Evaluación de la recurrencia de tumores musculoesqueléticos mediante gammagrafía complementada con SPECT/CT con talio-201 en población pediátrica / Evaluation of recurrence of musculoskeletal tumors with thallium-201 scintigraphy plus SPECT/CT in pediatric population

Resumen Introducción: Los estudios de imagen, como la tomografía simple y contrastada, son la primera aproximación diagnóstica para detectar la recurrencia de tumores musculoesqueléticos. El objetivo de este estudio retrospectivo fue demostrar la utilidad de la gammagrafía acoplada a tomografía computarizada por emisión de fotón único (SPECT/CT) con talio-201(201Tl) en la valoración de tumores musculoesqueléticos malignos con sospecha de recurrencia o enfermedad metastásica. Métodos: Se realizaron 72 estudios gammagráficos y de SPECT/CT para la valoración de la recurrencia locorregional y a distancia, al menos 8 semanas tras la última terapia, en 42 pacientes con diferentes tipos de tumores musculoesqueléticos malignos, como osteosarcoma, sarcoma de Ewing, rabdomiosarcoma, retinoblastoma, sarcoma sinovial y tumor de Wilms en el Hospital Infantil de México. Se calcularon el valor predictivo positivo (VPP) y el intervalo de confianza del gammagrama y de la SPECT/CT en comparación con el resultado del análisis histopatológico y el seguimiento clínico y radiológico para identificar la recurrencia. Resultados: La gammagrafía fue anormal en 30 (71.4%) de los 42 pacientes. Se detectaron 33 lesiones (30 pacientes) por gammagrafía y 25 (21 pacientes) por telerradiografía de tórax y tomografía de dos regiones. La SPECT/CT se realizó en 30 pacientes y se detectaron 12 lesiones adicionales al rastreo planar. El VPP con la gammagrafía fue del 82%, y con la SPECT/CT, del 100%. Conclusión: La gammagrafía con 201Tl puede considerarse un estudio adecuado para identificar los sitios de viabilidad tumoral, con alto grado de certeza diagnóstica al complementar con SPECT/CT.

Abstract Background: Imaging studies, particularly simple and contrast-enhanced tomography, constitute the first diagnostic approach to detect recurrence of musculoskeletal tumors. The aim of the present retrospective study was to demonstrate the usefulness of scintigraphy plus SPECT/CT (single photon emission computed tomography) with thallium-201 (201Tl) in the evaluation of malignant musculoskeletal tumors with suspicion of recurrence or metastatic disease. Methods: Eight weeks after the last therapy, 72 scintigraphy and SPECT/CT studies were performed to assess regional recurrence and metastatic disease in 42 patients with different types of malignant musculoskeletal tumors, such as osteosarcoma, Ewing's sarcoma, rhabdomyosarcoma, retinoblastoma, synovial sarcoma, and Wilms tumor at the Hospital Infantil de México Federico Gómez. The positive predictive value (PPV) and the confidence interval of the scintigraphy and SPECT/CT were calculated when compared with the results of the histopathological analysis and the clinical and radiological follow-up for the identification of recurrence. Results: Scintigraphy was abnormal in 30 (71.4%) of the 42 patients; 33 lesions (30 patients) were detected by scintigraphy and 25 lesions (21 patients) by chest X-ray and tomography of two regions. The SPECT/CT was performed on 30 patients, where 12 lesions were detected in addition to the planar scintigraphy. Scintigraphy showed a PPV of 82%; SPECT/CT, 100%. Conclusion: 201Tl-scintigraphy can be considered as an adequate study to identify the sites of tumor viability with a high degree of diagnostic certainty combined with the SPECT/CT technique.

Clinical utility of left ventricular ejection fraction reserve by stress thallium-201 myocardial gated single photon computed tomography among patients with and suspected coronary artery disease

BACKGROUND: Coronary microcirculation impairment with sequential decrease in cardiac function is reflected by abnormal left ventricular ejection fraction reserve (LVEFR),which precedes diagnostic evidence of myocardial insult. However, prognostic utility of LVEFR is less, if not least explored. The aim of this study was to evaluate the clinical utility of LVEFR in predicting major cardiac events (MACE) among patients with and suspected coronary artery disease (CAD).MATERIALS AND METHODS: A retrospective cohort study of 245 patients who underwent stress thallium-201 myocardial perfusion scan (MPS) was conducted. The patients were categorized as having normal or abnormal perfusion scan. Each group was subdivided into normal and abnormal LVEFR groups. All subjects were followed up for any major adverse cardiac events 36 months after MPS through review of hospital records.RESULTS: There was an overall increase in the likelihood of cardiac events with abnormal LVEFR (i.e., odds ratio of 2.99,p=CONCLUSION: Abnormal LVEFR can be used as an independent predictor of cardiac events which can be observed in subjects with normal and abnormal perfusion scans alike.

