18251
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Wiksell H, Ekstrand V, Wadström C, Auer G. A new semi-automated instrument to improve the fine needle aspiration procedure during breast lesion cell sampling. Phys Med 2009; 25:128-32. [DOI: 10.1016/j.ejmp.2008.09.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2008] [Revised: 09/15/2008] [Accepted: 09/17/2008] [Indexed: 11/26/2022] Open
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18252
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TYAGI P, CHUANG YC, YOSHIMURA N, KAUFMANN J, CHANCELLOR MB. Bladder Instillation of Liposomes for Bladder Coating and Drug Delivery Platform. Low Urin Tract Symptoms 2009. [DOI: 10.1111/j.1757-5672.2009.00040.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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18253
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Montella S, Santamaria F, Salvatore M, Maglione M, Iacotucci P, De Santi MM, Mollica C. Lung disease assessment in primary ciliary dyskinesia: a comparison between chest high-field magnetic resonance imaging and high-resolution computed tomography findings. Ital J Pediatr 2009; 35:24. [PMID: 19660117 PMCID: PMC2737542 DOI: 10.1186/1824-7288-35-24] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2009] [Accepted: 08/06/2009] [Indexed: 11/13/2022] Open
Abstract
Background Primary ciliary dyskinesia (PCD) is associated with pulmonary involvement that requires periodical assessment. Chest high-resolution computed tomography (HRCT) has become the method of choice to evaluate chronic lung disease, but entails exposure to ionizing radiation. Magnetic resonance imaging (MRI) has been proposed as a potential radiation-free technique in several chest disorders. Aim of our study is to evaluate whether high-field MRI is as effective as HRCT in identifying PCD pulmonary abnormalities. We also analyzed the relationships between the severity and extension of lung disease, and functional data. Methods Thirteen PCD patients (8 children/5 adults; median age, 15.2 yrs) underwent chest HRCT and high-field 3T MRI, spirometry, and deep throat or sputum culture. Images were scored using a modified version of the Helbich system. Results HRCT and MRI total scores were 12 (range, 6–20) and 12 (range, 5–17), respectively. Agreement between HRCT and MRI scores was good or excellent (r > 0.8). HRCT and MRI total scores were significantly related to forced vital capacity (r = -0.5, p = 0.05; and r = -0.7, p = 0.009, respectively) and forced expiratory volume at 1 second (r = -0.6, p = 0.03; and r = -0.7, p = 0.009, respectively). Conclusion Chest high-field 3T MRI appears to be as effective as HRCT in assessing the extent and severity of lung abnormalities in PCD. MRI scores might be used for longitudinal assessment and be an outcome surrogate in future studies.
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Affiliation(s)
- Silvia Montella
- Department of Paediatrics, University of Naples Federico II, Naples, Italy.
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18254
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Abstract
This review examines the state of the art in vessel wall imaging by magnetic resonance imaging (MRI) with an emphasis on the biomechanical assessment of atherosclerotic plaque. Three areas of advanced techniques are discussed. First, alternative contrast mechanisms, including susceptibility, magnetization transfer, diffusion, and perfusion, are presented as to how they facilitate accurate determination of plaque constituents underlying biomechanics. Second, imaging technologies including hardware and sequences, are reviewed as to how they provide the resolution and signal-to-noise ratio necessary for determining plaque structure. Finally, techniques for combining MRI data into an overall assessment of plaque biomechanical properties, including wall shear stress and internal plaque strain, are presented. The paper closes with a discussion of the extent to which these techniques have been applied to different arteries commonly targeted by vessel wall MRI.
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Affiliation(s)
- William S Kerwin
- Department of Radiology, University of Washington, Seattle, WA 98109, USA.
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18255
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McNamee JP, Flegal FN, Greene HB, Marro L, Wilkins RC. Validation of the cytokinesis-block micronucleus (CBMN) assay for use as a triage biological dosimetry tool. RADIATION PROTECTION DOSIMETRY 2009; 135:232-242. [PMID: 19628702 DOI: 10.1093/rpd/ncp119] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Traditionally, the dicentric chromosome assay (DCA) has been used to derive biological dose estimates for unknown radiological exposures. While sensitive, this assay requires highly trained evaluators and is extremely time consuming. The cytokinesis-block micronucleus (CBMN) assay has been suggested as an alternative to the DCA, as it is much faster to evaluate samples and requires less technical expertise. In order to validate this assay for triage biodosimetry, dose-response curves were generated for six donors at eight doses of gamma-radiation (0-4.0 Gy). Each sample was evaluated by 12 individuals, among three different laboratories and the incidence of micronuclei was determined after counting 50-500 binucleated cells. This study demonstrated that the CBMN assay was capable of detecting radiation doses >or=1 Gy after scoring only 200 binucleated cells. As such, the CBMN assay may provide a sensitive and reliable technique for deployment as an initial screening tool in a large-scale radiological emergency where large numbers of biological dose estimates are required.
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Affiliation(s)
- James P McNamee
- Consumer and Clinical Radiation Protection Bureau, Healthy Environment and Consumer Safety Branch, Health Canada, Ottawa, ON, Canada.
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18256
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Kiviniemi V, Remes J, Starck T, Nikkinen J, Haapea M, Silven O, Tervonen O. Mapping Transient Hyperventilation Induced Alterations with Estimates of the Multi-Scale Dynamics of BOLD Signal. Front Neuroinform 2009; 3:18. [PMID: 19636388 PMCID: PMC2715265 DOI: 10.3389/neuro.11.018.2009] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2009] [Accepted: 06/22/2009] [Indexed: 11/24/2022] Open
Abstract
Temporal blood oxygen level dependent (BOLD) contrast signals in functional MRI during rest may be characterized by power spectral distribution (PSD) trends of the form 1/f(alpha). Trends with 1/f characteristics comprise fractal properties with repeating oscillation patterns in multiple time scales. Estimates of the fractal properties enable the quantification of phenomena that may otherwise be difficult to measure, such as transient, non-linear changes. In this study it was hypothesized that the fractal metrics of 1/f BOLD signal trends can map changes related to dynamic, multi-scale alterations in cerebral blood flow (CBF) after a transient hyperventilation challenge. Twenty-three normal adults were imaged in a resting-state before and after hyperventilation. Different variables (1/f trend constant alpha, fractal dimension D(f), and, Hurst exponent H) characterizing the trends were measured from BOLD signals. The results show that fractal metrics of the BOLD signal follow the fractional Gaussian noise model, even during the dynamic CBF change that follows hyperventilation. The most dominant effect on the fractal metrics was detected in grey matter, in line with previous hyperventilation vaso-reactivity studies. The alpha was able to differentiate also blood vessels from grey matter changes. D(f) was most sensitive to grey matter. H correlated with default mode network areas before hyperventilation but this pattern vanished after hyperventilation due to a global increase in H. In the future, resting-state fMRI combined with fractal metrics of the BOLD signal may be used for analyzing multi-scale alterations of cerebral blood flow.
