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The detection and determination of some trace element impurities in Technetium-99m generator eluatesConrow, E. H. (Edmund H.), 1949- January 1974 (has links)
No description available.
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The effect of reconstruction algorithms (iterative versus filtered backprojection) on the diagnosis of single pulmonary nodules using Thallium-201 and Technetium-99m MIBI SPECTAmbayi, Rudo 04 1900 (has links)
Thesis (MScMed)--Stellenbosch University, 2004. / Copy not signed by author. / ENGLISH ABSTRACT: This study involved 33 patients, 19 men and 14 women. The age range was wide (20-90
years) and median age was 57 years. These patients had a single pulmonary nodule (SPN)
defined radiologically as a well defined, round or oval intrapulmonary lung lesion not
associated with atelectasis or adenopathy on chest radiography or computed tomography.
Patients were investigated with Tc-99m MIBI and TI-201 (25 patients) and with Tc-99m
MIBI alone (8 patients). Single photon emission computed tomography images were
reconstructed using both iterative reconstruction (Ordered Subsets - Expectation
Maximisation: aSEM) and filtered backprojection (FBP), on the Hermes system.
Transverse, coronal and sagittal slices were displayed on the screen using a grey scale.
The aSEM and FBP images for each study were co-registered semi-automatically using
the multimodality programme on the Hermes. The best slice for the lesion was chosen
according to the best view used to locate the SPN on chest radiograph. Regions of interest
(Ral) were drawn manually outside the outer margin of the detected lesion, first on the
aSEM image. This was automatically mirrored on the co-registered FBP image.
For most patients, the background was automatically mirrored horizontally on the
contralateral side, again, first on the OSEM then automatically on the FBP image.
Automatic vertical mirroring or manual horizontal mirroring was used when background
was found to be in a visually 'hot' area like the heart or vertebrae. The average counts
and standard deviation of the Ral and background were generated automatically.
Semi-quantitative image analysis was done by calculating the signal-to-noise ratio (SNR)
and tumour-to-background (TIB) ratio using the following formulae:
SNR = Mean counts ROI(lesion) - Mean counts background
Standard deviation background
TIB rati.o = -M---e-a-n-'--c-o--u-n-'t-s- ROI(lesion)
Mean counts background
Detection was found to be the same for the two reconstruction algorithms, that is, every
lesion detected by using OSEM could also be detected by using FBP.
However lesion detection did differ between Tl-201 and Tc-99m-MIBI.
Sensitivity and specificity were calculated for different thresholds of SNR and TIB ratios.
Receiver operating characteristics (ROC) curves were drawn to represent the different
sensitivities and specificities at each threshold. Tuberculosis (TB) was not included in
this analysis as uptake of Tl-20l was found to be significantly high and comparable to
that of malignant nodules. However the effect of OSEM and FBP on the 'positive' TB
nodules was assessed separately. By calculating the area under the ROC curves, TI-201
using OSEM was shown to be more accurate at differentiating malignant nodules from
benign ones than FBP. Although this difference was not statistically significant (p=0.1 0),
there was a clear tendency. The two reconstruction algorithms were found to be almost
equally accurate, when using Tc-99m-MIBI, the difference between them being
considerably insignificant.
In conclusion, it was shown that there is a tendency that OSEM outperforms FBP for
studies using Tl-201 but not for Tc-99m-MIBI. / AFRIKAANSE OPSOMMING: Hierdie studie sluit 33 pasiënte in, 19 mans en 14 vroue. Die ouderdomme wissel tussen
20 en 90 jaar met 'n gemiddelde ouderdom van 57 jaar. Elkeen van die pasiënte het 'n
enkel longnodule (SPN) op borskas X-straal en/of rekenaar tomografie getoon, wat
radiologies gedefinieer word as 'n goed omskrewe, ronde of ovaal intrapulmonale
longletsel wat nie met atelektase of adenopatie geassosieer is nie.
Pasiënte is met Tc-99m MIDI en TI-201 (25 pasiënte) of slegs met Tc-99m MIBI (8
pasiënte) ondersoek. Enkelfoton emissie rekenaar tomografiese (EFERT) beelde is met
beide iteratiewe rekonstruksie (Ordered Subsets - Expectation Maximisation: OSEM) en
gefilterde terugprojeksie (FBP) met die Hermes sisteem gerekonstrueer.
