Protocol for 18F-FDG quantification in PET-CT whole-body exams.

The aim of the present work is to propose a protocol for quantification of (18)F-FDG activities at organ level through whole body exams with Positron Emission Tomography. They were selected patients with normal uptake or a single tumor. In the period 2004-2005, 745 patients were studied. Among then, it was selected 97 adults for the normal uptake control group. The main studies were: intestine; colon, rectum, lung, lymphoma and melanoma, liver, esophagus, gonads and breasts. For "prospective screening", it were selected 20 patients with the identical physical characteristics of the control group. For internal dosimetry, the main organs should be elected according the kinetics of (18)F-FDG, either considering normal uptake or pathologies. Absorbed doses due to Computed Tomography and F-FDG uptake were estimated. Comparisons between internal and external exposures, for the same organ, point out higher doses due to external irradiation, except for bladder and kidneys. For individual dose estimation, parameters such the effective half-life should be known and this information may be achieved by an adaptation of the routine protocol.

Parathyroid glands: combination of sestamibi-(99m)Tc scintigraphy and ultrasonography for demonstration of hyperplasic parathyroid glands.

OBJECTIVE: To determine the frequency of the types of parathyroid gland hyperplasia and the sensitivity of sestamibi-(99m)Tc (MIBI) scintigraphy and ultrasonography (US) of patients with secondary hyperparathyroidism (SHPT) due to chronic renal failure. MATERIAL AND METHODS: We studied 43 patients with SHPT (26 females and 17 males with age range of 27-75 years). Blood tests were performed to determine intact parathyroid hormone (PTH), calcium and phosphorus concentration and parathyroid MIBI scintigraphy and US examinations were done, to evaluate each glandular function and structure. Nineteen of the 43 patients underwent total parathyroidectomy and 69 abnormal glands were removed at operation. The 69 abnormal and 4 normal glands from patients that underwent total thyroidectomy were studied by light microscopy. The results were compared and correlation was calculated to: weight, MIBI uptake and US results. RESULTS: All 43 patients had elevated serum PTH ranged from 400 to 4,075 pg/ml (1,868.0 +/- 975.9 and normal range 10-75 pg/ml). Serum calcium and phosphorus concentration were 10.13 +/- 2.02 mg/dl and 5.28 +/- 2.07 mg/dl respectively. Fifty eight of 69 glands from surgical resection were MIBI positive and 11 were negative, but their cellular composition and presentation were similar. Hyperplasic glands had increased number of all cell types considered (chief, oxyphil and clear) compared to the normal gland. Chief cell hyperplasia was the most frequent type (81 %) followed by oxyphil (9 %), clear (6 %) and adenomatous type (4 %). False negative results of 10 % to US and 4.6 % to scintigraphy were found. The correlation of gland weight and MIBI uptake were not significant (p = 0.09). The sensitivity of MIBI scintigraphy was 84 % and US was 72.5 %. CONCLUSIONS: The MIBI scintigraphy is a very sensitive tool for pre-operative localization of hyperplasic parathyroid gland and should be used as the first imaging method. The association of MIBI and US is recommended because increases the sensitivity for preoperative hyperplasic parathyroid glands identification.

Anterior vocal commissure invasion in laryngeal carcinoma diagnosis.

BACKGROUND: Laryngeal carcinoma involving anterior vocal commissure (AVC) represents a great challenge for staging and treatment. OBJECTIVES: To compare laryngoscopy and computed tomography (CT) scan efficiency in staging tumors extending to the AVC. We also analyzed the helicoidal axial CT scan accuracy in recognizing this larynx subregion invasion. MATERIAL AND METHODS: Fifty-two glottic and supraglottic laryngeal squamous cell carcinoma patients with tumoral extension to the AVC were prospectively studied from August 2001 to August 2003 at the National Cancer Institute (Rio de Janeiro, Brazil). All patients underwent videolaryngoscopic examination and direct laryngoscopy for lesion extension analysis and biopsy. After AVC helicoidal axial CT scan with sagittal and coronal 1.0 mm thick reconstruction, patients were submitted to surgical treatment. The same pathologist analyzed all surgical specimens. RESULTS: When compared with pathologic stage, clinical endoscopic classification was correct in 40.38% of cases (40% for T1, 29.41% for T2, 46.43% for T3, and 50% in T4). Helicoidal axial CT scan accuracy for AVC tumors was 75% (P = .0001), being more important for T2 (62.50%), T3 (73.91%), and T4 (88.24%) lesions. Identification of radiologic signs described as gross radiologic anterior commissure involvement (GRACI) increased radiologic image staging accuracy to over 96%. CONCLUSIONS: Endoscopic evaluation understaged tumors in all clinical stages but really T1. Helicoidal axial CT scan reformatted to 1.0 mm thick played an important role in correctly staging more advanced AVC laryngeal tumors. Radiologic signs, here identified as GRACI, may be very helpful for tomographic staging and patient treatment.

