensity-modulated radiation therapy (IMRT) with a multileaf collimator (MLC) is generally longer than that of conventional radiotherapy. In theory, removing the flattening filter from the treatment head may reduce the beam-on time by enhancing the output dose rate, and then reduce the ...

journal_title：Physics in medicine and biology

authors： Fu W,Dai J,Hu Y,Han D,Song Y

更新日期：2004-04-21 00:00:00

abstract：:Modern Monte Carlo codes allow for the calculation of ion chamber specific beam quality correction factors k(Q), which are needed for dosimetry in radiotherapy. While statistical (type A) uncertainties of the calculated data can be minimized sufficiently, the influence of systematic (type B) uncertainties is mostly un...

journal_title：Physics in medicine and biology

authors： Wulff J,Heverhagen JT,Zink K,Kawrakow I

更新日期：2010-08-21 00:00:00

abstract：:Transverse image truncation can be a serious problem for human imaging using cone-beam transmission CT (CB-CT) implemented on a conventional rotating gamma camera. If this problem can be solved, CB-CT will be useful for attenuation compensation of SPECT images. This paper presents a reconstruction method to reduce or ...

journal_title：Physics in medicine and biology

authors： Manglos SH

更新日期：1992-03-01 00:00:00

abstract：:Magnetoencephalography (MEG) is a non-invasive functional imaging modality based on the measurement of the external magnetic field produced by neural current sources within the brain. The reconstruction of the underlying sources is a severely ill-posed inverse problem typically tackled using either low-dimensional par...

journal_title：Physics in medicine and biology

authors： Jerbi K,Mosher JC,Baillet S,Leahy RM

更新日期：2002-02-21 00:00:00

abstract：:The advent of real-time ultrasound in the 1970s, together with a growing interest in tissue characterization, led to a number of investigators using the nature of tissue motion to distinguish healthy from diseased tissue. Our group at the (then) Ultrasonics Institute demonstrated the use of phase methods for detecting...

journal_title：Physics in medicine and biology

authors： Wilson LS,Robinson DE,Dadd MJ

更新日期：2000-06-01 00:00:00