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Affiliation(s)
- Vesa Kiviniemi
- Department of Diagnostic Radiology, Oulu University HospitalOulu, Finland
| | - Jukka Remes
- Department of Diagnostic Radiology, Oulu University HospitalOulu, Finland
- Department of Information and Electrical Engineering, University of OuluOulu, Finland
| | - Tuomo Starck
- Department of Diagnostic Radiology, Oulu University HospitalOulu, Finland
| | - Juha Nikkinen
- Department of Diagnostic Radiology, Oulu University HospitalOulu, Finland
| | - Marianne Haapea
- Department of Diagnostic Radiology, Oulu University HospitalOulu, Finland
| | - Olli Silven
- Department of Information and Electrical Engineering, University of OuluOulu, Finland
| | - Osmo Tervonen
- Department of Diagnostic Radiology, Oulu University HospitalOulu, Finland
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18257
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Bor D, Olgar T, Onal E, Caglan A, Toklu T. Assessment of radiation doses to cardiologists during interventional examinations. Med Phys 2009; 36:3730-6. [DOI: 10.1118/1.3168971] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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18258
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Muren LP, Petersen JB, Hansen J, Hafslund R. Medical physics in the Nordic countries: the past, the present and the future. Acta Oncol 2009; 48:165-8. [PMID: 19031283 DOI: 10.1080/02841860802558946] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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18259
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Røthe Arnesen M, Eilertsen K, Malinen E. Optimal treatment margins for radiotherapy of prostate cancer based on interfraction imaging. Acta Oncol 2009; 47:1373-81. [PMID: 18654907 DOI: 10.1080/02841860802244190] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
PURPOSE To present a methodology to estimate optimal treatment margins for radiotherapy of prostate cancer based on interfraction imaging. MATERIALS AND METHODS Cone beam CT images of a prostate cancer patient undergoing fractionated radiotherapy were acquired at all treatment sessions. The clinical target volume (CTV) and organs at risk (OARs; bladder and rectum) were delineated in the images. Random sampling from the CTV-OAR library was performed in order to simulate fractionated radiotherapy including intra- and interpatient variability in setup and organ motion/deformation. For each simulated patient, four treatment fields defined by multileaf collimators were automatically generated around the planning CTV. The treatment margin (the distance from the CTV to the field border) was varied between 2.5 and 20 mm. Resulting dose distributions were calculated by a convolution method. Doses to OARs were reconstructed by polynomial warping, while the CTV was assumed to be a rigid body. The equivalent uniform dose (EUD), the tumor control probability (TCP) and the normal tissue complication probability (NTCP) were used to estimate the clinical effect. Patient repositioning strategies at treatment were compared. RESULTS The simulations produced population based EUD histograms for the CTV and the OARs. The number of patients receiving an optimal target EUD increased with increasing margins, but at the cost of an increasing number receiving a high EUD to the OARs. Calculations of the probability of complication-free tumor control and subsequent analysis gave an optimal treatment margin of about 10mm for the simulated population, if no correction strategy was undertaken. CONCLUSIONS The current work illustrates the principle of optimal treatment margins based on interfraction imaging. Clinically applicable margins may be obtained if a large patient image database is available.
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18260
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Abstract
This is an "Opinion" or "Commentary" text to support the Invited Opening Plenary Lecture of the NACP2008 Conference. It is an outrageously broad title, that I have been given, and I have made selections for the focus of the lecture and for this report. I observe a research methodology in medical physics whereby key developments have come from standing on the shoulders of those who have come before and I illustrate this by the invention of x-ray computed tomography and the development of intensity-modulated radiation therapy. The equally key role of somewhat maligned incremental science is also discussed. Some commentary is made on the enormous range of activities in medicine to which medical physicists have contributed. Conversely, future gazing is a totally unscientific process. Nevertheless I add my thoughts in broad generalities and also in specifics for the field (radiotherapy physics) in which I work and might be expected to be more accurate in my proposals. I conclude with some remarks on the conditions needed to achieve good scientific outcome.
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18261
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Yang L, Peng XH, Wang YA, Wang X, Cao Z, Ni C, Karna P, Zhang X, Wood WC, Gao X, Nie S, Mao H. Receptor-targeted nanoparticles for in vivo imaging of breast cancer. Clin Cancer Res 2009; 15:4722-32. [PMID: 19584158 DOI: 10.1158/1078-0432.ccr-08-3289] [Citation(s) in RCA: 180] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
PURPOSE Cell-surface receptor-targeted magnetic iron oxide nanoparticles provide molecular magnetic resonance imaging contrast agents for improving specificity of the detection of human cancer. EXPERIMENTAL DESIGN The present study reports the development of a novel targeted iron oxide nanoparticle using a recombinant peptide containing the amino-terminal fragment of urokinase-type plasminogen activator (uPA) conjugated to magnetic iron oxide nanoparticles amino-terminal fragment conjugated-iron oxide (ATF-IO). This nanoparticle targets uPA receptor, which is overexpressed in breast cancer tissues. RESULTS ATF-IO nanoparticles are able to specifically bind to and be internalized by uPA receptor-expressing tumor cells. Systemic delivery of ATF-IO nanoparticles into mice bearing s.c. and i.p. mammary tumors leads to the accumulation of the particles in tumors, generating a strong magnetic resonance imaging contrast detectable by a clinical magnetic resonance imaging scanner at a field strength of 3 tesla. Target specificity of ATF-IO nanoparticles showed by in vivo magnetic resonance imaging is further confirmed by near-IR fluorescence imaging of the mammary tumors using near-IR dye-labeled amino-terminal fragment peptides conjugated to iron oxide nanoparticles. Furthermore, mice administered ATF-IO nanoparticles exhibit lower uptake of the particles in the liver and spleen compared with those receiving nontargeted iron oxide nanoparticles. CONCLUSIONS Our results suggest that uPA receptor-targeted ATF-IO nanoparticles have potential as molecularly targeted, dual modality imaging agents for in vivo imaging of breast cancer.
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Affiliation(s)
- Lily Yang
- Department of Surgery and Winship Cancer Institute, Emory University School of Medicine, C-4088, 1365 C Clifton Road NE, Atlanta, GA 30322, USA.