Clinical utility of left ventricular ejection fraction reserve by stress thallium-201 myocardial gated single photon computed tomography among patients with and suspected coronary artery disease

BACKGROUND: Coronary microcirculation impairment with sequential decrease in cardiac function is reflected by abnormal left ventricular ejection fraction reserve (LVEFR),which precedes diagnostic evidence of myocardial insult. However, prognostic utility of LVEFR is less, if not least explored. The aim of this study was to evaluate the clinical utility of LVEFR in predicting major cardiac events (MACE) among patients with and suspected coronary artery disease (CAD).MATERIALS AND METHODS: A retrospective cohort study of 245 patients who underwent stress thallium-201 myocardial perfusion scan (MPS) was conducted. The patients were categorized as having normal or abnormal perfusion scan. Each group was subdivided into normal and abnormal LVEFR groups. All subjects were followed up for any major adverse cardiac events 36 months after MPS through review of hospital records.RESULTS: There was an overall increase in the likelihood of cardiac events with abnormal LVEFR (i.e., odds ratio of 2.99,p=CONCLUSION: Abnormal LVEFR can be used as an independent predictor of cardiac events which can be observed in subjects with normal and abnormal perfusion scans alike.

Value of Tl-201 imaging in predicting therapeutic I-131 uptake in patients with thyroglobulin-positive but I-131 scan negative differentiated thyroid cancer

BACKGROUND: Serum thyroglobulin assays and I-131 imaging and routinely employed for the detection of remaining functioning thyroid tissue after surgery and radioiodine therapy. However, the sensitivity of I-131 is suboptimal resulting in cases of positive thyroglobulin test but negative I-131 imaging, potentially creating a dilemma in subsequent therapeutic management. Other radiopharmaceuticals, such as TI-201 may offer better sensitivity, although it is not clear whether this contributes to the decision-making for subsequent I-131therapy. This prospective cohort study aimed to determine if Tl-201 imaging identified thyroid tissues that will take up therapeutic I-131, and to help define its clinical utility.METHODS: Fourteen consecutive patients who underwent surgery for well-differentiated thyroid cancer, had I-131 therapy at least eight months previously, and with elevated thyroglobulin (>10 ng/mL) but negative pre-therapy (111 MBq) I-131 whole body scan (WBS), were enrolled in the study. WBS was done using 56.74 MBq of Tl-201. All patients had repeat I-131 ablation (3.7-7.4GBq) one to two months after Tl-201 imaging. Post-therapy WBS was done four to seven days after.RESULTS: All 14 patients had papillary thyroid carcinoma. Ten patients had a positive Tl-201 scan. Of the 14 subjects, only two had a positive post-therapy I-131 WBS, both whom had a positive Tl-201 scan. Thallium-201 scanning showed a fairly high sensitivity (71%) in demonstrating thyroid remnants or metastases using a thyroglobulin level of >10 ng/mL as standard. However, a positivel Tl-201 scan only has a predictive value of 20% for subsequent uptake of therapeutic I-131 as shown in the post-therapy scan.CONCLUSION: Thallium-201 uptake correlates poorly with therapeutic I-131 uptake in thyroglobulin-positive, but I-131 scan-negative, differentiated thyroid cancer patients. Results of this study suggest that the presence of thyroid remnants and metastases on Tl-201 imaging is inappropriate as a basis for subsequent I-131 therapy.

