Abstract:
PURPOSE:Repeated brain MRI scans are performed in many clinical scenarios, such as follow up of patients with tumors and therapy response assessment. In this paper, the authors show an approach to utilize former scans of the patient for the acceleration of repeated MRI scans. METHODS:The proposed approach utilizes the possible similarity of the repeated scans in longitudinal MRI studies. Since similarity is not guaranteed, sampling and reconstruction are adjusted during acquisition to match the actual similarity between the scans. The baseline MR scan is utilized both in the sampling stage, via adaptive sampling, and in the reconstruction stage, with weighted reconstruction. In adaptive sampling, k-space sampling locations are optimized during acquisition. Weighted reconstruction uses the locations of the nonzero coefficients in the sparse domains as a prior in the recovery process. The approach was tested on 2D and 3D MRI scans of patients with brain tumors. RESULTS:The longitudinal adaptive compressed sensing MRI (LACS-MRI) scheme provides reconstruction quality which outperforms other CS-based approaches for rapid MRI. Examples are shown on patients with brain tumors and demonstrate improved spatial resolution. Compared with data sampled at the Nyquist rate, LACS-MRI exhibits signal-to-error ratio (SER) of 24.8 dB with undersampling factor of 16.6 in 3D MRI. CONCLUSIONS:The authors presented an adaptive method for image reconstruction utilizing similarity of scans in longitudinal MRI studies, where possible. The proposed approach can significantly reduce scanning time in many applications that consist of disease follow-up and monitoring of longitudinal changes in brain MRI.
journal_name
Med Physjournal_title
Medical physicsauthors
Weizman L,Eldar YC,Ben Bashat Ddoi
10.1118/1.4928148subject
Has Abstractpub_date
2015-09-01 00:00:00pages
5195-208issue
9eissn
0094-2405issn
2473-4209journal_volume
42pub_type
杂志文章相关文献
MEDICAL PHYSICS文献大全abstract::Manganese (Mn) is an essential nutrient for growth and development. Unfortunately, overexposure can lead to neurological damage, which is manifested as a movement disorder marked by tremors. Preclinical symptoms have been found in populations occupationally exposed to the element, and it is suggested that in late stag...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.1517613
更新日期:2002-11-01 00:00:00
abstract:PURPOSE:Plastic scintillation detectors are used for dosimetry in small radiation fields with high dose gradients, e.g., provided by β-emitting sources like 106 Ru/106 Rh eye plaques. A drawback is a background signal caused by Cerenkov radiation generated by electrons passing the optical fibers (light guides) of this ...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1002/mp.12374
更新日期:2017-09-01 00:00:00
abstract::We propose the use of conic and cubic surface equations (surfaces of second and third order) to directly approximate the dual-energy equations (the integral equations for the dual-energy log-signal functions, i.e., the negative logarithms of the relative detector signals, considered as functions of the basis-material ...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.596512
更新日期:1990-05-01 00:00:00
abstract:PURPOSE:The objective of this study is to evaluate requirements for radionuclide-based solid tumor therapy by assessing the radial dose distribution of beta-particle-emitting and alpha-particle-emitting molecules localized either solely within endothelial cells of tumor vasculature or diffusing from the vasculature thr...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.3431999
更新日期:2010-06-01 00:00:00
abstract::The number of intensity modulated radiation therapy (IMRT) procedures is continuously growing worldwide and it is necessary to develop tools for patient specific quality assurance (QA) that avoid using machine time that could be employed in treating additional patients. One way of achieving this goal is to perform a m...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.2815359
更新日期:2008-01-01 00:00:00
abstract::A commercial optical system developed by Solid Photography, Inc., has been used to generate precise paraffin--polyethylene tissue compensators. A program with the objective of constructing a medical facility has been undertaken to access patient topology for treatment planning, tissue-compensator fabrication, and pati...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.594447
更新日期:1978-11-01 00:00:00
abstract::We designed a questionnaire to be filled out by the physicist at the time of planning treatment with the aid of a computer in order to assess what was learned during the course of the planning session. We analyzed the results to gauge the impact of the 70 treatment planning sessions conducted during the one month peri...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.596302