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18262
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Huang Q, Xu J, Tsui BMW, Gullberg GT. Reconstructing uniformly attenuated rotating slant-hole SPECT projection data using the DBH method. Phys Med Biol 2009; 54:4325-39. [PMID: 19531850 DOI: 10.1088/0031-9155/54/13/024] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
This work applies a previously developed analytical algorithm to the reconstruction problem in a rotating multi-segment slant-hole (RMSSH) SPECT system. The RMSSH collimator has greater detection efficiency than the parallel-hole collimator with comparable spatial resolution at the expense of limited common volume-of-view (CVOV) and is therefore suitable for detecting low-contrast lesions in breast, cardiac and brain imaging. The absorption of gamma photons in both the human breast and brain can be assu- med to follow an exponential rule with a constant attenuation coefficient. In this work, the RMSSH SPECT data of a digital NCAT phantom with breast attachment are modeled as the uniformly attenuated Radon transform of the activity distribution. These data are reconstructed using an analytical algorithm called the DBH method, which is an acronym for the procedure of differentiation backprojection followed by a finite weighted inverse Hilbert transform. The projection data are first differentiated along a specific direction in the projection space and then backprojected to the image space. The result from this first step is equal to a one-dimensional finite weighted Hilbert transform of the object; this transform is then numerically inverted to obtain the reconstructed image. With the limited CVOV of the RMSSH collimator, the detector captures gamma photon emissions from the breast and from parts of the torso. The simulation results show that the DBH method is capable of exactly reconstructing the activity within a well-defined region-of-interest (ROI) within the breast if the activity is confined to the breast or if the activity outside the CVOV is uniformly attenuated for each measured projection, while a conventional filtered backprojection algorithm only reconstructs the high frequency components of the activity function in the same geometry.
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Affiliation(s)
- Qiu Huang
- The E O Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
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18263
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Deak PD, Langner O, Lell M, Kalender WA. Effects of Adaptive Section Collimation on Patient Radiation Dose in Multisection Spiral CT. Radiology 2009; 252:140-7. [DOI: 10.1148/radiol.2522081845] [Citation(s) in RCA: 131] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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18264
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Blair A, Meyer J. Characteristics of Gafchromic®
XR-RV2 radiochromic film. Med Phys 2009; 36:3050-8. [DOI: 10.1118/1.3147141] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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18265
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Baldock C. Historical overview of the development of gel dosimetry: Another personal perspective. ACTA ACUST UNITED AC 2009. [DOI: 10.1088/1742-6596/164/1/012002] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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18266
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Monici M, Fusi F, Paglierani M, Marziliano N, Cogoli A, Pratesi R, Bernabei PA. Modeled gravitational unloading triggers differentiation and apoptosis in preosteoclastic cells. J Cell Biochem 2009; 98:65-80. [PMID: 16365883 DOI: 10.1002/jcb.20747] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Gravity acts permanently on organisms as either static or dynamic stimulation. Understanding the influence of gravitational and mechanical stimuli on biological systems is an intriguing scientific problem. More than two decades of life science studies in low g, either real or modeled by clinostats, as well as experimentation with devices simulating different types of controlled mechanical stimuli, have shown that important biological functions are altered at the single cell level. Here, we show that the human leukemic line FLG 29.1, characterized as an osteoclastic precursor model, is directly sensitive to gravitational unloading, modeled by a random positioning machine (RPM). The phenotypic expression of cytoskeletal proteins, osteoclastic markers, and factors regulating apoptosis was investigated using histochemical and immunohistochemical methods, while the expression of the corresponding genes was analyzed using RT-PCR. A quantitative bone resorption assay was performed. Autofluorescence spectroscopy and imaging were applied to gain information on cell metabolism. The results show that modeled hypogravity may trigger both differentiation and apoptosis in FLG 29.1 cells. Indeed, when comparing RPM versus 1 x g cultures, in the former we found cytoskeletal alterations and a marked increase in apoptosis, but the surviving cells showed an osteoclastic-like morphology, overexpression of osteoclastic markers and the ability to resorb bone. In particular, the overexpression of both RANK and its ligand RANKL, maintained even after return to 1 x g conditions, is consistent with the firing of a differentiation process via a paracrine/autocrine mechanism.
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Affiliation(s)
- Monica Monici
- CEO--Center of Excellence in Optronics, L. Enrico Fermi 6, I-50125 Florence, Italy.
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18267
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Margel D, Harel A, Yossepowitch O, Baniel J. A novel algorithm to improve pathologic stage prediction of clinically organ-confined muscle-invasive bladder cancer. Cancer 2009; 115:1459-64. [PMID: 19152435 DOI: 10.1002/cncr.24138] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
BACKGROUND An algorithm was created to predict pathologic stage in patients with clinically organ-confined muscle-invasive bladder cancer. METHODS The sample consisted of 133 consecutive patients scheduled to undergo cystectomy. To develop a tool to predict nonorgan-confined disease before surgery, principal component analysis (PCA) was applied. Patients were stratified into a training set (n = 89) and a validation set (n = 44), and 7 parameters were evaluated: levels of carcinoembryonic antigen, cancer antigen (CA) 125, and carbohydrate antigen (CA) 19-9; clinical stage; presence of hydronephrosis; presence of carcinoma in situ; and initial tumor size >3 cm. PCA was applied to the training set to determine the weight of each parameter. A PCA score was generated for each patient in the set, and a cutoff defining nonorgan-confined disease was established. The accuracy of the cutoff was quantified by the area under the receiver operator characteristics curve (AUC). The model was then applied to the validation set without recalculation; the AUC and the positive and negative predictive values of the validation set were calculated. RESULTS On pathologic evaluation, 71 patients (53%) were found to have organ-confined tumors and 62 patients (47%) had extravesical disease. The AUC was 0.85 in the training group (95% confidence interval [95% CI], 0.71-0.97) and 0.84 in the validation group (95% CI, 0.75-0.93). The positive and negative predictive values in the validation group were 88% (95% CI, 71%-96%) and 94% (95% CI, 71%-99%), respectively. CONCLUSIONS The newly devised, internally validated, algorithm was 85% accurate in predicting nonorgan-confined bladder disease before cystectomy. Further external validation in a large cohort was recommended as still necessary.
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Affiliation(s)
- David Margel
- Institute of Urology, Rabin Medical Center, Beilinson Campus, Petach Tikva, Israel.