Effects of dual blockade of the renin angiotensin system in hypertensive type 2 diabetic patients with nephropathy.

AIM: To evaluate the effects of combined treatment of an ACE inhibitor and an angiotensin II receptor antagonist on parameters related to the progression of renal disease in type 2 diabetic patients. METHODS: 20 hypertensive type 2 diabetic patients with non-nephrotic proteinuria (0.5 - 3.0 g/day) and estimated creatinine clearance > or = 40 ml/min/1.73m2 were randomly assigned to be treated with perindopril 8 mg/day (Per), irbesartan 300 mg/day (Irb) or a combination of both with the same doses (Per + Irb). Each treatment phase lasting 16 weeks was preceded by a four-week washout period. Diuretics, clonidine and hydralazine were used as supplementary drugs for blood pressure control. Patients were evaluated at baseline and at the end of each treatment phase. RESULTS: 15 (3M/12F) patients completed all the phases. Use of Per, Irb and Per + Irb led to a reduction in 24-hour mean blood pressure of 6 mmHg, 4 mmHg and 4 mmHg, respectively. Changes in glomerular filtration rate were not significant at any phase. Renal plasma flow was significantly more elevated with Irb than Per. Treatment with both Irb and Per + Irb induced similar plasma renin elevation, but treatment with Per did not, suggesting escape. Plasma aldosterone was reduced only by treatment with Per + Irb (-36%, p < 0.02). Reduction in proteinuria during Per + Irb (-33%) was not significantly different from Per (-34%) or Irb (-22%). Urinary transforming growth factor beta1 (TGF-beta1) excretion was significantly reduced with both Irb (-24%, p < 0.05) and Per + Irb (-36%, p < 0.05) but not with Per (-11%, p = 0.60). CONCLUSION: Only combined therapy with irbesartan plus perindopril concurrently reduces plasma aldosterone, proteinuria and urinary TGF-beta1.

The effect of mitomycin-C on the biodistribution of 99Tcm-MDP in Balb/c mice.

Drug therapy can alter the biodistribution of radiopharmaceuticals. We studied the effect of mitomycin-C, a drug used in oncology, on the biodistribution in mice of 99Tcm-methylene diphosphonic acid (99Tcm-MDP). Three doses of mitomycin-C were administered. After the last dose, 99Tcm-MDP was injected and the animals were killed. The organs were isolated, their weight determined and the percent per gram injected dose (%ID/g) calculated. The %ID/g had increased in the pancreas, ovary, stomach, uterus, kidneys, spleen, thymus, heart, liver and lungs, but did not change significantly in thyroid, bone or brain. As a change in 99Tcm-MDP uptake by bone is not observed, a modification to bone scintigraphy is not required. As mitomycin-C treatment altered 99Tcm-MDP uptake in some organs, any hot spots should be evaluated carefully to avoid a misdiagnosis.

Assessment of the effect of vincristine on the biodistribution of 99Tcm-labelled glucoheptonic acid in female Balb/c mice.

There is evidence that the biodistribution and the pharmacokinetics of 99Tcm radiopharmaceuticals can be modified by some drugs, pathological states, irradiation and surgical procedures. Vincristine have been widely used in various chemotherapeutic protocols in oncology. We are trying to develop an animal model to assess the toxicology in different organs of compounds used as therapeutic drugs. We have studied the effect of vincristine on the distribution of 99Tcm-glucoheptonic acid (99Tcm-GHA) in female mice. After the last dose of vincristine, 99Tcm-GHA (7.4 MBq) was injected, the animals sacrificed and the percentage of radioactivity determined in the isolated organs. The percentage of activity was significantly decreased in the uterus, ovary, spleen, thymus, lymph nodes (inguinal and mesenteric), kidney and heart, but was not significantly altered in the lung, liver, pancreas, stomach, thyroid, brain and bone. Our results can be explained by the metabolic, toxic, therapeutic and immunosuppressive actions of this chemotherapeutic drug.

