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[PMID]:28457786
[Au] Autor:Pacilio M; Cassano B; Pellegrini R; Di Castro E; Zorz A; De Vincentis G; Ventroni G; Mango L; Giancola S; Ferrari M; Cremonesi M; Bianchi C; Virotta G; Carbonini C; Cesana P; Fulcheri C; Reggioli V; Ricci A; Trevisiol E; Anglesio S; Pani R
[Ad] Endereço:Department of Medical Physics, Azienda Ospedaliera Universitaria Policlinico Umberto I, Viale del Policlinico 155, 00161 Rome, Italy. Electronic address: M.Pacilio@policlinicoumberto1.it.
[Ti] Título:Gamma camera calibrations for the Italian multicentre study for lesion dosimetry in Ra therapy of bone metastases.
[So] Source:Phys Med;41:117-123, 2017 Sep.
[Is] ISSN:1724-191X
[Cp] País de publicação:Italy
[La] Idioma:eng
[Ab] Resumo:PURPOSE: The aim was to calibrate gamma cameras in the framework of the Italian multicentre study for lesion dosimetry in Ra therapy of bone metastases. Equipments of several manufacturers and different models were used. METHODS: Eleven gamma cameras (3/8- and 5/8-inch crystal) were used, acquiring planar static images with double-peak (82 and 154keV, 20% wide) and MEGP collimator. The sensitivity was measured in air, varying source-detector distance and source size. Transmission curves were measured, calculating the parameters used for attenuation/scatter correction with the pseudo-extrapolation number method, and assessing their variations with the source size. RESULTS: Values of the calibration factor (geometric mean of both detector sensitivities) ranged from 41.1 to 113.9cps/MBq. For the smallest source (diameter of 3.5cm), the calibration factor decrease ranged from -30% to -4%, highlighting the importance of partial volume effects according to the equipment involved. The sensitivity variation with the source-detector distance, with respect to the 15cm-value, reached 10% (in absolute value) in the range 5-30cm, but fixing the distance between the two heads, the calibration factor variation with the distance from the midline was within 3.6%. Appreciable variation of the transmission curves with the source size were observed, examining the results obtained with six gamma cameras. CONCLUSION: Assessments of sensitivity and transmission curve variations with source size should be regularly implemented in calibration procedures. The results of this study represent a useful compendium to check the obtained calibrations for dosimetric purposes.
[Mh] Termos MeSH primário: Neoplasias Ósseas/radioterapia
Câmaras gama
Radiometria/normas
[Mh] Termos MeSH secundário: Calibragem
Seres Humanos
Itália
[Pt] Tipo de publicação:JOURNAL ARTICLE; MULTICENTER STUDY
[Em] Mês de entrada:1801
[Cu] Atualização por classe:180118
[Lr] Data última revisão:
180118
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170502
[St] Status:MEDLINE


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[PMID]:29267305
[Au] Autor:Yeh DM; Chen CY; Tang JF; Pan LK
[Ad] Endereço:Department of Diagnostic Radiology, Chung Shan Medical University Hospital, Taichung, Taiwan, ROC.
[Ti] Título:A quantitative evaluation of multiple biokinetic models using an assembled water phantom: A feasibility study.
[So] Source:PLoS One;12(12):e0189244, 2017.
[Is] ISSN:1932-6203
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:This study examined the feasibility of quantitatively evaluating multiple biokinetic models and established the validity of the different compartment models using an assembled water phantom. Most commercialized phantoms are made to survey the imaging system since this is essential to increase the diagnostic accuracy for quality assurance. In contrast, few customized phantoms are specifically made to represent multi-compartment biokinetic models. This is because the complicated calculations as defined to solve the biokinetic models and the time-consuming verifications of the obtained solutions are impeded greatly the progress over the past decade. Nevertheless, in this work, five biokinetic models were separately defined by five groups of simultaneous differential equations to obtain the time-dependent radioactive concentration changes inside the water phantom. The water phantom was assembled by seven acrylic boxes in four different sizes, and the boxes were linked to varying combinations of hoses to signify the multiple biokinetic models from the biomedical perspective. The boxes that were connected by hoses were then regarded as a closed water loop with only one infusion and drain. 129.1±24.2 MBq of Tc-99m labeled methylene diphosphonate (MDP) solution was thoroughly infused into the water boxes before gamma scanning; then the water was replaced with de-ionized water to simulate the biological removal rate among the boxes. The water was driven by an automatic infusion pump at 6.7 c.c./min, while the biological half-life of the four different-sized boxes (64, 144, 252, and 612 c.c.) was 4.8, 10.7, 18.8, and 45.5 min, respectively. The five models of derived time-dependent concentrations for the boxes were estimated either by a self-developed program run in MATLAB or by scanning via a gamma camera facility. Either agreement or disagreement between the practical scanning and the theoretical prediction in five models was thoroughly discussed. The derived biokinetic model represented the metabolic mechanism in the human body and helped to solidify the internal circulatory system into concert with numerical verification.
