OBJECTIVE: To evaluate an alternative brachytherapy technique for uterine cervix cancer involving the distal vagina, without increasing the risk of toxicity. MATERIALS AND METHODS: Theoretical study comparing three different high-dose rate intracavitary brachytherapy applicators: intrauterine tandem and vaginal cylinder (TC); tandem/ring applicator combined with vaginal cylinder (TR+C); and a virtual applicator combining both the tandem/ring and vaginal cylinder in a single device (TRC). Prescribed doses were 7 Gy at point A, and 5 Gy on the surface or at a 5 mm depth of the vaginal mucosa. Doses delivered to the rectum, bladder and sigmoid colon were kept below the tolerance limits. Volumes covered by the isodoses, respectively, 50% (V50), 100% (V100), 150% (V150) and 200% (V200) were compared. RESULTS: Both the combined TR+C and TRC presented a better dose distribution as compared with the TC applicator. The TR+C dose distribution was similar to the TRC dose, with V150 and V200 being about 50% higher for TR+C (within the cylinder). CONCLUSION: Combined TR+C in a two-time single application may represent an alternative therapy technique for patients affected by uterine cervix cancer involving the distal vagina.

Keywords: Cervical cancer, Radiotherapy, Intracavitary brachytherapy, Dosimetry

OBJECTIVE: To assess the role of proton magnetic resonance spectroscopy and dynamic contrast-enhanced magnetic resonance imaging in the differentiation between malignant and benign musculoskeletal tumors. MATERIALS AND METHODS: Fifty-five patients with musculoskeletal tumors (27 malignant and 28 benign) were studied. The examinations were performed in a 1.5 T magnetic resonance scanner with standard protocol, and single voxel proton magnetic resonance spectroscopy with 135 msec echo time. The dynamic contrast study was performed using T1-weighted gradient-echo sequence after intravenous gadolinium injection. Timesignal intensity curves and slope values were calculated. The statistical analysis was performed with the Levene's test, followed by a Student's t-test, besides the Pearson's chi-squared and Fischer's exact tests. RESULTS: Proton magnetic resonance spectroscopy sensitivity, specificity and accuracy were, respectively, 87.5%, 92.3% and 90.9% (p < 0.0001). Statistically significant difference was observed in the slope (%/min) between benign (mean, 27.5%/min) and malignant (mean, 110.9%/min) lesions (p < 0.0001). CONCLUSION: The time-intensity curve and slope values using dynamic-enhanced perfusion magnetic resonance imaging in association with the presence of choline peak demonstrated by single voxel magnetic resonance spectroscopy study are useful in the differentiation between malignant and benign musculoskeletal tumors.

Keywords: Proton magnetic resonance spectroscopy, Perfusion magnetic resonance imaging, Magnetic resonance imaging

OBJECTIVE: To demonstrate the effectiveness and practical outcomes of percutaneous ethanol sclerotherapy in patients with symptomatic simple renal cysts. MATERIALS AND METHODS: The authors reviewed the outcomes of ten patients (eight men and two women) in the age range between 28 and 72 years (mean, 55 years) submitted to at least two procedures of percutaneous sclerotherapy for symptomatic simple renal cysts. Main presentation was refractory flank pain in all patients, seven of them with some degree of hydronephrosis because of the parapyelic localization of the cyst. The aspirated volume ranged from 20 to 1300 ml (mean, 200 ml). The mean follow-up period following the procedure was of seven months. Two patients had ultrasoud-guided sclerotherapy, and eight, computed tomography-guided sclerotherapy. The hospital stay period ranged between 24 and 72 hours. Complete success corresponded to total cyst regression, and partial success corresponded to recurrence of less than half the original cyst volume. RESULTS: Complete cyst ablation was achieved in seven patients and partial resolution in three. No complication was observed and the therapy was well tolerated by all of the patients. CONCLUSION: Percutaneous ethanol sclerotherapy of symptomatic simple renal cysts is a safe, effective and minimally invasive procedure, with results similar to the ones reported by other studies.

Keywords: Kidney diseases, Sclerotherapy, Ethanol

OBJECTIVE: To quantify neointimal hyperplasia in iliac arteries after stent implantation, correlating clinical, arterial factors and stent material. MATERIALS AND METHODS: In the period from June/2003 to August/ 2005, 60 patients were submitted to percutaneous transluminal angioplasty and stenting. Among these patients, 30 were followed-up with intravascular ultrasonography. Data were analyzed in a laboratory of quantitative analysis by means of a specific software. RESULTS: Sixteen (53.3%) patients were men, and 14 (46.7%), women, and the mean age was 60.3 years. Arterial hypertension was observed in 22 patients (73.3%), smoking in 18 (62.1%), hyperlipidemia in 20 (66.7%), and diabetes in 9 (30%). A total of 20 nitinol stents (66.7%) and 10 stainless steel stents (33.3%) were implanted. Four patients were classified as TASC A (13.3%), 15 TASC B (50%) and 11 TASC C (36.7%). The neointimal hyperplasia volume ranged from 49.02 mm³ to 112.87 mm³ (mean, 80.33 mm³). The rate of intrastent obstruction ranged from 18% to 47% (mean, 27.4%). The clinical outcomes achieved with stenting were sustained through the follow-up. CONCLUSION: Neointimal hyperplasia is a common finding after percutaneous transluminal angioplasty and stenting, but in the present study the stenosis rate was never higher than 50%. There was no statistically significant difference in intrastent stenosis rates in relation to stents materials, clinical and arterial risk factors.