Labelling of the platyhelminth Dugesia tigrina with 99mtechnetium.

The study of the labelling of planaria with 99mTc shows that the incorporation of radioactivity in this platyhelminth increases with an increase in SnCl2 concentration from 0.13 to 1.3 microM, reaching a plateau in the range of 1.3-130 microM then decreasing with 1300 microM. At concentrations of 1.3 and 13 microM SnCl2, a stronger binding of 99mTc was obtained. The biological viability of the labelled planaria was not altered when the described methodology was used. The advantage of this new labelling technique is that it is possible to obtain a platyhelminth preparation labelled with a radionuclide that is very cheap, is easily available and is a gamma emitter with a photon energy of 140 keV.

The effect of vincristine on the biodistribution of technetium-99m DTPA, GHA, and DMSA in Balb/c female mice.

OBJECTIVE: Vincristine has been widely used in various chemotherapeutic protocols in oncology. The purpose of this study was to evaluate the effect of vincristine on the biodistribution of 99mTc-DMSA, 99mTc-GHA, and 99mTc-DTPA in Balb/c female mice. METHODS: Vincristine (0.03 mg, 0.3 mL) was injected into female isogenic Balb/c mice (n = 15), in 3 doses over an interval of 96 h. The 99mTc-DMSA, 99mTc-GHA, or 99mTc-DTPA (7.4 MBq) was administered after the last dose of vincristine. After 0.5 h the animals were killed rapidly. The organs (pancreas, thyroid, brain, thymus, ovary, uterus, spleen, kidney, heart, stomach, lung, liver, bone, and lymph nodes) were isolated and the radioactivity in each organ was counted in a NaI(Tl) well counter. The percentage of radioactivity (%) in each was calculated and compared with the control group. Statistical analysis was performed by Wilcoxon test (P < 0.05). RESULTS: The percentage of 99mTc-DMSA was increased in the lung, pancreas, heart, thyroid, brain, bone, and lymph nodes (inguinal and mesenteric). The percentage of 99mTc-GHA was decreased in the uterus, ovary, spleen, thymus, lymph nodes (inguinal and mesenteric), kidney, and heart. The percentage of 99mTc-DTPAwas increased in thymus, lymph nodes (inguinal and mesenteric), ovary, uterus, spleen, kidney, heart, stomach, lung, liver, and bone. CONCLUSION: The results could be explained by the metabolization, toxic effect, therapeutic, or immunosupressive action of the studied chemotherapeutic drug.

Effect of extract of medicinal plants on the labeling of blood elements with Technetium-99m and on the morphology of red blood cells: I--a study with Paullinia cupana.

Drugs can alter the labeling and the morphology of red blood cells. As Paullinia cupana is used in popular medicine, we evaluated its influence on the labeling process using technetium-99m (Tc-99m). Blood was incubated with P. cupana, stannous chloride and Tc-99m. Samples were centrifuged and plasma (P) and blood cells (BC) were separated and precipitated with trichloroacetic acid. Soluble (SF) and insoluble fractions (IF) were isolated. The morphology of the blood cells was evaluated under an optical microscope. The results showed a significant (P = 0.05) decrease in the uptake of radioactivity for the RBC (97.93 +/- 0.74 to 36.90 +/- 4.71%), in IF-P and in IF-BC due to P. cupana extract. The study of the morphology of the RBC revealed alterations in the shape of these cells. We suggest that the P. cupana effect could be explained by an inhibition of the stannous and pertechnetate ions or oxidation of the stannous ion or by damages in the plasma membrane.

Sonographic quantitative analysis of the heart in the third trimester of gestation.

The fetal heart was studied with transabdominal sonography in 40 single normal pregnancies to analyze the increase of cardiac length and width (major longitudinal and transverse diameters of the heart) during the third trimester. Relationships between the cardiac data and fetal age, femur length and biparietal diameter (BPD) were explored by allometry and linear regression analysis. The length and width of the heart could be measured reproducibly in the 4-chamber view of the heart. This study verified that the heart grows very rapidly during the third trimester (positive allometry). The linear increase of the fetal heart shows a strong and significant correlation with the increase of both femur length and BPD. This suggests that non invasive analysis of cardiac data can be useful for prenatal detection of congenital heart disease or for the assessment of gestational age.