[Mh] Termos MeSH primário: Difosfonatos/farmacocinética
Modelos Teóricos
Imagens de Fantasmas
[Mh] Termos MeSH secundário: Estudos de Viabilidade
Câmaras gama
Meia-Vida
Água
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Diphosphonates); 059QF0KO0R (Water); 73OS0QIN3O (methylene diphosphonate)
[Em] Mês de entrada:1801
[Cu] Atualização por classe:180116
[Lr] Data última revisão:
180116
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:171222
[St] Status:MEDLINE
[do] DOI:10.1371/journal.pone.0189244


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[PMID]:28816148
[Au] Autor:Xie Y; Bentefour EH; Janssens G; Smeets J; Vander Stappen F; Hotoiu L; Yin L; Dolney D; Avery S; O'Grady F; Prieels D; McDonough J; Solberg TD; Lustig RA; Lin A; Teo BK
[Ad] Endereço:Department of Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania.
[Ti] Título:Prompt Gamma Imaging for In Vivo Range Verification of Pencil Beam Scanning Proton Therapy.
[So] Source:Int J Radiat Oncol Biol Phys;99(1):210-218, 2017 Sep 01.
[Is] ISSN:1879-355X
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:PURPOSE: To report the first clinical results and value assessment of prompt gamma imaging for in vivo proton range verification in pencil beam scanning mode. METHODS AND MATERIALS: A stand-alone, trolley-mounted, prototype prompt gamma camera utilizing a knife-edge slit collimator design was used to record the prompt gamma signal emitted along the proton tracks during delivery of proton therapy for a brain cancer patient. The recorded prompt gamma depth detection profiles of individual pencil beam spots were compared with the expected profiles simulated from the treatment plan. RESULTS: In 6 treatment fractions recorded over 3 weeks, the mean (± standard deviation) range shifts aggregated over all spots in 9 energy layers were -0.8 ± 1.3 mm for the lateral field, 1.7 ± 0.7 mm for the right-superior-oblique field, and -0.4 ± 0.9 mm for the vertex field. CONCLUSIONS: This study demonstrates the feasibility and illustrates the distinctive benefits of prompt gamma imaging in pencil beam scanning treatment mode. Accuracy in range verification was found in this first clinical case to be better than the range uncertainty margin applied in the treatment plan. These first results lay the foundation for additional work toward tighter integration of the system for in vivo proton range verification and quantification of range uncertainties.
[Mh] Termos MeSH primário: Neoplasias Encefálicas/diagnóstico por imagem
Neoplasias Encefálicas/radioterapia
Câmaras gama
Terapia com Prótons/métodos
Cintilografia/métodos
[Mh] Termos MeSH secundário: Fracionamento de Dose
Desenho de Equipamento
Estudos de Viabilidade
Seres Humanos
Cintilografia/instrumentação
Planejamento da Radioterapia Assistida por Computador
[Pt] Tipo de publicação:CASE REPORTS; JOURNAL ARTICLE
[Em] Mês de entrada:1708
[Cu] Atualização por classe:170821
[Lr] Data última revisão:
170821
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170818
[St] Status:MEDLINE


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[PMID]:28275975
[Au] Autor:Moslemi V; Ashoor M
[Ad] Endereço:Nuclear Science and Technology Research Institute, AEOI, P.O. Box: 113653486, Tehran, Iran. vmoslemi@gmail.com.