Value of Tl-201 imaging in predicting therapeutic I-131 uptake in patients with thyroglobulin-positive but I-131 scan negative differentiated thyroid cancer

BACKGROUND: Serum thyroglobulin assays and I-131 imaging and routinely employed for the detection of remaining functioning thyroid tissue after surgery and radioiodine therapy. However, the sensitivity of I-131 is suboptimal resulting in cases of positive thyroglobulin test but negative I-131 imaging, potentially creating a dilemma in subsequent therapeutic management. Other radiopharmaceuticals, such as TI-201 may offer better sensitivity, although it is not clear whether this contributes to the decision-making for subsequent I-131therapy. This prospective cohort study aimed to determine if Tl-201 imaging identified thyroid tissues that will take up therapeutic I-131, and to help define its clinical utility.METHODS: Fourteen consecutive patients who underwent surgery for well-differentiated thyroid cancer, had I-131 therapy at least eight months previously, and with elevated thyroglobulin (>10 ng/mL) but negative pre-therapy (111 MBq) I-131 whole body scan (WBS), were enrolled in the study. WBS was done using 56.74 MBq of Tl-201. All patients had repeat I-131 ablation (3.7-7.4GBq) one to two months after Tl-201 imaging. Post-therapy WBS was done four to seven days after.RESULTS: All 14 patients had papillary thyroid carcinoma. Ten patients had a positive Tl-201 scan. Of the 14 subjects, only two had a positive post-therapy I-131 WBS, both whom had a positive Tl-201 scan. Thallium-201 scanning showed a fairly high sensitivity (71%) in demonstrating thyroid remnants or metastases using a thyroglobulin level of >10 ng/mL as standard. However, a positivel Tl-201 scan only has a predictive value of 20% for subsequent uptake of therapeutic I-131 as shown in the post-therapy scan.CONCLUSION: Thallium-201 uptake correlates poorly with therapeutic I-131 uptake in thyroglobulin-positive, but I-131 scan-negative, differentiated thyroid cancer patients. Results of this study suggest that the presence of thyroid remnants and metastases on Tl-201 imaging is inappropriate as a basis for subsequent I-131 therapy.

Evaluation of a novel decorporation approach to prevent radioactivity uptake by using acidosis in experimental animals.

With an aim to devise a prophylactic and/or therapeutic approach for preventing internalization of radiothallium (201Tl), and more importantly by implication, its chemical analogue radiocesium (137Cs) during any nuclear emergency, different ex vivo and in vivo animal models were created to determine the role of pH in absorption of 201Tl across jejunum/muscle tissue and whole body retention of 201Tl respectively. Movement of Tl+ under simulated pH conditions proved that pH had direct influence on its absorption. Oral intake of acidified water or parenteral administration of lactic acid was able to reduce the body burden of 201Tl by up to 12 and 50% respectively. The results indicate that acidification of gut, within physiological range may be used as an option for decorporation/inhibition of incorporation of radiothallium and radiocesium, particularly in cases of mass casualty.

Serial myocardial imaging after a single dose of Thallium-201

Although thallium-201 exercise scintigraphy has been established for the detection of myocardial ischemia and viability, little is known regarding the myocardial thallium-201 kinetics during angioplasty. Herein, we report a 77-year old man with angina pectoris, in whom serial myocardial imaging after a single dose of thallium-201 was helpful in identifying not only the culprit lesion and myocardial viability, but also the dynamic changes in myocardial perfusion during angioplasty. Thallium-201 images after exercise showed a perfusion defect in the inferior wall, with a trivial redistribution 3 hours after the exercise and a marked improvement 24 hours later. Coronary angiography, performed 27 hours after exercise scintigraphy, showed severe stenosis in the right coronary artery. Guidewire crossing of the lesion interrupted the antegrade flow, which was restored after balloon dilation and stent implantation. Thallium-201 images, 2 hours after angioplasty [i.e., 30 hours after exercise], showed a decreased tracer uptake in the inferior wall, which improved the next day [i.e., 48 hours after exercise]. Cardiac biomarkers were negative in the clinical course

Twenty four hour imaging delay improves viability detection by Tl-201 myocardial perfusion scintigraphy / Atraso de imagem de 24 horas melhora a viabilidade de detecção por cintilografia de perfusão miocárdica Tl-201

