OBJECTIVE: The present study was aimed at evaluating the performance of residents trained in the reading of conventional and digital mammography images with a specific computational tool. MATERIALS AND METHODS: The training was accomplished in the Laboratory of Medical Images Qualification (QualIM - Laboratório de Qualificação de Imagens Médicas). Residents in radiology performed approximately 1,000 readings of a set of 60 images acquired from a statistical phantom (Alvim®) presenting microcalcifications and fibers with different sizes. The analysis of the residents' performance in the detection of these structures was based on statistical parameters. RESULTS: Values for detection probability were respectively 0.789 and 0.818 for conventional and digital systems. False-positive rates were 8% and 6%, and true-positive rates, 66% and 70% respectively. The total kappa value was 0.553 for readings on the negatoscope (hard-copy readings), and 0.615 on the monitor (soft-copy readings). The area under the ROC curve was 0.716 for hard-copy readings and 0.810 for soft-copy readings. CONCLUSION: The training has showed to be effective, with a positive impact on the residents' performance, representing an interesting educational tool. The results of the present study suggest that this method of training based on the reading of images from phantoms can improve the practitioners' performance in the interpretation of mammographic images.

Keywords: Digital image, Teaching & learning, Mammography, Educational tool, Soft-copy reading, Hard-copy reading

OBJECTIVE: A software called QualIM® - Qualificação de Imagens Médicas was developed for training of practitioners in the interpretation of digital mammograms classified according to BI-RADS® categories, utilizing images manipulation tools on state-of-the-art displays. MATERIALS ANDMETHODS: A Delphi 7-based system stores data resulting from mammographic findings interpretation during the training, comparing them with a golden-standard data set. The database includes computed radiography, direct radiography and digitized images. The software converts computed radiography and direct radiography images into TIFF format, preserving their original spatial and contrast resolution. During the training, the images are manipulated with the aid of the software tools (zoom, inversion, digital rulers and others). Depending on the image complexity, up to eight mammographic views, six ultrasonography images and two anatomopathological images can be displayed. RESULTS: The training was initiated in 2007 and is currently included in the radiology residency program. Based on data entered by the practitioner, the software automatically generates a BI-RADS compliant text that is compared with a database. CONCLUSION: The QualIM software is a digital educational tool aimed at assisting practitioners in the recognition of visual patterns on mammographic images as well as in the interpretation of mammograms based on the BI-RADS classification.

Keywords: Training, Digital mammography, Displays

X-ray examinations may be necessary during pregnancy for an accurate diagnosis and adequate treatment administration. In these cases, the exposure to ionizing radiation and its effects on the fetus are a major concern to the patient and to the clinician. In fact, most of these examinations are safe and do not represent a significant risk to the fetus. However, the radiologist must know the potential risks to be able to instruct all personnel involved in the care of the patient.

Keywords: Ionizing radiation, Pregnancy, Computed tomography, X-ray studies

OBJECTIVE: To make a software available for training professionals in the interpretation of mammography images on digital systems. MATERIALS AND METHODS: The software was developed in Delphi and linked to a Interbase database to store mammographic images in association with the BI-RADS® category results. Images were previously qualified and digitized using a Lumiscan 75 laser scanner. Training is done on 18 × 24 cm images displayed on a 17² commercial monitor. The software allows displaying of each breast view individually, medial-lateral oblique and cranial-caudal views, or four images simultaneously. The user selects an exam from the database and makes a diagnosis classifying the image into BI-RADS® categories. At the end of the process, the software compares the user's interpretation with the data stored in the database and than yields scores. RESULTS: The user becomes familiar with digital systems, images interpretation using BI-RADS® categories and with the quality of the image generating process regarding the detection of fibers and microcalcifications. CONCLUSION: The software is available at "Universidade Federal de São Paulo", São Paulo, Brazil, intranet and is a valuable tool for training professionals interested in digital systems.