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18268
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Salinas FS, Lancaster JL, Fox PT. 3D modeling of the total electric field induced by transcranial magnetic stimulation using the boundary element method. Phys Med Biol 2009; 54:3631-47. [PMID: 19458407 DOI: 10.1088/0031-9155/54/12/002] [Citation(s) in RCA: 94] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Transcranial magnetic stimulation (TMS) delivers highly localized brain stimulations via non-invasive externally applied magnetic fields. This non-invasive, painless technique provides researchers and clinicians with a unique tool capable of stimulating both the central and peripheral nervous systems. However, a complete analysis of the macroscopic electric fields produced by TMS has not yet been performed. In this paper, we addressed the importance of the secondary E-field created by surface charge accumulation during TMS using the boundary element method (BEM). 3D models were developed using simple head geometries in order to test the model and compare it with measured values. The effects of tissue geometry, size and conductivity were also investigated. Finally, a realistically shaped head model was used to assess the effect of multiple surfaces on the total E-field. Secondary E-fields have the greatest impact at areas in close proximity to each tissue layer. Throughout the head, the secondary E-field magnitudes typically range from 20% to 35% of the primary E-field's magnitude. The direction of the secondary E-field was generally in opposition to the primary E-field; however, for some locations, this was not the case (i.e. going from high to low conductivity tissues). These findings show that realistically shaped head geometries are important for accurate modeling of the total E-field.
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Affiliation(s)
- F S Salinas
- Research Imaging Center, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
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18269
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Takeda A, Kunieda E, Sanuki N, Ohashi T, Oku Y, Sudo Y, Iwashita H, Ooka Y, Aoki Y, Shigematsu N, Kubo A. Dose distribution analysis in stereotactic body radiotherapy using dynamic conformal multiple arc therapy. Int J Radiat Oncol Biol Phys 2009; 74:363-9. [PMID: 19427552 DOI: 10.1016/j.ijrobp.2008.08.012] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2008] [Revised: 08/18/2008] [Accepted: 08/18/2008] [Indexed: 12/25/2022]
Abstract
PURPOSE We have used dynamic conformal multiple arc therapy (DCMAT) for stereotactic body radiotherapy (SBRT) since 2001. We investigated the consistency of DCMAT for SBRT using dose-volume histogram analysis. METHODS AND MATERIALS A total of 50 patients with peripheral lung tumors underwent SBRT. The median tumor diameter was 2.4 cm (range, 0.9-5.9). Treatment planning was performed using a superposition algorithm. The prescribed 50 Gy dose was divided into five fractions. The prescribed dose was defined as 80% of the maximal dose in the planning target volume (PTV), and the leaf margins were modified to ensure the PTV was included in the 80% isodose surface. The dose-volume histogram analysis was used to assess the PTV and normal lung volume. RESULTS The median dose covering 95% of the PTV was 50.27 Gy (range, 46.14-52.67), essentially consistent with the prescribed dose. The median homogeneity and conformity index was 1.41 (range, 1.31-1.53) and 1.73 (range, 1.41-2.21), respectively. The median volume of lung receiving > or =20 Gy (V(20)) was 4.2% (range, 1.4-10.2%). A linear correlation was found between the tumor diameter and V(20), and an even stronger correlation was found between the PTV/(normal lung volume) and V(20). The estimated V(20) was 7.1% (range, 3.9-10.4%) for a 5-cm-diameter tumor, assumed to be the maximal size limitation for SBRT. CONCLUSION SBRT with DCMAT achieved high conformity and delivered adequate doses within the PTV. The median dose covering 95% of the PTV was consistent with the prescribed dose. V(20) can be estimated using the tumor diameter and normal lung volume. DCMAT was thus both a feasible and a reproducible method of SBRT delivery.
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Affiliation(s)
- Atsuya Takeda
- Department of Radiology, Ofuna Chuo Hospital, Kanagawa, Japan
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18270
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Piermattei A, Cilla S, Grimaldi L, Sabatino D, Fidanzio A, Greco F, Mameli A, Balducci M, Mattiucci GC, Frascino V, Stimato G, Gaudino D, Ramella S, Trodella L, D'Onofrio G, Zini G, Macchia G, Digesu’ C, Morganti AG, Clemente S, Cozzolino M, Pedicini P, Fusco V. Integration between in vivo
dosimetry and image guided radiotherapy for lung tumors. Med Phys 2009; 36:2206-14. [DOI: 10.1118/1.3129158] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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18271
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Butler WM, Stewart RR, Merrick GS. A detailed radiobiological and dosimetric analysis of biochemical outcomes in a case-control study of permanent prostate brachytherapy patients. Med Phys 2009; 36:776-87. [PMID: 19378738 DOI: 10.1118/1.3077161] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
The purpose of this study is to determine dosimetric and radiobiological predictors of biochemical control after recalculation of prostate implant dosimetry using updated AAPM Task Group 43 (TG-43) parameters and the radiobiological parameters recommended by TG-137. All biochemical failures among patients implanted with 125I Or 103Pd sources between 1994 and March 2006 were matched 2:1 with nonfailure controls. The individual matching was by risk group, radionuclide, prescribed dose, and time of implant (one match before and one after the failed patient) resulting in a median follow-up of 10.9 years. Complete dose volume histogram (DVH) data were recalculated for all 55 cases and 110 controls after updating the original source strength by the retrospectively determined ratios of TG-43. Differential DVH data were acquired in 179 increments of prostate volume versus percentage prescribed dose. At each incremental dose level i, the biologically equivalent dose BEDi, equivalent uniform dose EUDi, and tumor control probability TCPi were calculated from the implant dose plus any external beam delivered to the patient. Total BED, EUD, and TCP were then derived from the incremental values for comparison with single point dosimetric quality parameters and DVH-based averages. There was no significant difference between failures and controls in terms of total BED (143 vs 142 Gy), EUD (95 vs 94 Gy), or TCP (0.87 vs 0.89). Conditional logistic regression analysis factored out the matching variables and stratified the cohort into each case and its controls, but no radiobiological parameter was predictive of biochemical failure. However, there was a significant difference between radiobiological parameters of 125I and 103Pd due to less complete coverage of the target volume by the former isotope. The implant BED and TCP were highly correlated with the D90 and natural prescription doses and a series of mean DVH-based doses such as the harmonic mean and expressions of the generalized EUD. In this case-control study of prostate brachytherapy biochemical failures and nonfailures, there were no radiobiological parameters derived from detailed DVH-based analysis that predicted for biochemical control. This may indicate that in our approach, implant dosimetry is at or near the limits of clinically effective dose escalation.
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Affiliation(s)
- Wayne M Butler
- Schiffier Cancer Center, Wheeling Hospital, 1 Medical Park, Wheeling, West Virginia 26003-6300, USA.
