terça-feira, 28 de fevereiro de 2012

XVIICBFM - 08 a 11 de agosto, Salvador - BA

Clique na imagem e será redirecionado para o site oficial do Congresso

Prezados(as) colegas, entre 8 e 11 de agosto de 2012, a Associação Brasileira de Física Médica realizará no Centro de Convenções do Bahia Othon Palace Hotel em Salvador, Bahia, a décima sétima edição de seu congresso.
As Comissões Organizadora e Científica estão trabalhando arduamente para preparar uma programação científica atual e em sintonia com as necessidades dos profissionais da área, tendo como palestrantes renomados especialistas do país e do exterior visando discutir os avanços científicos da física médica.
O Congresso da ABFM também é um momento de confraternização e troca de experiências, importante para o fortalecimento e o crescimento da nossa especialidade.
Estima-se a participação de 700 profissionais oriundos dos mais diferentes estados brasileiros, entre físicos médicos, pesquisadores, aprimorandos, estudantes, biomédicos, tecnólogos e outros profissionais da saúde.
O sucesso deste congresso depende de seu apoio e participação.

Contamos com sua presença!

Edmario Antonio Guimarães Costa
Presidente do XVII CBFM

fonte: site ABFM

sexta-feira, 24 de fevereiro de 2012

Integrando diferentes metodologias em MR

Gostei do artigo abaixo pelo fato de duas tecnicas bem distintas terem sido utilizadas no mesmo estudo. E' importante que profissionais da area de MR tenham um visao ampla das tecnicas disponiveis e possuam um pelo menos um conhecimento basal das mesmas, mesmo que esta tarefa nao seja muito facil.

Proton magnetic resonance spectroscopy of the motor cortex in cervical myelopathy:
Alterations in motor function in cervical myelopathy secondary to degenerative disease may be due to local effects of spinal compression or distal effects related to cortical reorganization. This prospective study characterizes differences in metabolite levels in the motor cortex, specifically N-acetylaspartate, creatine, choline, myo-inositol and glutamate plus glutamine, due to alterations in cortical function in patients with reversible spinal cord compression compared with healthy controls. We hypothesized that N-acetylaspartate/creatine levels would be decreased in the motor cortex of patients with cervical myelopathy due to reduced neuronal integrity/function and myo-inositol/creatine levels would be increased due to reactive gliosis. Twenty-four patients with cervical myelopathy and 11 healthy controls underwent proton-magnetic resonance spectroscopy on a 3.0 Tesla Siemens Magnetom Tim Trio MRI. Areas of activation from functional magnetic resonance imaging scans of a finger-tapping paradigm were used to localize a voxel on the side of greater motor deficit in the myelopathy group (n = 10 on right side and n = 14 on left side of the brain) and on each side of the motor cortex in controls. Neurological function was measured with the Neck Disability Index, modified Japanese Orthopaedic Association and American Spinal Injury Association questionnaires. Metabolite levels were measured relative to total creatine within the voxel of interest. No metabolite differences were detected between the right side and left side of the motor cortex in controls. The myelopathy group had significantly decreased neurological function compared with the control group (Neck Disability Index: P < 0.001 and modified Japanese Orthopaedic Association: P < 0.001). There was a significant decrease in the N-acetylaspartate/creatine metabolite ratio in the motor cortex of the myelopathy group (1.21 ± 0.07) compared with the right (1.37 ± 0.03; P = 0.01) and left (1.38 ± 0.03; P = 0.007) motor cortex in controls suggesting neuronal damage or dysfunction distal to the lesion in the spine. No difference was observed in levels of myo-inositol/creatine. Thus, cortical levels of N-acetylaspartate/creatine may be a meaningful biomarker in cervical myelopathy, indicative of neuronal damage or dysfunction.