Transvers, koronale en sagittale snitte is in grysskaal op die sisteem vertoon. Die OSEM
en FBP beelde vir elke studie is semi-outomaties gekoregistreer met behulp van die
multimodaliteitsprogram op die Hermes. Die optimale snit vir elke letsel is gekies
volgens die beste aansig op die borskas X-straalom die SPN te lokaliseer. Gebiede van
belang (ROl) is met die hand buite-om die buitenste rand van die letsel getrek op die
OSEM beeld en daarna outomaties in die ooreenstemmende area op die gekoregistreerde
FPB beeld geplaas.
Vir die meeste pasiënte is die agtergrond outomaties as horisontale spieëlbeeld op die
kontralaterale kant geplaas, eers op die OSEM en dan outomaties op die FBP beeld. 'n
Outomatiese vertikale spieëlbeeld of manuele horisontale verskuiwing van die
agtergrondsarea is gedoen indien die agtergrond oorvleuel het met 'n 'warm' area soos
die hart of werwels. Die gemiddelde tellings en standaardafwyking van die ROl en
agtergrond is outomaties gegenereer.
Semi-kwantitatiewe beeldanalise is gedoen deur berekening van die sein-tot-agtergrond
verhouding (signal-to-noise ratio - SNR) en tumor-tot-agtergrond (TIB) verhouding met
behulp van die volgende formules:
SNR = gemiddelde tellings ROI(letsel) - gemiddelde tellings agtergrond
Standaard afwyking van agtergrond
TIB rati.o = -g=em--id-d-e-l-d-e--te=ll-in-g-s__R:_O-I(-le-t-s'e-l)
gemiddelde tellings agtergrond
Opsporing is soortgelyk bevind vir die twee rekonstruksie algoritmes, dit wil sê elke
letselopgespoor met behulp van OSEM kon ook met FBP opgespoor word.
Letselwaameming het egter verskil tussen TI-201 en Tc-99m-MIBI.
Sensitiwiteit en spesifisiteit is vir verskillende drempels van SNR en TIB verhoudings
bereken. 'Receiver operating characteristics' (ROC) kurwes is getrek om die verskillende
sensitiwiteite en spesifisiteite by elke drempel te verteenwoordig. Tuberkulose (TB) is nie
in hierdie analise ingesluit nie aangesien opname van Tl-201 beduidend hoog en
vergelykbaar met die van maligne nodules was. Die effek van OSEM en FBP op die
'positiewe' TB nodules is egter apart beoordeel. Deur berekening van die area onder die
ROC kurwes, is getoon dat OSEM van Tl-201 tomografiese data meer akkuraat as FBP
was om maligne van benigne nodules te onderskei. Alhoewel hierdie verskil nie statisties
betekenisvol was nie (p=0.10), is daar wel 'n duidelike neiging gevind. Die twee
rekonstruksie algoritmes was byna ewe akkuraat wanneer Tc-99m-MIBI gebruik is, met
duidelik geen betekenisvolle verskil tussen die algoritmes nie.
Gevo lgtrekking
In hierdie studie is dit getoon dat daar 'n neiging is dat OSEM beter vaar as FBP vir
studies met tallium-201 maar nie vir Tc-99m-MIBI nie.