[Ti] Título:Design and performance evaluation of a new high energy parallel hole collimator for radioiodine planar imaging by gamma cameras: Monte Carlo simulation study.
[So] Source:Ann Nucl Med;31(4):324-334, 2017 May.
[Is] ISSN:1864-6433
[Cp] País de publicação:Japan
[La] Idioma:eng
[Ab] Resumo:OBJECTIVE: In addition to the trade-off between resolution and sensitivity which is a common problem among all types of parallel hole collimators (PCs), obtained images by high energy PCs (HEPCs) suffer from hole-pattern artifact (HPA) due to further septa thickness. In this study, a new design on the collimator has been proposed to improve the trade-off between resolution and sensitivity and to eliminate the HPA. METHODS: A novel PC, namely high energy extended PC (HEEPC), is proposed and is compared to HEPCs. In the new PC, trapezoidal denticles were added upon the septa in the detector side. The performance of the HEEPCs were evaluated and compared to that of HEPCs using a Monte Carlo-N-particle version5 (MCNP5) simulation. The point spread functions (PSF) of HEPCs and HEEPCs were obtained as well as the various parameters such as resolution, sensitivity, scattering, and penetration ratios, and the HPA of the collimators was assessed. Furthermore, a Picker phantom study was performed to examine the effects of the collimators on the quality of planar images. RESULTS: It was found that the HEEPC with an identical resolution to that of HEPC increased sensitivity by 34.7%, and it improved the trade-off between resolution and sensitivity as well as to eliminate the HPA. In the picker phantom study, the HEEPC indicated the hot and cold lesions with the higher contrast, lower noise, and higher contrast to noise ratio (CNR). CONCLUSION: Since the HEEPCs modify the shaping of PSFs, they are able to improve the trade-off between the resolution and sensitivity; consequently, planar images can be achieved with higher contrast resolutions. Furthermore, because the HEEPC reduce the HPA and produce images with a higher CNR, compared to HEPCs, the obtained images by HEEPCs have a higher quality, which can help physicians to provide better diagnosis.
[Mh] Termos MeSH primário: Câmaras gama
Cintilografia/instrumentação
[Mh] Termos MeSH secundário: Artefatos
Simulação por Computador
Desenho de Equipamento
Método de Monte Carlo
Imagens de Fantasmas
Fótons
Espalhamento de Radiação
[Pt] Tipo de publicação:EVALUATION STUDIES; JOURNAL ARTICLE
[Em] Mês de entrada:1706
[Cu] Atualização por classe:170612
[Lr] Data última revisão:
170612
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170310
[St] Status:MEDLINE
[do] DOI:10.1007/s12149-017-1160-9


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[PMID]:28216330
[Au] Autor:Sánchez-Jiménez J; López-Montes A; Núñez-Martínez L; Villa-Abaunza A; Fraile LM; Sánchez-Tembleque V; Udías JM
[Ad] Endereço:Servicio de Radiofísica y Protección Radiológica, Hospital Universitario de Burgos, Avenida Islas Baleares N°3, E-09006 Burgos, Spain. Electronic address: javiersjim@gmail.com.
[Ti] Título:Ra-dichloride spectrometric characterization: Searching for the presence of long-lived isotopes with radiological protection implications.
[So] Source:Phys Med;35:97-101, 2017 Mar.
[Is] ISSN:1724-191X
[Cp] País de publicação:Italy
[La] Idioma:eng
[Ab] Resumo:Ra-dichloride was approved with the commercial name of Xofigo in 2014 for treatment of metastatic castration-resistant prostate cancer. Ra is obtained by neutron irradiation of Ra yielding Ac, which decays to Th and Fr, both decaying to Ra. Since Ra is predominantly (95.3%) an alpha emitter with a 11.42days long half-life, the radiopharmaceutical, its remnants, the patient, and waste material can be managed and disposed with low radiation protection requirements. Ac is a long-lived (T =21.77years) beta emitter that demands strong radiation protection measures. In particular waste disposal has to follow the International Atomic Energy Agency (IAEA) and European Commission (EC) regulations. Since Ac is involved in the production of Ra, an impurity analysis of each batch is required after production. Due to time restrictions, the manufacturer's detection limit (<0.001%) exceeds the one required to assure that Ac concentrations are below direct disposal levels. To improve the detection limit, long-term accurate spectroscopy is required. Alpha and gamma spectroscopy measurements were carried out at the Complutense University Nuclear Physics Laboratory. After twelve months follow up of a sample, Ac concentration was found to be smaller than 10 . This allows for direct waste disposal and no additional radiation protection restrictions than those required for Ra. The presence of contamination by other radioisotopes was also ruled out by this experiment. Specifically Ra, involved in Ra production as the original parent and with a very long-lived (T =1577years) alpha emitter, was also below the experimental detection limit.