Technetium-99m distribution into Klebsiella pneumoniae.

Bacteria labelled with radionuclide has been the subject of much investigation and has been applied in microbiological research. Technetium-99m (99mTc) may be an alternative radionuclide for the labelling of bacteria employed in various microbiological procedures. This radionuclide is easily available, is not expensive and presents important physical and biological characteristics. 99mTc-labelled bacteria are stable and their cell viability and biological properties are not modified. Study of the distribution of radioactivity in 99mTc-labelled Klebsiella pneumoniae cultures, after homogenization and differential centrifugation of the cells fractions, showed that this radionuclide was present inside the cell, mainly in a ribosomal fraction. Treatment of these fractions with enzymes and detergent revealed a high sensitivity to pronase and Triton X-100. After phenol extraction, a large percentage of radioactivity was detected in the phenol phase. Treatment of the soluble fraction with trichloroacetic acid at different temperatures showed that the concentration of 99mTc in the precipitate was lower at 100 degrees than at 4 degrees C. These results suggest that 99mTc binds mainly to the proteins in Klebsiella pneumoniae.

Conditions for labeling of Schistosoma mansoni cercaria with technetium-99m.

Study of the labeling of Schistosoma mansoni cercaria with technetium-99m (99mTc) at room temperature (25 degrees C) and 37 degrees C shows that the incorporation of radioactivity in this cercaria increases with the increase in stannous chloride concentration, reaching a constant value threshold at 130.00 microM. Strong binding of the 99mTc was obtained since the radioactivity was not washed out. The characteristic motion of the cercaria, labeled at 25 degrees C and 37 degrees C, was only modified at the concentration of 1300 microM for both temperatures, showing that the methodology here described can be applied to living structures. With this technique it is possible to obtain a cercariae suspension labeled with a radionuclide that is very inexpensive and readily available. Furthermore, it is a gamma emitter with a photon energy of 140 keV that would permit one to make scannings of the infected animals and causes less of an environmental impact and present fewer radioactive disposal problems than the long lived radionuclides.

Parathyroid glands: combination of sestamibi-99mTc scintigraphy and ultrasonography for demonstration of hyperplasic parathyroid glands

Objetivo. Determinar la frecuencia de los tipos de hiperplasia de glándulas paratiroides y la sensibilidad de la gammagrafía con sestamibi-99mTc (MIBI) y de la ultrasonografía (US) para evaluar pacientes con hiperparatiroidismo secundario (HPTS). Material y métodos. Fueron estudiados 43 pacientes con HPTS (26 mujeres y 17 hombres con edades entre 27 y 75 años). Fueron determinadas las concentraciones de hormona paratiroidea intacta (PTHi), calcio y fósforo y evaluada la acumulación total del MIBI en las paratiroides así como la US para evaluación de la estructura y función glandular. En 19 de los 43 pacientes fue realizada resección de 69 glándulas anormales. Las glándulas anormales y 4 normales fueron estudiadas por microscopía óptica. Los resultados fueron comparados y la correlación estimada en relación al peso y a la acumulación de MIBI. Resultados. El total de los 43 pacientes presentó niveles elevados de PTHi (400-4.075 pg/ml) y los niveles de calcio y fósforo fueron, de media, 10,13 ± 2,02 mg/dl y 5,28 ± 2,07 mg/dl, respectivamente. Cincuenta y ocho de las 69 glándulas resecadas fueron positivas para MIBI y 11 negativas. Sin embargo, la composición celular y su presentación fueron semejantes. Las glándulas con hiperplasia presentaron un número aumentado de todos los tipos celulares. Las células principales fueron el tipo celular que presentó hiperplasia más frecuentemente (81 %), seguidas por las células oxifílicas (9 %), las claras (6 %) y las adenomatosas (4 %). Se encontraron resultados falsos negativos en el 10 % de las US y en el 4,6 % de las gammagrafías. La correlación entre el peso glandular y la acumulación de MIBI no fue significativa (p = 0,09). La sensibilidad de la gammagrafía con MIBI fue del 84 % y del 72,5 % para la US. Conclusiones. La gammagrafía con MIBI es una herramienta de alta sensibilidad para la localización de las glándulas con hiperplasia y debería ser utilizada como primera opción de evaluación. Se recomienda la asociación de gammagrafía con MIBI y la US en función del aumento de sensibilidad total con el uso de ambas técnicas