OBJECTIVE: Since twenty-four-hour imaging by Tl-201 myocardial perfusion scintigraphy has been introduced as an effective additional procedure, the aim of this study was to compare this method's result with only rest redistribution procedure in the diagnosis of myocardial viability. METHODS: Thirty patients (Seven female, 23 male; mean: 59.8 ± 10.7, 55.8-63.8 years old) with diagnosis of coronary artery disease were involved in this study. All patients had anamnesis of previous myocardial infarction and/or total occlusion of any main artery in the coronary angiography. Myocardial perfusion scintigraphy with Tl-201 with rest four hour (early) redistribution and 24 hour delayed redistribution protocol were performed to all of the patients. The images were evaluated according to 17 segment basis by an experienced nuclear medicine physician and improvement of a segment by visual interpretation was considered as viable myocardial tissue. RESULTS: Viability was found at 52 segments in the early redistribution images and additional 18 segments in the 24 hour delayed redistribution images on segment basis in the evaluation of 510 segments of 30 patients. On per patient basis, among the 26 patients who had viable tissue, 14 (54%) had additional improvement in 24 hour delayed images. Three (12%) patients had viable tissue in only 24 hour delayed images. CONCLUSION: Delayed imaging in Tl-201 MPS is a necessary application for the evaluation of viable tissue according to considerable number of patients with additional improvement in 24 hour images in our study, which is restricted to the patients with myocardial infarct.

OBJETIVO: Dado que a cintilografia Tl -201 24 horas de imagens por perfusão miocárdica foi introduzida como um procedimento adicional efetivo, assim, o objetivo deste estudo foi comparar os resultados deste método com o procedimento único de redistribuição no diagnóstico de viabilidade miocárdica. MÉTODOS: Trinta pacientes (Sete mulheres, 23 homens, média: 59,8 ± 10,7, 55,8-63,8 anos) com diagnóstico de doença arterial coronariana foram avaliados neste estudo. Todos os pacientes tinham anamnese de infarto do miocárdio e/ou oclusão total de uma artéria principal na cinecoronariografia. Cintilografia de perfusão miocárdica com protocolo de Tl-201 em repouso, redistribuição quatro horas (início) e redistribuição tardia 24 horas foi realizada em todos os pacientes. As imagens foram avaliadas de acordo com a base de 17 segmentos por um médico com experiência em medicina nuclear e melhoria de um segmento por interpretação visual foi considerado como tecido miocárdico viável. RESULTADOS: A viabilidade foi encontrada em 52 segmentos de redistribuição das imagens iniciais e 18 segmentos adicionais nas imagens de redistribuição tardias de 24 horas baseadas em segmento, na avaliação de 510 segmentos de 30 pacientes. Em termos de pacientes, entre os 26 pacientes que tinham tecido viável, 14 (54%) apresentaram melhora adicional em imagens tardias de 24 horas. Três (12%) pacientes tiveram tecido viável apenas em imagens tardias de 24 horas. CONCLUSÃO: A imagem tardia em TL- 201 MPS é uma aplicação necessária para a avaliação do tecido viável de acordo com o número considerável de pacientes com melhora adicional em imagens de 24 horas em nosso estudo, o qual é restrito aos pacientes com infarto do miocárdio.

Physical filtering yields scatter compensation in single photon emission computed tomography [SPECT] at some degree

In Single Photon Emission Computed Tomography [SPECT] scattering of gamma Photons are considered to be inherent draw back of SPECT because in currently detecting systems mostly Nal [TI] sodium Iodied activated Thallium detectors are used, which has poor energy resolution as compared to other solid state detectors. Due to poor energy resolution some noticeable amount of scattered photons are registered in primary photo peak of single standard energy window 20% [centered at 140 keV] for Tc-99m radio nuclide. The registration of scatter gamma photons may affect the primary data and results in the poor contrast and quality images. To overcome this problem in SPECT material based physical filter of suitable thickness are imposed in conjunction with single standard electronic energy window. In this method the role of physical filter is to prevent low energy gamma photons prior to register in the crystal of the detecting device