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18272
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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. Photoelectric-enhanced radiation therapy with quasi-monochromatic computed tomography. Med Phys 2009; 36:2107-17. [DOI: 10.1118/1.3125137] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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18273
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Caprile P, Hartmann GH. Development and validation of a beam model applicable to small fields. Phys Med Biol 2009; 54:3257-68. [DOI: 10.1088/0031-9155/54/10/020] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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18274
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Donath T, Pfeiffer F, Bunk O, Groot W, Bednarzik M, Grünzweig C, Hempel E, Popescu S, Hoheisel M, David C. Phase-contrast imaging and tomography at 60 keV using a conventional x-ray tube source. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2009; 80:053701. [PMID: 19485510 DOI: 10.1063/1.3127712] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Phase-contrast imaging at laboratory-based x-ray sources using grating interferometers has been developed over the last few years for x-ray energies of up to 28 keV. Here, we show first phase-contrast projection and tomographic images recorded at significantly higher x-ray energies, produced by an x-ray tube source operated at 100 kV acceleration voltage. We find our measured tomographic phase images in good agreement with tabulated data. The extension of phase-contrast imaging to this significantly higher x-ray energy opens up many applications of the technique in medicine and industrial nondestructive testing.
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Affiliation(s)
- Tilman Donath
- Paul Scherrer Institut, 5232 Villigen PSI, Switzerland.
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18275
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Moore MA, Wallace EC, Westra SJ. The imaging of paediatric thoracic trauma. Pediatr Radiol 2009; 39:485-96. [PMID: 19151969 DOI: 10.1007/s00247-008-1093-5] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2008] [Revised: 10/23/2008] [Accepted: 11/25/2008] [Indexed: 12/30/2022]
Abstract
Major chest trauma in a child is associated with significant morbidity and mortality. It is most frequently encountered within the context of multisystem injury following high-energy trauma such as a motor vehicle accident. The anatomic-physiologic make-up of children is such that the pattern of ensuing injuries differs from that in their adult counterparts. Pulmonary contusion, pneumothorax, haemothorax and rib fractures are most commonly encountered. Although clinically more serious and potentially life threatening, tracheobronchial tear, aortic rupture and cardiac injuries are seldom observed. The most appropriate imaging algorithm is one tailored to the individual child and is guided by the nature of the traumatic event as well as clinical parameters. Chest radiography remains the first and most important imaging tool in paediatric chest trauma and should be supplemented with US and CT as indicated. Multidetector CT allows for the accurate diagnosis of most traumatic injuries, but should be only used in selected cases as its routine use in all paediatric patients would result in an unacceptably high radiation exposure to a large number of patients without proven clinical benefit. When CT is used, appropriate modifications should be incorporated so as to minimize the radiation dose to the patient whilst preserving diagnostic integrity.
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Affiliation(s)
- Michael A Moore
- Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
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18276
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Djouguela A, Harder D, Kollhoff R, Foschepoth S, Kunth W, Rühmann A, Willborn K, Poppe B. Fourier deconvolution reveals the role of the Lorentz function as the convolution kernel of narrow photon beams. Phys Med Biol 2009; 54:2807-27. [DOI: 10.1088/0031-9155/54/9/015] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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18277
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Ristić-Fira AM, Korićanac LB, Zakula JJ, Valastro LM, Iannolo G, Privitera G, Cuttone G, Petrović IM. Effects of fotemustine or dacarbasine on a melanoma cell line pretreated with therapeutic proton irradiation. JOURNAL OF EXPERIMENTAL & CLINICAL CANCER RESEARCH : CR 2009; 28:50. [PMID: 19358719 PMCID: PMC2672057 DOI: 10.1186/1756-9966-28-50] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/06/2009] [Accepted: 04/09/2009] [Indexed: 01/30/2023]
Abstract
Background Considering that HTB140 melanoma cells have shown a poor response to either protons or alkylating agents, the effects of a combined use of these agents have been analysed. Methods Cells were irradiated in the middle of the therapeutic 62 MeV proton spread out Bragg peak (SOBP). Irradiation doses were 12 or 16 Gy and are those frequently used in proton therapy. Four days after irradiation cells were treated with fotemustine (FM) or dacarbazine (DTIC). Drug concentrations were 100 and 250 μM, values close to those that produce 50% of growth inhibition. Cell viability, proliferation, survival and cell cycle distribution were assessed 7 days after irradiation that corresponds to more than six doubling times of HTB140 cells. In this way incubation periods providing the best single effects of drugs (3 days) and protons (7 days) coincided at the same time. Results Single proton irradiations have reduced the number of cells to ~50%. FM caused stronger cell inactivation due to its high toxicity, while the effectiveness of DTIC, that was important at short term, almost vanished with the incubation of 7 days. Cellular mechanisms triggered by proton irradiation differently influenced the final effects of combined treatments. Combination of protons and FM did not improve cell inactivation level achieved by single treatments. A low efficiency of the single DTIC treatment was overcome when DTIC was introduced following proton irradiation, giving better inhibitory effects with respect to the single treatments. Most of the analysed cells were in G1/S phase, viable, active and able to replicate DNA. Conclusion The obtained results are the consequence of a high resistance of HTB140 melanoma cells to protons and/or drugs. The inactivation level of the HTB140 human melanoma cells after protons, FM or DTIC treatments was not enhanced by their combined application.
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18278
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Singh R, Kostarelos K. Designer adenoviruses for nanomedicine and nanodiagnostics. Trends Biotechnol 2009; 27:220-9. [DOI: 10.1016/j.tibtech.2009.01.003] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2008] [Revised: 01/02/2009] [Accepted: 01/07/2009] [Indexed: 01/15/2023]
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18279
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Malicki J, Litoborski M, Bogusz-Czerniewicz M, Swiezewski A. Cost-effectiveness of the modifications in the quality assurance system in radiotherapy in the example of in-vivo dosimetry. Phys Med 2009; 25:201-6. [PMID: 19286407 DOI: 10.1016/j.ejmp.2009.02.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2008] [Revised: 02/09/2009] [Accepted: 02/11/2009] [Indexed: 11/27/2022] Open
Abstract
PURPOSE To present the methodology for the evaluation of cost-effectiveness of the quality assurance protocol modifications associated with increasing demands on accuracy and reliability in radiotherapy and to present results on cost-effectiveness of in-vivo dosimetry as the chosen example of a technical procedure. MATERIAL AND METHODS In-vivo dosimetry was used as an example of a quality assurance procedure, whose modifications have an impact on several procedures in the QA system and thus on the cost of radiotherapy. An analysis of 6864 patients, treated between 2001 and 2005 for tumours in the head and neck, breast, pelvis, or lung, was performed. The quality of radiotherapy was expressed as the accuracy of dose delivery and the cost was estimated from labour, equipment and materials. RESULTS Modifications implemented in the quality assurance protocol have gradually improved the quality of irradiation. Mean deviations between measured and calculated doses, recorded for several groups of treatment sites, were reduced from -1.5% to 0.5%, 3.4% to 1.4%, 3.9% to 0.1% and -2.1% to 1.8% for head and neck, breast, pelvis and lung respectively. The standard deviations of the measured values decreased also consistently. Total monthly cost in radiotherapy (related to in-vivo dosimetry) increased from euro 4376 to euro 10,696 while the unitary cost of radiotherapy procedures remained at the same level. The predominant cost component of in-vivo dosimetry was labour, limited at first to physics staff and later extended to quality assurance personnel and technicians. CONCLUSION The application of the presented methodology revealed cost-effectiveness relationships in tested technical procedures.