[Mh] Termos MeSH primário: Rádio (Elemento)/química
[Mh] Termos MeSH secundário: Câmaras gama
Seres Humanos
Saúde do Trabalhador
Segurança do Paciente
Proteção Radiológica/métodos
Resíduos Radioativos
Radioisótopos/química
Radiometria/métodos
Análise Espectral
Fatores de Tempo
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Radioactive Waste); 0 (Radioisotopes); 0 (radium Ra 223 dichloride); W90AYD6R3Q (Radium)
[Em] Mês de entrada:1704
[Cu] Atualização por classe:170410
[Lr] Data última revisão:
170410
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170221
[St] Status:MEDLINE


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[PMID]:28192280
[Au] Autor:Morozov A; Alves F; Marcos J; Martins R; Pereira L; Solovov V; Chepel V
[Ad] Endereço:LIP-Coimbra, Department of Physics, University of Coimbra, Coimbra, Portugal. Department of Physics, University of Coimbra, Coimbra, Portugal.
[Ti] Título:Iterative reconstruction of SiPM light response functions in a square-shaped compact gamma camera.
[So] Source:Phys Med Biol;62(9):3619-3638, 2017 May 07.
[Is] ISSN:1361-6560
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:Compact gamma cameras with a square-shaped monolithic scintillator crystal and an array of silicon photomultipliers (SiPMs) are actively being developed for applications in areas such as small animal imaging, cancer diagnostics and radiotracer guided surgery. Statistical methods of position reconstruction, which are potentially superior to the traditional centroid method, require accurate knowledge of the spatial response of each photomultiplier. Using both Monte Carlo simulations and experimental data obtained with a camera prototype, we show that the spatial response of all photomultipliers (light response functions) can be parameterized with axially symmetric functions obtained iteratively from flood field irradiation data. The study was performed with a camera prototype equipped with a 30 × 30 × 2 mm LYSO crystal and an 8 × 8 array of SiPMs for 140 keV gamma rays. The simulations demonstrate that the images, reconstructed with the maximum likelihood method using the response obtained with the iterative approach, exhibit only minor distortions: the average difference between the reconstructed and the true positions in X and Y directions does not exceed 0.2 mm in the central area of 22 × 22 mm and 0.4 mm at the periphery of the camera. A similar level of image distortions is shown experimentally with the camera prototype.
[Mh] Termos MeSH primário: Câmaras gama
Fótons
Cintilografia/métodos
[Mh] Termos MeSH secundário: Raios gama
Funções Verossimilhança
Método de Monte Carlo
Cintilografia/instrumentação
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Em] Mês de entrada:1709
[Cu] Atualização por classe:170926
[Lr] Data última revisão:
170926
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170214
[St] Status:MEDLINE
[do] DOI:10.1088/1361-6560/aa6029


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[PMID]:28192245
[Au] Autor:Mehrabibahar M; Mousavi Z; Sadeghi R; Layegh P; Nouri M; Asadi M
[Ad] Endereço:Surgical Oncology Research Center, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.
[Ti] Título:Feasibility and safety of minimally invasive radioguided parathyroidectomy using very low intraoperative dose of Tc-99m MIBI.
[So] Source:Int J Surg;39:229-233, 2017 Mar.