²⁰¹TI and (99m)Tc-MIBI scintigraphy in evaluation of neoadjuvant chemotherapy for osteosarcoma / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To evaluate the application of ²⁰¹TI and (99m)Tc-MIBI scintigraphy in assessment of neoadjuvant chemotherapy for osteosarcoma.</p><p><b>METHODS</b>Twenty-two patients with osteosarcoma underwent both ²⁰¹TI and (99m)Tc-MIBI scintigraphy. According to tumor necrosis rate (TNR), 22 patients were classified into three groups: Group 1(necrosis less than 50%), Group 2(50% ≊ 89% necrosis) and Group 3(necrosis greater than 90%). The uptake ratio(UR) was obtained in images before and after chemotherapy. The alteration ratio(AR) and tumor necrosis ratio (TNR) were calculated.</p><p><b>RESULTS</b>In ²⁰¹Tl images,UR(pre) and UR(post) (mean ± s.d.) of Group 1 were 2.14 ± 0.67, 2.07 ± 0.71 (P>0.05); UR(pre) and UR(post)of Group 2 were 3.45 ± 1.57 and 2.02 ± 0.97 (P<0.01); UR(pre) and UR(post) of Group 3 were 3.57 ± 0.67 and 1.36 ± 0.20 (P<0.01). In (99m)Tc-MIBI images, UR(pre)and UR(post) of Group 1 were 1.66 ± 0.42 and 1.85 ± 0.70 (P>0.05); UR(pre) and UR(post) of Group 2 were 2.39 ± 1.41 and 1.68 ± 0.72 (P<0.05);UR(pre) and UR(post) of Group 3 were 2.56 ± 0.60 and 1.19 ± 0.14 (P<0.01). The AR value in (201)Tl scintigraphy was -0.03-0.72, the liner regression analysis of AR versus TNR showed a highly significant positive correlation (r=0.95). The AR value in (99m)Tc-MIBI scintigraphy was -1.21-0.64, the liner regression analysis of AR versus TNR showed a highly significant positive correlation (r=0.71). The liner regression analysis of AR in ²⁰¹TI scintigraphy versus AR in (99m)Tc-MIBI scintigraphy showed a highly significant positive correlation (r=0.70).</p><p><b>CONCLUSION</b>The AR changes significantly after neoadjuvant chemotherapy and is positively correlated with TNR, which indicates that ²⁰¹TI- and (99m)Tc-MIBI scintigraphy can be used for evaluation of neoadjuvant chemotherapy.</p>

Influência do uso do bicarbonato de sódio na cintilografia miocárdica com tálio-201 para pesquisa de viabilidade miocárdica / Influence of sodium bicarbonate in myocardial scintigraphy with 201TL for myocardial viability assessment

Fundamentos: Estudos já publicados demonstraram que o bicarbonato de sódio administrado 30 minutos antes da injeção do Tálio-201 aumenta a captação de Tálio-201 durante o estresse físico. A influência da alcalose sanguínea transitória em seres humanos antes do Tálio-201 injetado em repouso é desconhecida. Objetivo: Avaliar a influência e segurança do uso do bicarbonato de sódio na cintilografia miocárdica com Tálio-201 para pesquisa de viabilidade miocárdica. Metodologia: Entre 4/2009 e 12/2009, 15 pacientes foram submetidos à cintilografia de perfusão miocárdica comTálio-201, segundo o protocolo de repouso-redistribuição (protocolo-padrão) e uma semana depois, repetiam o exame, quando era infundido 2mEq/kg de bicarbonato de sódio a 8,4% por via intravenosa, 30 minutos antes da injeção do radiotraçador.Resultados: As imagens do protocolo com bicarbonato revelaram um número de segmentos normais maior, escoresde perfusão menores e menor número de segmentos com reversibilidade do que o protocolo tradicional. O percentual de segmentos sem reversibilidade foi equivalente em ambos os protocolos. Não houve qualquer tipo de complicaçãorelacionada ao protocolo com bicarbonato. Conclusões: A injeção de bicarbonato de sódio antes do Tálio-201 é segura e aumentou a captação do Tálio-201 pelo miócito, resultando em menor quantidade de segmentos com defeitos de perfusão quando comparada ao protocolo-padrão. Embora haja redução do número de segmentos com reversibilidade nas imagens tardias, não houve aumento dos segmentos sem viabilidade no protocolo com bicarbonato.

Background: Published studies have already demonstrated that sodium bicarbonate administered 30 minutes before a 201Tl injection increases 201Tl uptake during physical stress. The influence of transient blood alkalosis in humans prior to injecting 201Tl at rest is unknown. Objective: To evaluate the influence and safety of sodiumbicarbonate used during myocardial scintigraphy with 201Tl for myocardial feasibility assessment. Methods: Between April and December 2009, fifteen patients underwent rest-redistribution 201Tl myocardial perfusion scintigraphy (standard protocol), repeated 1 week later, when 2mEq/kg of sodium bicarbonate were injected intravenously 30 minutes before the radiotracer injection. Results: The bicarbonate protocol images revealed more normal segments, with lower perfusion scores and fewer reversible segments than in the standard protocol. The percentage of non-reversible segments was equivalent in both protocols. There were no complications related to the bicarbonate protocol.Conclusions: Sodium bicarbonate injections before 201Tl are safe and enhance the 201Tl uptake by the myocyte resulting in fewer segments with perfusion defects, compared to the standard protocol. Despite a reduction inthe number of reversible segments in the later images, there was no increase in nonviable segments in the bicarbonateprotocol.