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Affiliation(s)
- Julian Malicki
- Medical Physics Department, Greater Poland Cancer Centre, Poznan, Poland.
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18280
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Wattjes MP, Barkhof F. High field MRI in the diagnosis of multiple sclerosis: high field-high yield? Neuroradiology 2009; 51:279-92. [PMID: 19277621 DOI: 10.1007/s00234-009-0512-0] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2009] [Accepted: 02/11/2009] [Indexed: 10/21/2022]
Abstract
Following the approval of the U.S. Food and Drug Administration (FDA), high field magnetic resonance imaging (MRI) has been increasingly incorporated into the clinical setting. Especially in the field of neuroimaging, the number of high field MRI applications has been increased dramatically. Taking advantage on increased signal-to-noise ratio (SNR) and chemical shift, higher magnetic field strengths offer new perspectives particularly in brain imaging and also challenges in terms of several technical and physical consequences. Over the past few years, many applications of high field MRI in patients with suspected and definite multiple sclerosis (MS) have been reported including conventional and quantitative MRI methods. Conventional pulse sequences at 3 T offers higher lesion detection rates when compared to 1.5 T, particularly in anatomic regions which are important for the diagnosis of patients with MS. MR spectroscopy at 3 T is characterized by an improved spectral resolution due to increased chemical shift allowing a better quantification of metabolites. It detects significant axonal damage already in patients presenting with clinically isolated syndromes and can quantify metabolites of special interest such as glutamate which is technically difficult to quantify at lower field strengths. Furthermore, the higher susceptibility and SNR offer advantages in the field of functional MRI and diffusion tensor imaging. The recently introduced new generation of ultra-high field systems beyond 3 T allows scanning in submillimeter resolution and gives new insights into in vivo MS pathology on MRI. The objectives of this article are to review the current knowledge and level of evidence concerning the application of high field MRI in MS and to give some ideas of research perspectives in the future.
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Affiliation(s)
- Mike P Wattjes
- MS Center Amsterdam, Department of Radiology, VU University Medical Center, Amsterdam, The Netherlands.
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18281
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Pratx G, Chinn G, Olcott PD, Levin CS. Fast, accurate and shift-varying line projections for iterative reconstruction using the GPU. IEEE TRANSACTIONS ON MEDICAL IMAGING 2009; 28:435-45. [PMID: 19244015 PMCID: PMC3667989 DOI: 10.1109/tmi.2008.2006518] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
List-mode processing provides an efficient way to deal with sparse projections in iterative image reconstruction for emission tomography. An issue often reported is the tremendous amount of computation required by such algorithm. Each recorded event requires several back- and forward line projections. We investigated the use of the programmable graphics processing unit (GPU) to accelerate the line-projection operations and implement fully-3D list-mode ordered-subsets expectation-maximization for positron emission tomography (PET). We designed a reconstruction approach that incorporates resolution kernels, which model the spatially-varying physical processes associated with photon emission, transport and detection. Our development is particularly suitable for applications where the projection data is sparse, such as high-resolution, dynamic, and time-of-flight PET reconstruction. The GPU approach runs more than 50 times faster than an equivalent CPU implementation while image quality and accuracy are virtually identical. This paper describes in details how the GPU can be used to accelerate the line projection operations, even when the lines-of-response have arbitrary endpoint locations and shift-varying resolution kernels are used. A quantitative evaluation is included to validate the correctness of this new approach.
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Affiliation(s)
- Guillem Pratx
- Department of Radiology, Molecular Imaging Program, Stanford University, Stanford, CA 94305 USA
| | - Garry Chinn
- Department of Radiology, Molecular Imaging Program, Stanford University, Stanford, CA 94305 USA
| | - Peter D. Olcott
- Department of Radiology, Molecular Imaging Program, Stanford University, Stanford, CA 94305 USA
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18282
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In patient dose reconstruction using a cine acquisition for dynamic arc radiation therapy. Med Biol Eng Comput 2009; 47:425-33. [DOI: 10.1007/s11517-009-0456-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2008] [Accepted: 01/04/2009] [Indexed: 10/21/2022]
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18283
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Travassos LV, Boechat MCB, Santos EN, Oliveira SRD, Silva MOD, Carvalho ACP. Avaliação das doses de radiação em uretrocistografia miccional de crianças. Radiol Bras 2009. [DOI: 10.1590/s0100-39842009000100006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
OBJETIVO: Analisar o produto dose-área, a dose de entrada na pele do paciente e as doses relativas à fluoroscopia e às radiografias em exames de cistouretrografia miccional em crianças. MATERIAIS E MÉTODOS: Foram avaliados os procedimentos em 37 pacientes, realizados por quatro médicos do serviço. As medições foram realizadas com um equipamento composto de uma câmara de ionização acoplada diretamente à saída do tubo de raios X e um eletrômetro (Diamentor) ligado diretamente ao computador, para a coleta dos dados. RESULTADOS: Foi observada alguma heterogeneidade na realização do procedimento, que não segue padrão de técnica radiográfica. São realizadas em média 11 radiografias por exame, usando tempo longo de fluoroscopia, com dose média final mais alta que a encontrada em referências da literatura. CONCLUSÃO: A adoção da técnica de alta quilovoltagem nas radiografias e o uso restrito da fluoroscopia podem proporcionar importante redução das doses durante a realização deste procedimento, porque o maior contribuinte para as altas doses verificadas foi a utilização da fluoroscopia.