Keywords: Stent, Iliac artery, Interventional ultrasonography, Hyperplasia

OBJECTIVE: The main purpose of the present study is to evaluate the accuracy of ultrasonography (BI-RADS) in the diagnosis of breast cancer whereas the additional specific objectives are to describe the frequency of different sonographic findings and evaluating interobserver agreement. MATERIALS AND METHODS: Images of 110 patients who had been referred for biopsy with previous diagnosis of breast nodules were independently reviewed by two specialists according to the BI-RADS classification. Histological findings were utilized as a gold-standard. The accuracy of findings was determined. The chi-squared test for categorical variables was utilized in the analysis of the differences resulting from the groups comparison, and the interobserver agreement was calculated with kappa () statistics. RESULTS: Among 110 breast masses evaluated by ultrasonography, 76 (69%) were benign and 34 (30.9%) were malignant. According to the radiologists, the sensitivity ranged from 70.5% to 82.3%, negative predictive value, from 81.1% to 87.5%, positive predictive value, from 42.1% to 45.1%, specificity from 56.58% to 55.2%, and accuracy from 60.9% to 63.6%. The global interobserver agreement was considered as moderate ( = 0.50). CONCLUSION: The fourth edition of BI-RADS provides radiologists with an accurate clinical decision support system for the diagnosis and management of breast disease.

Keywords: Breast cancer, Ultrasonography, BI-RADS, Anatomopathological, Accuracy

OBJECTIVE: The present study was aimed at evaluating the role played by spectral Doppler as a method to measure the vascular resistance index in the differentiation between benign and malignant breast lesions. MATERIALS AND METHODS: Nineteen malignant and 18 benign lesions histologically diagnosed had their vascularization previously analyzed through the resistance index. RESULTS: A statistically significant difference (p < 0.001) was observed between the mean values of resistance index for benign and malignant lesions (respectively 0.62x 0.80) in nodular breast lesions greater than 1 cm. A resistance index 0.69 was highly associated with malignant lesions, with 84.2% sensitivity, 88.9% specificity, false-positive rate of 11.1%, and false-negative rate of 15.8%. CONCLUSION: The analysis of vascular resistance index combined with findings on grayscale sonographic images can be of great assistance in the assessment of nodular breast lesions greater than 1 cm, with high sensitivity and specificity.

Keywords: Breast, Breast lesions, Ultrasonography, Doppler, Resistance index

OBJECTIVE: Comparative study of receptiveness (cooperation) and sensitivity of upper gastrointestinal series and intraabdominal esophagus ultrasonography in patients with suspicion of gastroesophageal reflux. MATERIALS AND METHODS: The present study included 42 pediatric patients (26 male, with mean age of 33.64 ± 34.33 months, and 16 female, with mean age of 31.02 ± 35.56 months) with suspicion of gastroesophageal reflux, who were initially submitted to upper gastrointestinal series and subsequently to intraabdominal esophagus ultrasonography. RESULTS: The statistical comparative analysis covering sexes and ages suggests no evidence of association with cooperation, both for the upper gastrointestinal series and the intraabdominal esophagus ultrasonography. However, in the classification of the patients' cooperation, the technique of upper gastrointestinal series presented less than 50% of cooperation, while 80.49% of patients cooperated in the intraabdominal esophagus ultrasonography examinations. As regards the methods sensitivity for the diagnosis of gastroesophageal reflux, the technique of intraabdominal esophagus ultrasonography was significantly superior (85.7%) to the upper gastrointestinal series (47.6%). CONCLUSION: The present study suggests that an intraabdominal esophagus ultrasonography should be performed even if gastroesophageal reflux even if it is not detected at the upper gastrointestinal series.