PS: Perdao pelas acentuacoes (!) - problemas tecnicos com o computador.

quarta-feira, 22 de fevereiro de 2012

Evitando doses desnecessárias em pacientes durante a transição da radiologia analógica para a digital

IAEA Radiation Protection of Patients 
 Em um documento recente (outubro 2011), a IAEA, publicou algumas ações e explicações que contribuirão para a conscientização da utilização das novas tecnologias que estão no mercado. Esse documento esclarece bastante sobre as relações de exposição e formação de imagens das técnicas analógicas e digitais.

Tc-99m production feasible with cyclotrons

February 22, 2012 -- A team of Canadian researchers has successfully produced the radioisotope technetium-99m (Tc-99m) on cyclotrons already available in Ontario and British Columbia.
The process, achieved on a cyclotron from GE Healthcare, would allow hospitals and clinics with existing cyclotrons to make the isotope that traditionally has only been available from nuclear reactors.
The core of the technology includes preparing solid targets of molybdenum-100 and placing them in an automated system for irradiation with the cyclotron. The team developed these tools along with chemistry that isolates and purifies the Tc-99m.
The researchers come from TRIUMF, BC Cancer Agency, Lawson Health Research Institute, and the Centre for Probe Development and Commercialization. They made the announcement on February 20 at the annual meeting of the American Association for the Advancement of Science in Vancouver.
Paul Schaffer, head of TRIUMF's nuclear medicine division, said that the ability to make medical isotopes in hospitals, rather than nuclear reactors, is a "major milestone for diagnostic imaging for patients in Canada and around the world."
The advance is particularly important for nuclear medicine procedures that use Tc-99m to image disease in the heart, bones, and throughout the body.

fonte: Auntminnie

DTI-MRI shows brain differences in infants who develop autism

 Image of white-matter pathways extracted from DTI-MRI for infants at risk of developing autism. Warmer colors represent greater fractional anisotropy values. Image courtesy of the University of North Carolina and the American Journal of Psychiatry.

Using diffusion-tensor MRI (DTI-MRI), researchers have discovered significant differences in early brain development in high-risk infants who later develop autism, compared with those who do not develop the disorder, according to a study published online February 17 in the American Journal of Psychiatry.
The results suggest that autism develops over time during infancy, raising the possibility that targeted intervention could interrupt disease progression, said lead study author Jason Wolff, PhD, a postdoctoral fellow at the Carolina Institute for Developmental Disabilities (CIDD) of the University of North Carolina.
The preliminary findings may be a significant first step toward developing a biomarker that could be used to help diagnose autism, he noted.
Autism development
Previous studies have found that siblings of children with autism are at higher-than-average risk for developing the disorder, Wolff and colleagues wrote. Behavioral features of autism begin to emerge at approximately 12 months of age after a period of relatively normal postnatal development. Early studies also have shown that MRI can be used to detect significantly larger than normal brain volume in 2- and 3-year-old children with autism.
"Taken together, findings from the behavioral studies and the [MRI] studies of brain and head size growth in high-risk infant siblings suggest that the latter half of the first year of life is a pivotal time for both brain changes and symptom onset in infants later diagnosed with [autism]," the authors wrote.
Therefore, Wolff and colleagues began a prospective study using DTI-MRI to gauge the development of white-matter fiber tracts in 92 children at age 6, 12, and 24 months. The children were considered at risk for autism because they had an older brother or sister with the affliction. The researchers focused on white-matter fiber tracts because they act as pathways to connect different brain regions.
The study included all high-risk infants who received DTI-MRI scans at six months and behavioral assessments at 24 months, as of June 2011. Symptoms of autism spectrum disorders (ASDs) were measured at 24 months using the Autism Diagnostic Observation Schedule.
The researchers excluded infants who, among other factors, had a medical condition that would affect brain development, had sensory impairment or low birth weight, or were born prematurely. They also omitted young children who were exposed to specific medications or neurotoxins and exhibited contraindications for MRI.
The high-risk infants were divided into two groups, according to whether they were ASD-negative or ASD-positive. At 24 months, 28 infants met the criteria for ASDs, while 64 did not. The study group used the Autism Diagnostic Observation Schedule to calculate symptom severity scores, ranging from 1 for the least severe to 10 for the most severe. Scores of 4 or greater denoted the presence of autism.
Brain scans were performed on identical 3-tesla MRI scanners (Tim Trio, Siemens Healthcare) with 12-channel head coils while patients were sleeping. The DTI-MRI sequence was acquired with a field-of-view of 190 mm for 6- and 12-month-old children and 209 mm for 24-month-old children. Most subjects also had additional brain imaging scans performed at either 12 or 24 months, or at both time points.