Effect of post-myocardial infarction streptokinase [SK] therapy, on myocardial viability - evaluation with thallium- 201 single photon emission computed tomography [TL-201 SPECT]

To evaluate the effect of post-myocardial infarction Streptokinase therapy on myocardial viability, employing Thallium-201 single photon emission computed tomography [TL-201 SPECT]. Retrospective, experimental study. The Nuclear Cardiology Department, Armed forces Institute of Cardiology / National Institute of Heart Diseases, Rawalpindi, from 1[st] April 2009 to 31[st] October 2009. Male patients, who had suffered from acute myocardial infarction [AMI], in an area supplied by the left anterior descending [LAD] artery, had infarct-related electrocardiogram [ECG] changes and received or did not receive Streptokinase therapy, were included. Those with a normal ECG, or history of revascularization, or non-ST elevation MI, or more than on MIs, were excluded. The patients were divided into groups 1 [who received Streptokinase] and 2 [who did not receive Streptokinase]. Each group contained 42 patients and all underwent scintigraphic viability study through intravenous injection of 3.0 mCi [123 MBq] of TL-201, followed by rest-redistribution SPECT imaging on a dual head, dedicated cardiac gamma camera system [Philips Cardio MD [registered sign]]. Emory's cardiac toolbox [registered sign] and AutoQUANT [registered sign] were used for data processing and quantitative estimation of viable myocardium. Empirical scores from 0 to 2 were assigned to each of the scans, in the order of increasing viability, and these were compared across the two groups. Group 1 contained 42 patients [age range = 38 to 80 years, mean = 53.98 +/- 11.26 years], in whom empirical viability scoring was done. Score 0 was seen in 2 patients, score 1 was seen in 15 patients and score 2 was seen in 25 patients from this group. Group 2 also contained 42 patients [age range = 38 to 80 years, mean = 56.71 +/- 9.05 years], in whom viability score of 0 was seen in 3 patients, score 1 was seen in 11 patients and score 2 was seen in 28 patients from this group. Age difference between the two groups was statistically insignificant [p = 0.223]. The myocardial viability results analysed by 3 x 2 contingency table applying chi- square [X[2]] test also showed no significant difference between groups 1 and 2 [p= 0.611]. This study did not find any significant difference in myocardial viability - post- myocardial infarction - in patients who received or did not receive Streptokinase therapy

[Compensation of cross-contamination in simultaneous 201Tl/99mTc myocardial perfusion SPECT imaging]

It is a common protocol to use 201Tl for the rest and 99mTc for the stress cardiac SPECT imaging. Theoretically, both types of imaging may be performed simultaneously using different energy windows for each radionuclide. However a potential limitation is the cross-contamination of scattered photons from 99mTc and collimator X-rays into the 201Tl energy window. We used a middle energy window method to correct this cross-contamination. Using NCAT, a typical software torso phantom was generated. An extremely thin line source of 99mTc activity was placed inside the cardiac region of the phantom and no activity in the other parts. The SimSET Monte Carlo simulator was used to image the phantom in different energy windows. To find the relationship between projections in different energy windows, deconvolution theory was used. We investigated the ability of the suggested functions in three steps: Monte Carlo simulation, phantom experiment and clinical study. In the last step, SPECT images of eleven patients who had angiographic data were acquired indifferent energy windows. All of these images were compared by determining the contrast between a defect or left ventricle cavity and the myocardium. We found a new 2D kernel which had an exponential pattern with a much higher center. This function was used for modeling 99mTc down scatter distribution from the middle window image. X-ray distribution in the 201Tl window was also modeled as the 99mTc photopeak image convolved by a Gaussian function. Significant improvements in the contrast of the simultaneous dual 201Tl images were found in each step before and after reconstruction. In comparison with other similar methods, better results were acquired using our suggested functions. Our results showed contrast improvemtn in thallium images after correction, however, many other parameters should be evaluated for clinical approaches. There are many advantages in simultaneous dual isotope imaging. It halves imaging time and reduces patient waiting time and discomfort. Identical rest/stress registration of images also facilitates physicists' motion or attenuation corrections and physicians' image interpretation