Keywords: Gastroesophageal reflux, Intraabdominal esophagus, Ultrasonography, Contrast-enhanced study

OBJECTIVE: The PENELOPE code was utilized to simulate irradiation geometries where heterogeneities are present and to simulate a photon beam behavior under these conditions. MATERIALS AND METHODS: For the homogeneous case, the ionizing radiation behavior was simulated only with water, and different materials were introduced to simulate heterogeneous conditions. Cubic geometries were utilized for the homogeneous phantoms, and parallelepiped-shaped geometries for the heterogeneities with the following composition: bone and lung tissue simulators, as recommended by the International Commission on Radiological Protection, and titanium, aluminum and silver. Input parameters were defined as follows: energy and type of source, 6 MV photons; source-surface distance=100 cm; and radiation field of 10x 10 cm². RESULTS: Percentage depth-dose curves were obtained for all the cases. As result, it was observed that for high electronic density materials, such as silver, the absorbed dose is higher than the absorbed dose in the homogeneous phantom, and for the lung tissue simulator, it is lower. CONCLUSION: Results clearly demonstrate the relevant role of heterogeneities in the treatment planning system algorithms utilized in the calculation of dose distribution in patients, increasing the accuracy of the dose delivered to the tumor and avoiding unnecessary irradiation of healthy tissues.

Keywords: Radiotherapy, Monte Carlo, PENELOPE, Heterogeneities, Depth-dose distribution

OBJECTIVE: To assess the performance of radionuclide calibrators in 55 Brazilian nuclear medicine services in the measurement of 99Tc m radiopharmaceutical activity. Proficiency tests were applied to data sets with 63 results originated from the comparison program developed by Laboratório Nacional de Metrologia das Radiações Ionizantes of Instituto de Radioproteção e Dosimetria. MATERIALS AND METHODS: The calibrators' performance was evaluated in compliance with the acceptance criterion of ±10% accuracy required by the Brazilian standards and also the criteria established by the ISO/IEC Guide 43-1, and classified as either "acceptable" or "non-acceptable". The samples of 99Tc m utilized in the comparison were supplied by some of the participants and calibrated at Laboratório Nacional de Metrologia das Radiações Ionizantes for determining the activity reference value. RESULTS: The present study utilizing 99Tc m has shown that 82.5% of the calibrators were considered as acceptable according to the Brazilian standards, while by the criteria established by ISO/IEC 43-1, 81.0% were considered as acceptable. On the other hand, radionuclide calibrators with Geiger-Müller detectors presented unsatisfactory performance when compared with calibrators with ionization chambers. CONCLUSION: The performance evaluation based on the ISO/IEC 43-1 criteria, which are applied to analytical laboratories, in spite of being more restrictive, has demonstrated to be quite consistent with the accuracy criterion established by the Brazilian standard.

Keywords: Proficiency test, Radionuclide calibrator, Nuclear medicine, 99Tc m

Thyroid ophthalmopathy is an autoimmune orbital disorder closely associated with Graves' disease, although both conditions may also occur isolatedly. Thyroid ophthalmopathy may precede, coincide or follow the thyroid dysfunction onset and may rarely occur in euthyroid and hypothyroid patients. The extraocular muscles are most frequently involved and become enlarged resulting in ophthalmoplegia and proptosis. Other relevant signs include palpebral retraction, conjuctival hyperemia and periorbitary edema. Visual loss may occur in association with compressive optic neuropathy at the orbital apex. Thyroid ophthalmopathy is characterized by inflammation, congestion, hypertrophy and fibrosis involving fat and the orbital muscles. The disease activity is divided into two phases: an acute or inflammatory phase and a second one corresponding to an inactive phase associated with fibrotic changes and fat infiltration of the retrobulbar tissues. The diagnosis is based on clinical findings and imaging methods are indicated in case of doubt or suspicion of optic neuropathy. Computed tomography and magnetic resonance imaging can confirm the diagnosis, allowing the evaluation of the critical region of the orbital apex. Magnetic resonance imaging is the method of choice considering the superior tissue contrast resolution, besides the capacity of evaluating the disease activity by means of long TR sequences and detecting inflammatory changes, with a relevant role in a timely therapeutic planning, which may improve the prognosis.

Keywords: Thyroid ophthalmopathy, Extraocular muscles, Magnetic resonance imaging, Computed tomography

Erdheim-Chester disease is a rare non-Langerhans cell histiocytosis of unknown etiology, affecting multiple organ system, involving bones, central nervous system, eyes, lungs, mediastinum, kidneys and retroperitoneum. The authors report two cases that progressed with the typical presentation of the disease. Radiological findings were in agreement with literature and guided the diagnosis, confirmed by immunohistochemistry.

Keywords: Erdheim-Chester disease, Radiography, Computed tomography

Hepatic hemangioma is frequently asymptomatic, and bleeding is rare, even in cases of large lesions. The authors report the case of a 31-year-old female patient presenting with acute abdominal pain, whose imaging studies have demonstrated hematoma in the left hepatic lobe associated with hemoperitoneum. The patient was submitted to left hepatectomy, with a final histopathological diagnosis of cavernous hemangioma.

Keywords: Hepatic hemangioma, Hemoperitoneum, Computed tomography, Acute abdomen