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18284
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18285
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Ferreira BC, Lopes MC, Capela M. Evaluation of an Epson flatbed scanner to read Gafchromic EBT films for radiation dosimetry. Phys Med Biol 2009; 54:1073-85. [PMID: 19168937 DOI: 10.1088/0031-9155/54/4/017] [Citation(s) in RCA: 129] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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18286
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Pantos I, Patatoukas G, Katritsis DG, Efstathopoulos E. Patient radiation doses in interventional cardiology procedures. Curr Cardiol Rev 2009; 5:1-11. [PMID: 20066141 PMCID: PMC2803281 DOI: 10.2174/157340309787048059] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2008] [Revised: 08/01/2008] [Accepted: 08/01/2008] [Indexed: 11/22/2022] Open
Abstract
Interventional cardiology procedures result in substantial patient radiation doses due to prolonged fluoroscopy time and radiographic exposure. The procedures that are most frequently performed are coronary angiography, percutaneous coronary interventions, diagnostic electrophysiology studies and radiofrequency catheter ablation. Patient radiation dose in these procedures can be assessed either by measurements on a series of patients in real clinical practice or measurements using patient-equivalent phantoms. In this article we review the derived doses at non-pediatric patients from 72 relevant studies published during the last 22 years in international scientific literature. Published results indicate that patient radiation doses vary widely among the different interventional cardiology procedures but also among equivalent studies. Discrepancies of the derived results are patient-, procedure-, physician-, and fluoroscopic equipmentrelated. Nevertheless, interventional cardiology procedures can subject patients to considerable radiation doses. Efforts to minimize patient exposure should always be undertaken.
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Affiliation(s)
- Ioannis Pantos
- Department of Cardiology, Athens Euroclinic, Athens, Greece
- 2 Department of Radiology, Medical Physics Unit, University of Athens, Athens, Greece
| | - Georgios Patatoukas
- 2 Department of Radiology, Medical Physics Unit, University of Athens, Athens, Greece
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18287
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Guzzo TJ, Pierorazio PM, Schaeffer EM, Fishman EK, Allaf ME. The accuracy of multidetector computerized tomography for evaluating tumor thrombus in patients with renal cell carcinoma. J Urol 2008; 181:486-90; discussion 491. [PMID: 19100567 DOI: 10.1016/j.juro.2008.10.040] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2008] [Indexed: 11/19/2022]
Abstract
PURPOSE New advances in computerized tomography, including multidetector computerized tomography with 3-dimensional reformatting has recently called into question the absolute need for magnetic resonance imaging for evaluating renal cell carcinoma with suspected venous involvement. We assessed the accuracy of multidetector computerized tomography for predicting tumor thrombus and the level of venous involvement in patients with renal cell carcinoma. MATERIALS AND METHODS We retrospectively reviewed clinical and pathological features in 41 patients with renal cell carcinoma who underwent staging multidetector computerized tomography before surgery. Multidetector computerized tomography findings regarding the presence and level of tumor thrombus were compared to findings at surgery and at final pathological evaluation. All multidetector computerized tomography studies were read by a single radiologist (EKF) before surgery. RESULTS When excluding patients with segmental venous involvement only, the concordance rate between multidetector computerized tomography and pathological findings was 84%. Multidetector computerized tomography accurately predicted the level of tumor thrombus in 26 of 27 patients (96%). Four cases of negative multidetector computerized tomography findings were up staged to renal vein involvement based on pathological findings. All 4 patients had early distal thrombi that did not change operative management. CONCLUSIONS Multidetector computerized tomography with 3-dimensional mapping is an effective imaging modality for accurately characterizing the level of venous thrombus in patients with renal cell carcinoma. This modality effectively identified patients with clinically significant venous thrombus. Patients with renal cell carcinoma in whom multidetector computerized tomography fails to detect tumor thrombus are unlikely to have a tumor thrombus found at surgery that would change the surgical approach.
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Affiliation(s)
- Thomas J Guzzo
- The James Buchanan Brady Urologic Institute, The Johns Hopkins Medical Institutions, Baltimore, Maryland 21287, USA.
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18288
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Attanasi F, Belcari N, Del Guerra A, Enghardt W, Moehrs S, Parodi K, Rosso V, Vecchio S. Comparison of two dedicated ‘in beam’ PET systems via simultaneous imaging of12C-induced β+-activity. Phys Med Biol 2008; 54:N29-35. [DOI: 10.1088/0031-9155/54/2/n01] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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18289
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Dosimetric characteristics of an unshielded p-type Si diode: linearity, photon energy dependence and spatial resolution. Z Med Phys 2008; 18:301-6. [DOI: 10.1016/j.zemedi.2008.06.007] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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18290
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Gotanda R, Katsuda T, Gotanda T, Tabuchi A, Yatake H, Takeda Y. Dose distribution in pediatric CT head examination using a new phantom with radiochromic film. ACTA ACUST UNITED AC 2008; 31:339-44. [PMID: 19239061 DOI: 10.1007/bf03178604] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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18291
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Gemmel A, Hasch B, Ellerbrock M, Weyrather WK, Krämer M. Biological dose optimization with multiple ion fields. Phys Med Biol 2008; 53:6991-7012. [DOI: 10.1088/0031-9155/53/23/022] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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18292
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Lechel U, Becker C, Langenfeld-Jäger G, Brix G. Dose reduction by automatic exposure control in multidetector computed tomography: comparison between measurement and calculation. Eur Radiol 2008; 19:1027-34. [DOI: 10.1007/s00330-008-1204-6] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2008] [Accepted: 09/28/2008] [Indexed: 10/21/2022]
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18293
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Alfonso R, Andreo P, Capote R, Huq MS, Kilby W, Kjäll P, Mackie TR, Palmans H, Rosser K, Seuntjens J, Ullrich W, Vatnitsky S. A new formalism for reference dosimetry of small and nonstandard fields. Med Phys 2008; 35:5179-86. [DOI: 10.1118/1.3005481] [Citation(s) in RCA: 415] [Impact Index Per Article: 25.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
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18294
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Kaneshiro TL, Jeong EK, Morrell G, Parker DL, Lu ZR. Synthesis and evaluation of globular Gd-DOTA-monoamide conjugates with precisely controlled nanosizes for magnetic resonance angiography. Biomacromolecules 2008; 9:2742-8. [PMID: 18771313 PMCID: PMC2801583 DOI: 10.1021/bm800486c] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The purpose of this study was to design and prepare macromolecular contrast agents (CAs) with a precisely defined globular structure for MR angiography and tumor angiogenesis imaging. Generations 1 through 3 (Gd-DOTA-monoamide)-poly-L-lysine octasilsesquioxane dendrimers were prepared as nanoglobular MRI CAs. The nanoglobular Gd(III) chelates had a well-defined compact globular structure and high loading of Gd-DOTA-monoamide at their surface. The size of the G1, G2, and G3 nanoglobular MRI CAs was approximately 2.0, 2.4, and 3.2 nm, respectively. The T1 relaxivity of G1, G2, and G3 nanoglobular MRI CAs was approximately 6.4, 7.2, and 10.0 mM(-1) sec(-1) at 3T, respectively. The nanoglobular MRI CAs showed size-dependent contrast enhancement within the mouse vasculature, which gradually decayed to baseline after a 60 min session. The G3 nanoglobular CA resulted in more significant and prolonged vascular enhancement than the smaller nanoglobular agents at 0.03 mmol Gd/kg. The G3 agent also provided significant and prolonged contrast enhancement in the heart and vasculature at a dose as low as 0.01 mmol Gd/kg, 1/10th of the regular clinical dose. Significant enhancement was observed in tumor for all CAs. The nanoglobular CAs cleared via renal filtration and accumulated in the urinary bladder as shown in the dynamic MR images. The nanoglobular Gd(III) chelates are effective intravascular MRI CAs at substantially reduced doses. The nanoglobular MRI CAs are promising for further preclinical development for MR angiography and MR imaging of tumor angiogenesis.