[Is] ISSN:1743-9159
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:BACKGROUND: Surgical resection of the abnormal parathyroid glands is the only curative treatment for primary hyperparathyroidism (PHPT). Radioguided parathyroidectomy with technetium-99m (TC-99m) sestamibi has been successfully used in patients with PHPT. This study was designed to evaluate the results of a series of patients with PHPT who underwent minimally invasive radioguided parathyroidectomy (MIRP) using very low dose (1 mCi) of TC-99m sestamibi (MIBI) without application of intraoperative parathyroid hormone (PTH) assay or frozen section analysis. METHODS: Eighty-seven patients with PHPT were prospectively studied from November 2012 to January 2015. Following neck ultrasound (US) and MIBI scan concordant for single gland disease, patients underwent MIRP using a handheld gamma probe. The technique involved injecting of 1 mCi MIBI in the operative room before the beginning of the intervention. All patients were followed up for a minimum of 6 months postoperatively. RESULTS: MIRP was successfully performed in 86 out of 87 patients (98.85%). The Gamma probe was particularly useful in detection of ectopic parathyroid adenomas in upper mediastinum. Mean operative time was 23.95 ± 7.982 min and mean hospital stay was 1.44 ± 0.604 days. No major surgical complications were recorded. CONCLUSIONS: The MIRP technique using very low dose (1 mCi) of Tc-99m MIBI without intraoperative PTH assay and frozen section analysis resulted in excellent cure rate for PHPT. This technique involves a radiation exposure to patients and surgical staffs 20 times lower than conventional MIRP using 20 mCi Tc-99m MIBI. Besides, patients with PHPT due to ectopic parathyroid adenoma may especially benefit from MIRP.
[Mh] Termos MeSH primário: Hiperparatireoidismo Primário/diagnóstico por imagem
Hiperparatireoidismo Primário/cirurgia
Paratireoidectomia/métodos
[Mh] Termos MeSH secundário: Adenoma/diagnóstico por imagem
Adenoma/cirurgia
Adulto
Idoso
Estudos de Viabilidade
Feminino
Câmaras gama
Seres Humanos
Tempo de Internação/estatística & dados numéricos
Masculino
Meia-Idade
Procedimentos Cirúrgicos Minimamente Invasivos/efeitos adversos
Procedimentos Cirúrgicos Minimamente Invasivos/métodos
Duração da Cirurgia
Hormônio Paratireóideo/sangue
Neoplasias das Paratireoides/diagnóstico por imagem
Neoplasias das Paratireoides/cirurgia
Paratireoidectomia/efeitos adversos
Período Pós-Operatório
Dose de Radiação
Radiologia Intervencionista/métodos
Cintilografia/instrumentação
Cintilografia/métodos
Compostos Radiofarmacêuticos/administração & dosagem
Segurança
Tecnécio Tc 99m Sestamibi/administração & dosagem
[Pt] Tipo de publicação:JOURNAL ARTICLE; OBSERVATIONAL STUDY
[Nm] Nome de substância:
0 (Parathyroid Hormone); 0 (Radiopharmaceuticals); 971Z4W1S09 (Technetium Tc 99m Sestamibi)
[Em] Mês de entrada:1705
[Cu] Atualização por classe:170509
[Lr] Data última revisão:
170509
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170214
[St] Status:MEDLINE


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[PMID]:28072581
[Au] Autor:Barquero R; Garcia HP; Incio MG; Minguez P; Cardenas A; Martínez D; Lassmann M
[Ad] Endereço:Medical Physics, Hospital Clínico Universitario de Valladolid, Avda. Ramón y Cajal 3, 47005 Valladolid, Spain.
[Ti] Título:I activity quantification of gamma camera planar images.
[So] Source:Phys Med Biol;62(3):909-926, 2017 Feb 07.