White-matter pathways
The researchers found that the ASD-positive and ASD-negative groups differed in white-matter fiber tract development as measured by fractional anisotropy, which assesses white-matter organization based on the movement of water molecules through brain tissue.
Wolff and colleagues examined 15 separate fiber tracts. They found significant differences in fractional anisotropy trajectories in 12 of the 15 tracts between infants who developed autism and those who did not develop the disorder.

In addition, infants who developed autism had elevated fractional anisotropy values at six months, but then experienced slower change over time. By 24 months, infants with autism had lower fractional anisotropy values compared to infants without autism.
"These results suggest that aberrant development of white-matter pathways may precede the manifestation of autism symptoms in the first year of life," the authors concluded.
Wolff and colleagues also noted that the presence of "significant differences in fractional anisotropy at six months raises the exciting possibility of developing imaging biomarkers for risk of ASDs in advance of symptom onset. Future work might investigate the potential of predictive models for ASDs in early infancy, a process that could include refined imaging techniques or combined biobehavioral markers," they wrote.
Identifying high-risk infants before autism manifests itself "offers the possibility of implementing interventions that could reduce or even prevent the manifestation of the full syndrome," they added.
The results are the latest findings from the ongoing Infant Brain Imaging Study (IBIS) Network, which is funded by the U.S. National Institutes of Health and is headquartered at the University of North Carolina.

fonte: Auntminnie

quarta-feira, 15 de fevereiro de 2012

12th International Symposium on Radiation Physics

12th International Symposium on Radiation Physics
The meeting will be held in Rio de Janeiro at Instituto Militar de Engenharia - IME. The site of the event is situated on Praia Vermelha, Urca. The place is well served by public transportation within the city and offers convenient access to the International Airport. Transportation by bus from and to the main hotels and strategic points of the city will be provided by the organization
The aim of ISRP-12 is to provide a forum for the discussion of developments and applications encompassing, but not limited to:
  • Fundamental processes in radiation physics
  • Quantitative photon and particle analytical techniques
  • Absorption and fluorescence spectroscopy (XAFS, XANES, XRF, Raman…)
  • Radiation Sources and detectors
  • Simulation codes and radiation transport
  • Application to material science
  • Medical and biomedical applications
  • Applications to space, earth and environmental sciences
  • Cultural heritage and art
  • New technologies and industrial applications
  • Radiation physics and Nuclear fuel cycle

The meeting will include plenary talks, progress reports, hot topics and poster presentations. ISRP-12 will consist of both oral and poster sessions. The oral sessions will include invited and contributed papers. The latter will be selected by the Scientific Programme Committee among the poster submissions whose authors indicate their preference for oral presentation. A prize for the best young researcher paper presented orally will be given.
A local social program will be organized for participants and accompanying persons that will enhance their visit to Rio, recognized as “one of the world's most beautiful cities”, and we invite you to share our rich and diverse culture during your visit. Participants may also choose to take the opportunity to visit other regions in Brazil before or after the Symposium.

Workshop on Radioprotection Dosimetry
A Workshop on Radioprotection Dosimetry will be held from Wednesday 03 to Friday 05 of October at the Nuclear Energy Research Institute, in São Paulo. Expert hosts of the workshop will bring extensive international experience and will stress applications in geology, conservation science and forensic science.