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Affiliation(s)
- Todd Lyle Kaneshiro
- Department of Pharmaceutics and Pharmaceutical Chemistry, University of Utah, Salt Lake City, Utah 84108, USA
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18295
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Cukic M, Kalauzi A, Ilic T, Miskovic M, Ljubisavljevic M. The influence of coil-skull distance on transcranial magnetic stimulation motor-evoked responses. Exp Brain Res 2008; 192:53-60. [PMID: 18787813 DOI: 10.1007/s00221-008-1552-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2007] [Accepted: 08/14/2008] [Indexed: 11/30/2022]
Abstract
We have investigated the effects of changing the coil-to-skull distance on the motor-evoked responses (MEP) induced with two different magnetic stimulator coils (80 mm round and figure-of-eight coil) at rest and during voluntary muscle contraction. The changes in MEP latency, amplitude and silent period (SP) duration induced by stimulation directly upon the skull, and 1 cm away from the skull were analyzed by computing the probability density distribution (PDD) for the responses obtained from all subjects. This measure corresponds to the finite probability that the event occurs within a given area. Overall, the results were consistent with a distance-induced decrease in magnetic field strength. However, the increase in coil-to-skull distance induced a higher probability of longer latencies in active muscle when stimulating with either coil. Also, stimulating at a distance with the figure-of-eight coil increased the probability of a longer SP duration. The stimulation strength at the two distances was comparable because it was set based on the motor threshold obtained for each distance. Therefore, our results are not entirely compatible with the established exponential drop in magnetic field with increasing distance. Rather, they suggest that a more complex set of interactions occurs in the cortex. The results imply that distinct patterns of cortical network activation may exist related to the distance-induced alterations when the coil is moved away from the skull. Further studies are required to elucidate the precise nature of the distance-related interactions of the magnetic field with the cortex.
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Affiliation(s)
- M Cukic
- Department of Neurophysiology, Institute for Medical Research, Belgrade, PO Box 11121, Serbia
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18296
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Maughan RL, Van den Heuvel F, Orton CG. Within the next 10-15 years protons will likely replace photons as the most common type of radiation for curative radiotherapy. Med Phys 2008; 35:4285-8. [DOI: 10.1118/1.2955553] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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18297
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Abstract
Positron emission tomography (PET) is a tool for metabolic imaging that has been utilized since the earliest days of nuclear medicine. A key component of such imaging systems is the detector modules--an area of research and development with a long, rich history. Development of detectors for PET has often seen the migration of technologies, originally developed for high energy physics experiments, into prototype PET detectors. Of the many areas explored, some detector designs go on to be incorporated into prototype scanner systems and a few of these may go on to be seen in commercial scanners. There has been a steady, often very diverse development of prototype detectors, and the pace has accelerated with the increased use of PET in clinical studies (currently driven by PET/CT scanners) and the rapid proliferation of pre-clinical PET scanners for academic and commercial research applications. Most of these efforts are focused on scintillator-based detectors, although various alternatives continue to be considered. For example, wire chambers have been investigated many times over the years and more recently various solid-state devices have appeared in PET detector designs for very high spatial resolution applications. But even with scintillators, there have been a wide variety of designs and solutions investigated as developers search for solutions that offer very high spatial resolution, fast timing, high sensitivity and are yet cost effective. In this review, we will explore some of the recent developments in the quest for better PET detector technology.
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Affiliation(s)
- Tom K Lewellen
- Division of Nuclear Medicine, University of Washington Medical Center, 222 Old Fisheries Science Center, Seattle, Washington 98195, USA.
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18298
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Abstract
Despite technical advances in many areas of diagnostic radiology, the detection and imaging of human cancer remains poor. A meaningful impact on cancer screening, staging, and treatment is unlikely to occur until the tumor-to-background ratio improves by three to four orders of magnitude (ie, 10(3)- to 10(4)-fold), which in turn will require proportional improvements in sensitivity and contrast agent targeting. This review analyzes the physics and chemistry of cancer imaging and highlights the fundamental principles underlying the detection of malignant cells within a background of normal cells. The use of various contrast agents and radiotracers for cancer imaging is reviewed, as are the current limitations of ultrasound, x-ray imaging, magnetic resonance imaging (MRI), single-photon emission computed tomography, positron emission tomography (PET), and optical imaging. Innovative technologies are emerging that hold great promise for patients, such as positron emission mammography of the breast and spectroscopy-enhanced colonoscopy for cancer screening, hyperpolarization MRI and time-of-flight PET for staging, and ion beam-induced PET scanning and near-infrared fluorescence-guided surgery for cancer treatment. This review explores these emerging technologies and considers their potential impact on clinical care. Finally, those cancers that are currently difficult to image and quantify, such as ovarian cancer and acute leukemia, are discussed.
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Affiliation(s)
- John V Frangioni
- Beth Israel Deaconess Medical Center, 330 Brookline Ave, Rm SL-B05, Boston, MA 02215, USA.
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18299
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Lo SY, Yen G, Thanh M, Chiu SL. Demonstration of Group Healing Using Infrared Imaging. Med Acupunct 2008. [DOI: 10.1089/acu.2008.0617] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Shui-Yin Lo
- Quantum Health Research Institute, Pasadena, CA
| | - Grace Yen
- Quantum Health Research Institute, Pasadena, CA
| | - Minh Thanh
- Quantum Health Research Institute, Pasadena, CA
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18300
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Lansley SP, Betzel GT, Baluti F, Lydon J, Reinisch L. Suitability of synthetic diamond films for x-ray dosimetry applications. ACTA ACUST UNITED AC 2008. [DOI: 10.1109/commad.2008.4802086] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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