[Is] ISSN:1361-6560
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:A procedure to estimate the activity in target tissues in patients during the therapeutic administration of I radiopharmaceutical treatment for thyroid conditions (hyperthyroidism and differentiated thyroid cancer) using a gamma camera (GC) with a high energy (HE) collimator, is proposed. Planar images are acquired for lesions of different sizes r, and at different distances d, in two HE GC systems. Defining a region of interest (ROI) on the image of size r, total counts n are measured. Sensitivity S (cps MBq ) in each acquisition is estimated as the product of the geometric G and the intrinsic efficiency η . The mean fluence of 364 keV photons arriving at the ROI per disintegration G, is calculated with the MCNPX code, simulating the entire GC and the HE collimator. Intrinsic efficiency η is estimated from a calibration measurement of a plane reference source of I in air. Values of G and S for two GC systems-Philips Skylight and Siemens e-cam-are calculated. The total range of possible sensitivity values in thyroidal imaging in the e-cam and skylight GC measure from 7 cps MBq to 35 cps MBq , and from 6 cps MBq to 29 cps MBq , respectively. These sensitivity values have been verified with the SIMIND code, with good agreement between them. The results have been validated with experimental measurements in air, and in a medium with scatter and attenuation. The counts in the ROI can be produced by direct, scatter and penetration photons. The fluence value for direct photons is constant for any r and d values, but scatter and penetration photons show different values related to specific r and d values, resulting in the large sensitivity differences found. The sensitivity in thyroidal GC planar imaging is strongly dependent on uptake size, and distance from the GC. An individual value for the acquisition sensitivity of each lesion can significantly alleviate the level of uncertainty in the measurement of thyroid uptake activity for each patient.
[Mh] Termos MeSH primário: Câmaras gama
Radioisótopos do Iodo/uso terapêutico
Tomografia por Emissão de Pósitrons/métodos
Dose de Radiação
Compostos Radiofarmacêuticos/uso terapêutico
Radioterapia Guiada por Imagem/métodos
[Mh] Termos MeSH secundário: Seres Humanos
Fótons
Tomografia por Emissão de Pósitrons/instrumentação
Radioterapia Guiada por Imagem/instrumentação
Neoplasias da Glândula Tireoide/diagnóstico por imagem
Neoplasias da Glândula Tireoide/radioterapia
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Iodine Radioisotopes); 0 (Radiopharmaceuticals)
[Em] Mês de entrada:1710
[Cu] Atualização por classe:171019
[Lr] Data última revisão:
171019
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170111
[St] Status:MEDLINE
[do] DOI:10.1088/1361-6560/62/3/909


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[PMID]:28044322
[Au] Autor:van der Velden S; Beijst C; Viergever MA; de Jong HW
[Ad] Endereço:Radiology and Nuclear Medicine, UMC Utrecht, 85500, 3508 GA, Utrecht, Netherlands.
[Ti] Título:Simultaneous fluoroscopic and nuclear imaging: impact of collimator choice on nuclear image quality.
[So] Source:Med Phys;44(1):249-261, 2017 Jan.
[Is] ISSN:2473-4209
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:PURPOSE: X-ray-guided oncological interventions could benefit from the availability of simultaneously acquired nuclear images during the procedure. To this end, a real-time, hybrid fluoroscopic and nuclear imaging device, consisting of an X-ray c-arm combined with gamma imaging capability, is currently being developed (Beijst C, Elschot M, Viergever MA, de Jong HW. Radiol. 2015;278:232-238). The setup comprises four gamma cameras placed adjacent to the X-ray tube. The four camera views are used to reconstruct an intermediate three-dimensional image, which is subsequently converted to a virtual nuclear projection image that overlaps with the X-ray image. The purpose of the present simulation study is to evaluate the impact of gamma camera collimator choice (parallel hole versus pinhole) on the quality of the virtual nuclear image. METHODS: Simulation studies were performed with a digital image quality phantom including realistic noise and resolution effects, with a dynamic frame acquisition time of 1 s and a total activity of 150 MBq. Projections were simulated for 3, 5, and 7 mm pinholes and for three parallel hole collimators (low-energy all-purpose (LEAP), low-energy high-resolution (LEHR) and low-energy ultra-high-resolution (LEUHR)). Intermediate reconstruction was performed with maximum likelihood expectation-maximization (MLEM) with point spread function (PSF) modeling. In the virtual projection derived therefrom, contrast, noise level, and detectability were determined and compared with the ideal projection, that is, as if a gamma camera were located at the position of the X-ray detector. Furthermore, image deformations and spatial resolution were quantified. Additionally, simultaneous fluoroscopic and nuclear images of a sphere phantom were acquired with a physical prototype system and compared with the simulations. RESULTS: For small hot spots, contrast is comparable for all simulated collimators. Noise levels are, however, 3 to 8 times higher in pinhole geometries than in parallel hole geometries. This results in higher contrast-to-noise ratios for parallel hole geometries. Smaller spheres can thus be detected with parallel hole collimators than with pinhole collimators (17 mm vs 28 mm). Pinhole geometries show larger image deformations than parallel hole geometries. Spatial resolution varied between 1.25 cm for the 3 mm pinhole and 4 cm for the LEAP collimator. The simulation method was successfully validated by the experiments with the physical prototype. CONCLUSION: A real-time hybrid fluoroscopic and nuclear imaging device is currently being developed. Image quality of nuclear images obtained with different collimators was compared in terms of contrast, noise, and detectability. Parallel hole collimators showed lower noise and better detectability than pinhole collimators.