Infarto do miocárdio causado por lesão arterial coronariana após trauma torácico fechado / Infarto de miocardio causado por lesión arterial coronaria post traumatismo torácico cerrado / Myocardial infarction caused by coronary artery injury after a blunt chest trauma

Relatamos o caso de um indivíduo do sexo masculino de 29 anos de idade, vítima de um acidente de carro no qual sofreu trauma torácico fechado, evoluindo com insuficiência cardíaca congestiva. O paciente apresentava boa saúde previamente, sem sintomas de doença cardiovascular. Na avaliação inicial, o eletrocardiograma mostrou ondas Q nas derivações precordiais e o ecocardiograma mostrou disfunção ventricular esquerda importante. A angiografia coronária mostrou uma lesão na artéria coronária descendente anterior esquerda (ADE), com acinesia da parede anterior na ventriculografia com contraste. A tomografia computadorizada por emissão de fóton único (SPECT) com Tálio-201 não mostrou viabilidade. O paciente foi mantido em tratamento clínico com boa evolução.

We report the case of a 29-year-old man, victim of a car accident, who suffered a severe blunt chest trauma, with evolving congestive heart failure. He had previously had a good overall health status, with no symptoms of cardiovascular disease. At the initial assessment, the electrocardiogram showed Q waves in the precordial leads and the echocardiogram disclosed severe left ventricular dysfunction. Coronary angiogram showed a proximal left anterior descending coronary artery lesion, with anterior wall akinesis on contrast-enhanced ventriculography. A Thallium-201 single photon emission computed tomography (SPECT) showed no viability. He remained on medical treatment with good evolution.

Relatamos el caso de un individuo del sexo masculino, de 29 años de edad, víctima de accidente automovilístico en el cual sufrió traumatismo torácico cerrado, evolucionando con insuficiencia cardíaca congestiva. El paciente presentaba buena salud previamente, sin síntomas de enfermedad cardiovascular. En la evaluación inicial, el electrocardiograma mostró ondas Q en las derivaciones precordiales y el ecocardiograma mostró disfunción ventricular izquierda importante. La angiografía coronaria mostró una lesión en la arteria coronaria descendente anterior izquierda (ADI), con acinesia de la pared anterior en la ventriculografía de contraste. La tomografía computada por emisión de fotón único (SPECT) con Talio-201 no mostró viabilidad. El paciente fue mantenido en tratamiento clínico con buena evolución.

The effects of 201Tl myocardial perfusion scintigraphy studies on oxidative damage in patients / Efectos de los estudios de escintigrafía de perfusión miocárdica 201Tl sobre el daño oxidativo en los pacientes

The aim of this study was to investigate gamma radiation-induced oxidative damage in erythrocytes after 201Tl myocardial perfusion scintigraphy. Twenty patients (8 women and 12 men) who performed 201Tl myocardial perfusion scintigraphy were included in this study. The blood samples were taken from patients just before, 1 hour after and three hours after injection of the radiopharmaceutical. Malon-dialdehyde (MDA) and antioxidant enzymes such as glutathione peroxidase (GPX), superoxide dismutase (SOD) and catalase (CAT) levels were measured to evaluate the gamma radiation induced oxidative damage. The enzyme activities of SOD, GPX and CAT were decreased 1 hour after (p = 0.042, p = 0. 697 and p = 0.653 respectively) and 3 hours after (p = 0.003, p = 0. 573 and p = 0.002 respectively) injection of the radiopharmaceutical. Malondialdehyde levels were increased 1 hour after (p = 0.10) and 3 hours after (p = 0.47) injection of the radiopharmaceutical. In this study, we found that radiation due to 201Tl myocardial perfusion scintigraphy decreased the erythrocyte antioxidant levels and increased MDA levels.