更新日期:1988-03-01 00:00:00
abstract:PURPOSE:The electronic portal imaging device (EPID) is a system for checking the patient setup; as a result of its integration with the linear accelerator and software customized for dosimetry, it is increasingly used for verification of the delivery of fixed-field intensity-modulated radiation therapy (IMRT). In order...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.3271107
更新日期:2010-01-01 00:00:00
abstract::A conceptual design is presented showing that, by judiciously choosing the beryllium target thickness and the backstop material, improvements can be achieved in dose-rate, skin sparing, and penetration of neutron beams generated by the same proton accelerator. ...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.594748
更新日期:1980-09-01 00:00:00
abstract:PURPOSE:A dynamic bowtie filter can modulate flux along both fan and view angles for reduced patient dose, scatter, and required photon flux, which is especially important for photon counting detectors (PCDs). Among the proposed dynamic bowtie designs, the piecewise-linear attenuator (Hsieh and Pelc, Med Phys. 2013;40:...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1002/mp.13272
更新日期:2019-01-01 00:00:00
abstract:PURPOSE:A high resolution, water equivalent, optical and passive x-ray dosimeter has been constructed using plastic scintillator and optical fiber. This dosimeter has a peak edge-on spatial resolution of 100 μm in one dimension, with a 10 μm resolution dosimeter under investigation. The dosimeter design has a potential...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1002/mp.12209
更新日期:2017-05-01 00:00:00
abstract:PURPOSE:To achieve more translatable preclinical research results, small animal irradiation needs to more closely simulate human radiotherapy. Although the clinical gold standard is intensity-modulated radiation therapy (IMRT), the direct translation of this method for small animals is impractical. In this study we des...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1002/mp.13872
更新日期:2019-12-01 00:00:00
abstract::Functional single photon emission computed tomography (SPECT) images of brain activation are based on a comparison of base line and activation images. The correctness of the functional images depends, among other factors, on the accurate spatial registration (alignment) of the base line and activation image data. The ...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.597412
更新日期:1994-10-01 00:00:00
abstract:PURPOSE:In using flat panel detectors (FPD) for cone beam computed tomography (CBCT), pixel gain variations may lead to structured nonuniformities in projections and ring artifacts in CBCT images. Such gain variations can be caused by change in detector entrance exposure levels or beam hardening, and they are not accou...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4893278
更新日期:2014-09-01 00:00:00
abstract:PURPOSE:Positron emission tomography (PET) is considered the gold standard for measuring myocardial blood flow in vivo but it is known that respiratory motion can lead to misalignment of the PET and computed tomography (CT) data sets and introduce artifacts in the CT-based attenuation correction (AC) of images. In addi...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4788669
更新日期:2013-02-01 00:00:00
abstract::Human tumors are characterized by an abnormal vascular network that develops because of unregulated angiogenesis. This contributes to abnormalities of the tumor microenvironment like hypoxia, acidosis and high interstitial fluid pressure that influence treatment response and patient survival. There is an important cli...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4736156
更新日期:2012-06-01 00:00:00
abstract::Current dosimetry protocols for clinical protons do not take into account any secondary electron fluence perturbation in ion chambers. In this work, we performed a systematic study of secondary electron fluence perturbation factors for spherical and cylindrical ion chambers in proton beams (70-250 MeV). The electron f...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.1406519
更新日期:2001-10-01 00:00:00
abstract::Using superior localization and immobilization methods, stereotactic radiosurgery is capable of delivering spheres of dose as small as a few millimetres in diameter to intracranial targets. For targets abutting critical structures, the most conformal treatments minimize adverse radiation side effects and it is importa...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.2965910
更新日期:2008-07-01 00:00:00
abstract::Quantitation of planar radionuclide images is hampered by structures containing radioactivity which overlie or underlie the organ of interest. The introduction of single photon emission computerized tomography (SPECT) overcame this problem to a large extent and enhanced the contrast of the images. Attenuation of photo...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.596684