[Mh] Termos MeSH primário: Fluoroscopia/métodos
Imagem Multimodal/métodos
Cintilografia/métodos
[Mh] Termos MeSH secundário: Artefatos
Fluoroscopia/instrumentação
Câmaras gama
Imagem Multimodal/instrumentação
Imagens de Fantasmas
Controle de Qualidade
Cintilografia/instrumentação
Razão Sinal-Ruído
Fatores de Tempo
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Em] Mês de entrada:1703
[Cu] Atualização por classe:170315
[Lr] Data última revisão:
170315
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170104
[St] Status:MEDLINE
[do] DOI:10.1002/mp.12010


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[PMID]:28033510
[Au] Autor:Ghosh D; Michalopoulos NV; Davidson T; Wickham F; Williams NR; Keshtgar MR
[Ad] Endereço:Department of Surgery, University College London, Royal Free London NHS Foundation Trust, UK.
[Ti] Título:Sentinel node detection in early breast cancer with intraoperative portable gamma camera: UK experience.
[So] Source:Breast;32:53-59, 2017 Apr.
[Is] ISSN:1532-3080
[Cp] País de publicação:Netherlands
[La] Idioma:eng
[Ab] Resumo:PURPOSE: Access to nuclear medicine department for sentinel node imaging remains an issue in number of hospitals in the UK and many parts of the world. Sentinella is a portable imaging camera used intra-operatively to produce real time visual localisation of sentinel lymph nodes. METHODS: Sentinella was tested in a controlled laboratory environment at our centre and we report our experience on the first use of this technology from UK. Moreover, preoperative scintigrams of the axilla were obtained in 144 patients undergoing sentinel node biopsy using conventional gamma camera. Sentinella scans were done intra-operatively to correlate with the pre-operative scintigram and to determine presence of any residual hot node after the axilla was deemed to be clear based on the silence of the hand held gamma probe. RESULTS: Sentinella detected significantly more nodes compared with CGC (p < 0.0001). Sentinella picked up extra nodes in 5/144 cases after the axilla was found silent using hand held gamma probe. In 2/144 cases, extra nodes detected by Sentinella confirmed presence of tumour cells that led to a complete axillary clearance. CONCLUSIONS: Sentinella is a reliable technique for intra-operative localisation of radioactive nodes. It provides increased nodal visualisation rates compared to static scintigram imaging and proves to be an important tool for harvesting all hot sentinel nodes. This portable gamma camera can definitely replace the use of conventional lymphoscintigrams saving time and money both for patients and the health system.
[Mh] Termos MeSH primário: Neoplasias da Mama/diagnóstico por imagem
Câmaras gama
Linfonodos/diagnóstico por imagem
Cintilografia/instrumentação
Linfonodo Sentinela/diagnóstico por imagem
[Mh] Termos MeSH secundário: Idoso
Axila
Neoplasias da Mama/patologia
Estudos de Viabilidade
Feminino
Seres Humanos
Cuidados Intraoperatórios/instrumentação
Linfonodos/patologia
Metástase Linfática
Meia-Idade
Linfonodo Sentinela/patologia
Reino Unido
[Pt] Tipo de publicação:EVALUATION STUDIES; JOURNAL ARTICLE
[Em] Mês de entrada:1703
[Cu] Atualização por classe:170320
[Lr] Data última revisão:
170320
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:161230
[St] Status:MEDLINE



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