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Desenvolvimento de um radiofármaco para marcação com Tc-99m para a identificação de infecção utilizando um peptídeo catiônico sintético / Development of a Tc-99m labeling radiopharmaceutical for infection identification using a synthetic cationic peptideDIAS, LUIS A.P. 03 February 2016 (has links)
Submitted by Claudinei Pracidelli (cpracide@ipen.br) on 2016-02-03T12:08:21Z
No. of bitstreams: 0 / Made available in DSpace on 2016-02-03T12:08:21Z (GMT). No. of bitstreams: 0 / Tese (Doutorado em Tecnologia Nuclear) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
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Desenvolvimento de um radiofármaco para marcação com Tc-99m para a identificação de infecção utilizando um peptídeo catiônico sintético / Development of a Tc-99m labeling radiopharmaceutical for infection identification using a synthetic cationic peptideDIAS, LUIS A.P. 03 February 2016 (has links)
Submitted by Claudinei Pracidelli (cpracide@ipen.br) on 2016-02-03T12:08:21Z
No. of bitstreams: 0 / Made available in DSpace on 2016-02-03T12:08:21Z (GMT). No. of bitstreams: 0 / O crescimento anual no número de procedimentos realizados em Medicina Nuclear se deve em primeiro lugar à vantagem de não serem invasivos. Cerca de 80% dos diagnósticos realizados em Medicina Nuclear utilizam radiofármacos preparados com tecnécio-99m devido a suas características físicas ideais, disponibilidade e baixo custo. Dentre os radiofármacos utilizados para identificar processos de infecção e inflamação estão os leucócitos marcados com tecnécio-99m, considerado o padrão ouro e o citrato de gálio (67 Ga), atualmente comercializado no Brasi. Os leucócitos marcados possuem a desvantagem da técnica laboriosa de marcação nem sempre disponível nos centros de Medicina Nuclear, enquanto o citrato de gálio (67 Ga) não é específico e possui energias desfavoráveis para a dosimetria do paciente e para a aquisição de imagens. Neste cenário, novas moléculas para diagnóstico de focos de infecção têm sido pesquisadas, particularmente envolvendo biomoléculas, como os peptídeos antimicrobianos. Nesta categoria, a Ubiquicidina na forma de um fragmento sintético (UBI 29-41) despertou o interesse de pesquisadores que estudaram a marcação com tecnécio-99m utilizando métodos direto e indireto. Um reagente liofilizado de UBI 29-41descrito na literatura demonstrou eficácia no diagnóstico de focos de infecção utilizando-se imagens cintilográficas, porém o produto não está disponível no Brasil. O objetivo deste trabalho foi estudar a marcação do fragmento de UBI 29-41 com tecnécio-99m por método direto e avaliar a utilização de soluções tampão no procedimento de marcação, de modo a flexibilizar o volume da solução de pertecnetato de sódio a ser utilizado, o que constitui aspecto de ineditismo deste trabalho. O fragmento foi radiomarcado com diferentes volumes de soluções tampão alcalinas (carbonato e fosfato) e a utilização dos tampões em substituição à solução de hidróxido de sódio possibilitou realizar a marcação com diferentes volumes da solução de pertecnetato de sódio, sem comprometimento do rendimento de marcação. Uma formulação liofilizada foi avaliada, demonstrando estabilidade por período de 12 meses, viabilizando a produção rotineira do agente de marcação. Os estudos de biodistribuição das preparações efetuadas com os diferentes tampões demonstraram que os complexos formados apresentam características gerais de biodistribuição semelhantes ao composto padrão descrito na literatura, incluindo rápido clareamento sanguíneo e alta captação renal, condizente com a eliminação do produto por esta via. Entretanto, as preparações estudadas apresentaram captação hepática maior e captação renal menor que o composto padrão. As preparações estudadas captaram no foco de infecção provocado por S.aureus e demonstraram potencial para aplicação clínica no diagnóstico em Medicina Nuclear. Como pré-requisito para a realização de estudos clínicos de um novo composto foi realizado estudo de cito e genotoxicidade, cujos resultados demonstraram a segurança das preparações estudadas. / Tese (Doutorado em Tecnologia Nuclear) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
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Medical radionuclides and their impurities in wastewaterHay, Tristan Ryan 24 May 2014 (has links)
NCRP report No.160 states that medical exposure increased to nearly half of the total radiation exposure of the U.S. population from all sources in 2006 (NCRP 2009). Part of this increase in exposure is due to the rise in nuclear medicine procedures. With this observed growth in medical radionuclide usage, there is an increase in the radionuclide being released into wastewater after the medical procedures. The question then arises: what is the behavior of medical radionuclides and their impurities in the wastewater process? It is important to note that, often, medical radionuclides are not exactly 100% radionuclide pure, but they meet a certain standard of purity. Of particular interest are the longer lived impurities associated with these medical radionuclides. The longer lived impurities have a higher chance of reaching the environment. The goal of this study is to identify the behavior of medical radionuclides and their impurities associated with some of the more common radiopharmaceuticals, including Tc-99m and I-131, and locate and quantify levels of these impurities in municipal wastewater and develop a model that can be used to estimate potential dose and risk to the public. / Graduation date: 2012 / Access restricted to the OSU Community at author's request from May 24, 2012 - May 24, 2014
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