Objective. To determine the frequency of the types of parathyroid gland hyperplasia and the sensitivity of sestamibi-99mTc (MIBI) scintigraphy and ultrasonography (US) of patients with secondary hyperparathyroidism (SHPT) due to chronic renal failure. Material and methods. We studied 43 patients with SHPT (26 females and 17 males with age range of 27-75 years). Blood tests were performed to determine intact parathyroid hormone (PTH), calcium and phosphorus concentration and parathyroid MIBI scintigraphy and US examinations were done, to evaluate each glandular function and structure. Nineteen of the 43 patients underwent total parathyroidectomy and 69 abnormal glands were removed at operation. The 69 abnormal and 4 normal glands from patients that underwent total thyroidectomy were studied by light microscopy. The results were compared and correlation was calculated to: weight, MIBI uptake and US results. Results. All 43 patients had elevated serum PTH ranged from 400 to 4,075 pg/ml (1,868.0 ± 975.9 and normal range 10-75 pg/ml). Serum calcium and phosphorus concentration were 10.13 ± 2.02 mg/dl and 5.28 ± 2.07 mg/dl respectively. Fifty eight of 69 glands from surgical resection were MIBI positive and 11 were negative, but their cellular composition and presentation were similar. Hyperplasic glands had increased number of all cell types considered (chief, oxyphil and clear) compared to the normal gland. Chief cell hyperplasia was the most frequent type (81 %) followed by oxyphil (9 %), clear (6 %) and adenomatous type (4 %). False negative results of 10 % to US and 4.6 % to scintigraphy were found. The correlation of gland weight and MIBI uptake were not significant (p = 0.09). The sensitivity of MIBI scintigraphy was 84 % and US was 72.5 %. Conclusions. The MIBI scintigraphy is a very sensitivity tool for pre-operative localization of hyperplasic parathyroid gland and should be used as the first imaging method. The association of MIBI and US is recommended because increases the sensitivity for preoperative hyperplasic parathyroid glands identification

Cintigrafia pulmonar / Pulmonary scintigraphy

Carecendo de especificidade, mas com alta sensibilidade, a cintigrafia pulmonar de perfusäo pode demonstrar áreas de déficit circulatório decorrentes do comprometimento arterial, como na embolia pulmonar (EP), nas lesöes mediastínicas com compressäo vascular etc. Entretanto, a história clínica, o exame físico e o auxílio métodos diagnósticos complementares podem conduzir, de forma mais fácil, ao diagnóstico preciso da doença. Em caso de suspeita de EP, o exame radiológico do tórax e a cintigrafia pulmonar de perfusäo podem permitir uma visäo global e quase sempre definida do quadro do paciente; tanto melhor quanto mais precoces tais exames

Labelling of the platyhelminth Dusegia tigrina with 99mTechnetium

The study of the labelling of planaria with 99mTc shows that the incorporation of radioactivity in this platyhelminth increases with an increase sin SnCl2 concentration from 0.13 to 1.3 micronM, reaching a plateau in the range of 1.3-130 micronM then decreasing with 1300 microng. At concentrations of 1.3 and 13 microngM SnCl2, a stronger binding of 99mTc was obtained. The biological viability of the labelled planaria was not altered when the described methodology was used. The advantage of this new labelling technique is that it is possible to obtain a platyhelminth preparation labelled with a radionuclide that is very cheap, is easily available and is a gamma emitter with a photon energy of 140 KeV

Marcaçäo in vitro de hemácias com tecnécio-99m: aplicaçäo clínica em cintilografia esplênica seletiva; nota técnica / \"In vitro\" labeling of red blood cells with technetium-99m: clinical application for selective splenic scintigraphy - techinical note

A cintilografia esplênica seletiva pode ser o exame de eleiçäo quando há a necessidade de se estudar especificamente o baço. Para isso, descrevemos um método simplificado para marcaçäo in vitro de hemácias com tecnécio-99m com posterior desnaturaçäo térmica. Através dessa técnica é possível obter imagem cintilográfica esplênica com um número mais reduzido de manipulaçöes, quando comparada a métodos similares