更新日期:1991-05-01 00:00:00
abstract::Spread of invasive carcinoma throughout breast tissue is believed to occur at supramolecular levels, beyond the range of standard histopathology identification. Small angle x-ray scattering (SAXS) is capable of characterizing the structural properties of collagen and tissue found in the breast at the scale of tens to ...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.3147144
更新日期:2009-07-01 00:00:00
abstract::CEA TVS film is a therapy verification film that has been recently introduced in the North American market. This film features linear characteristic curves for photon energies from 137Cs to 18 MV as reported by Cheng and Das [Med. Phys. 23, 1225 (1996)]. In Saskatoon, TVS film was investigated for its application in t...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.598316
更新日期:1998-08-01 00:00:00
abstract:PURPOSE:At our institution, all proton patient plans undergo patient-specific quality assurance (PSQA) prior to treatment delivery. For intensity-modulated proton beam therapy, quality assurance is complex and time consuming, and it may involve multiple measurements per field. We reviewed our PSQA workflow and identifi...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1002/mp.13246
更新日期:2019-01-01 00:00:00
abstract:PURPOSE:The efficiency of radioembolization procedures could be greatly enhanced if results of the 99m Tc-MAA pretreatment procedure were immediately available in the interventional suite, enabling 1-day procedures as a result of direct estimation of the hepatic radiation dose and lung shunt fraction. This would, howev...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1002/mp.13253
更新日期:2019-01-01 00:00:00
abstract:PURPOSE:High-intensity focused ultrasound (HIFU) has been investigated for ablative therapy and drug enhancement for gene therapy and chemotherapy. The aim of this work is to explore the feasibility of pulsed focused ultrasound (pFUS) for cancer therapy using an in vivo animal model. METHODS:A clinical HIFU system (In...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4901352
更新日期:2014-12-01 00:00:00
abstract:PURPOSE:The ability to monitor intrafractional tumor motion is essential for radiation therapy of thoracic and abdominal tumors. This study aims to develop a method to track lung tumor motion using intrafractional continuous ultrasound (US) and periodic cone-beam projection images (CBPI). METHODS:Time-sequenced b-mode...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1002/mp.13104
更新日期:2018-10-01 00:00:00
abstract::A new system of radiation dose mapping based on laser heating of thermoluminescent dosimetric plates (TLDP) has been developed. Application of this technique to intraoperative radiotherapy (IORT) has been investigated. Preliminary results show that TLDP are a possible alternative to radiological films and ionization c...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.597725
更新日期:1996-08-01 00:00:00
abstract::Total scalp irradiation is a treatment technique used for a variety of superficial malignancies. Helical tomotherapy is an effective technique used for total scalp irradiation. Recent published work has shown the TomoTherapy planning system to overestimate the superficial dose. In this study, the superficial doses for...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.2996288
更新日期:2008-11-01 00:00:00
abstract::In conventional dose optimization algorithms, in brachytherapy, multiple objectives are expressed in terms of an aggregating function which combines individual objective values into a single utility value, making the problem single objective, prior to optimization. A multiobjective genetic algorithm (MOGA) was develop...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.598697
更新日期:1999-09-01 00:00:00
abstract::Intraoperative three-dimensional reconstruction of seed locations during prostate brachytherapy for purposes of immediate computation of radiation dosimetry is an active area of current investigation, including methods which use multiple fluoroscopic projections. A simulation study using seed locations extracted from ...
journal_title:Medical physics
pub_type: 临床试验,杂志文章
doi:10.1118/1.1707740
更新日期:2004-05-01 00:00:00
abstract:PURPOSE:Many clinical applications depend critically on the accurate differentiation and classification of different types of materials in patient anatomy. This work introduces a unified framework for accurate nonlinear material decomposition and applies it, for the first time, in the concept of triple-energy CT (TECT)...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1002/mp.12933
更新日期:2018-07-01 00:00:00