El objetivo de este estudio fue investigar el daño oxidativo inducido por radiaciones gamma, sobre los eritrocitos luego de realizada una escintigrafía de perfusión miocárdica 201Tl. Veinte pacientes (8 mujeres y 12 hombres) a quienes se les realizó escintigrafía por perfusión miocárdica 201Tl, fueron incluidos en este estudio. Las muestras de sangre fueron tomadas de los pacientes antes, 1 hora más tarde, y tres horas después de inyectar el radiofármaco. Se midieron los niveles del malondialdehido (MDA) y las enzimas antioxidantes tales como la glutationa peroxidasa (GPX), superóxido dismutasa (SOD), y la catalasa (CAT), a fin de evaluar el daño oxidativo inducido por la radiación gamma. Las actividades de las enzimas SOD, GPX y CAT fueron disminuidas 1 horas después (p = 0.042, p = 0. 697 y p = 0.653 respectivamente) y tres horas (p = 0.003, p = 0. 573 y p = 0.002 respectivamente) tras la inyección del radiofármaco. Los niveles de malondialdehido fueron aumentados 1 hora después (p = 0.10) y tres horas después (p = 0.47) de la inyección del radiofármaco. En este estudio, hallamos que la radiación a causa de la escintigrafía de perfusión miocárdica 201Tl disminuyó los niveles antioxidantes del eritrocito y aumentó los niveles de MDA.

Value of thallium-201 scintigraphy in assessment of neoadjuvant chemotherapy for osteosarcoma / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To investigate the significance of Tl-201 scintigraphy for assessment of neoadjuvant chemotherapy for osteosarcoma.</p><p><b>METHODS</b>Thirty-four cases with osteosarcoma were enrolled into this study. The Tl-201 scintigraphy features including uptake ratio(UR) and size ratio(SR) were obtained in both early and delay imaging stages before and after chemotherapy. The responses of chemotherapy were classified into three grades according to the percentage of tumor necrosis in the specimens: necrosis < 50% as grade 1, necrosis of 50% approximately 90% as grade 2, diffuse necrosis > 90% as grade 3. The alteration ratio (AR) and SR were calculated according to tumor necrosis ratio (TNR).</p><p><b>RESULTS</b>Of the 6 patients with grade 1 response, the mean alteration ratios were 3.19% +/- 8.40% and -26.29% +/- 63.61% in early and delay imaging stages, respectively. Among the 18 patients with grade 2 response, the mean alteration ratios were 40.07% +/- 11.95% and 39.30% +/- 9.87%, respectively. Of the 10 patients with grade 3 response, the mean alteration ratios were 78.32% +/- 8.33% and 63.26% +/- 6.06% in early and delay imaging stages, respectively. The results of liner regression analysis of TNR of the surgical specimens showed a significantly positive correlation (r = 0.71) between AR and TNR. The lesion size was reduced in 18 cases, but unchanged in 8 and increased in 8. The liner regression analysis results showed a negative correlation between SR and TNR.</p><p><b>CONCLUSION</b>The alteration ratio changes significantly after neoadjuvant chemotherapy and has a significantly positive correlation with tumor necrosis ratio. Thallium-201 scintigraphy is helpful in the evaluation of neoadjuvant chemotherapy for osteosarcoma.</p>

Predictors of positive thallium 201 single photon emission computed tomography in patients of end stage renal disease

To study coronary artery disease [CAD] risk factors predicting positive thallium-201 single photon emission computed tomography [SPECT] indicating underlying CAD among patients of end stage renal disease. This cross-sectional [analytical] study was done at Department of Cardiology, Punjab Institute of Cardiology, from April 2004 to Dec 2007. One hundred consecutive patients with ESRD undergoing thallium SPECT as a routine screening test before renal transplant were studied. Dipyridamole thallium SPECT was performed in patients who were unable to exercise. Thallium SPECT was positive in 47 [47%] cases. There were significant differences in age, underlying diabetic nephropathy and total cholesterol levels among patients positive and negative on thallium SPECT. Among the risk factors age and underlying diabetic nephropathy were significantly associated [p<0.05] with a positive thallium SPECT in patients with ESRD. Positive thallium SPECT indicating underlying CAD was observed in a significant number of patients with ESRD awaiting renal transplant. Presence of advanced age and underlying diabetic nephropathy predict a positive thallium SPECT in this population

Enfermedad coronaria aneurism tica severa en un adolescente con angina de esfuerzo secundaria a enfermedad de Kawasaki no diagnosticada previamente / Severe aneurisma I coronary artery disease probably caused by Kawasaki disease. Report of one case

We report a 16 year old male with a history of angina on exertion. A treadmill exercise test was positive for ischemia in concordance with a Thallium-201 scintigraphy showing a septal and infero-posterior reversible myocardial perfusi¢n defect. Coronary angiography disclosed severe aneurysmal coronary artery disease. Bilateral internal mammary coronary artery bypass grafting was successfully performed. Kawasaki disease is the most likely etiology, although not confirmed.