Keywords: Data base, Mammography, Digital, Quality control

OBJECTIVE: To evaluate the precision of the absorbed radiation doses in bone marrow transplant therapy during whole body irradiation. MATERIALS AND METHODS: Two-hundred CaSO4:Dy + teflon tablets were calibrated in air and in "phantom". These tablets were randomly selected and divided in groups of five in the patients' body. The dosimetric readings were obtained using a Harshaw 4000A reader. Nine patients had their entire bodies irradiated in parallel and opposite laterals in a cobalt-60 Alcion II model, with a dose rate of 0.80 Gy/min at 80.5 cm, {(10 × 10) cm² field}. The dosimetry of this unit was performed using a Victoreen 500 dosimeter. For the determination of the mean dose at each point evaluated, the individual values of the tablets calibrated in air or "phantom" were used, resulting in a build up of 2 mm to superficialize the dose at a distance of 300 cm. RESULTS: In 70% of the patients a variation of less than 5% in the dose was obtained. In 30% of the patients this variation was less than 10%, when values obtained were compared to the values calculated at each point. A mean absorption of 14% was seen in the head, and an increase of 2% of the administered dose was seen in the lungs. In patients with latero-lateral distance greater than 35 cm the variation between the calculated doses and the measured doses reached 30% of the desired dose, without the use of compensation filters. CONCLUSION: The measured values of the absorbed doses at the various anatomic points compared to the desired doses (theoretic) presented a tolerance of ± 10%, considering the existent anatomical differences and when using the individual calibration factors of the tablets.

Keywords: Whole body irradiation, Dosimetry, Thermoluminescent dosimeters, Doses, Bone marrow transplantation

Considering the subtle findings observed in mammography images, it is relevant to know how detectability of fibers and microcalcifications can be influenced by the luminance of the viewing boxes. Our goal was to determine the influence of the luminance on the detectability of tiny simulated objects. We obtained seven images with different exposure levels using a phantom that allows statistical analysis. The results were computed using a five point scale to report the confidence levels (100 if the evaluator was sure that the object is present; 75 if likely; 50 if uncertain; 25 if not likely; zero if definitely absent). The images were analyzed by specialists using a "standard" and a specific viewing box for mammography. The detectability was compared using the Pearson chi-square test (p < 0.05). The values varied from 0.79 to 0.87. We concluded that the detectability determined from simulated objects through readings on the specific viewing boxes is higher when compared with the readings using standard viewing boxes.

Keywords: View box, Quality control, Mammography, Luminance, Illuminators, Fluorescent tube

OBJECTIVE: To develop procedures to ensure consistency of printing quality of digital images, by means of hardcopy quantitative analysis based on a standard image. MATERIALS AND METHODS: Characteristics of mammography DI-ML and general purpose DI-HL films were studied through the QC-Test utilizing different processing techniques in a FujiFilm^®-DryPix4000 printer. A software was developed for sensitometric evaluation, generating a digital image including a gray scale and a bar pattern to evaluate contrast and spatial resolution. RESULTS: Mammography films showed maximum optical density of 4.11 and general purpose films, 3.22. The digital image was developed with a 33-step wedge scale and a high-contrast bar pattern (1 to 30 lp/cm) for spatial resolution evaluation. CONCLUSION: Mammographic films presented higher values for maximum optical density and contrast resolution as compared with general purpose films. The utilized digital processing technique could only change the image pixels matrix values and did not affect the printing standard. The proposed digital image standard allows greater control of the relationship between pixels values and optical density obtained in the analysis of films quality and printing systems.

Keywords: Hardcopy; Quality control; Contrast sensitivity; Mammography.

OBJECTIVE: To evaluate the necessity of the non contrast-enhanced phase in abdominal computed tomography scans. MATERIALS AND METHODS: A retrospective, cross-sectional, observational study was developed, evaluating 244 consecutive abdominal computed tomography scans both with and without contrast injection. Initially, the contrast-enhanced images were analyzed (first analysis). Subsequently, the observers had access to the non-contrast-enhanced images for a second analysis. The primary and secondary diagnoses were established as a function of the clinical indications for each study (such as tumor staging, acute abdomen, investigation for abdominal collection and hepatocellular carcinoma, among others). Finally, the changes in the diagnoses resulting from the addition of the non-contrast-enhanced phase were evaluated. RESULTS: Only one (0.4%; p > 0.999; non-statistically significant) out of the 244 reviewed cases had the diagnosis changed after the reading of non-contrast-enhanced images. As the secondary diagnoses are considered, 35 (14%) cases presented changes after the second analysis, as follows: nephrolithiasis (10%), steatosis (3%), adrenal nodule (0.7%) and cholelithiasis (0.3%). CONCLUSION: For the clinical indications of tumor staging, acute abdomen, investigation of abdominal collections and hepatocellular carcinoma, the non-contrast-enhanced phase can be excluded from abdominal computed tomography studies with no significant impact on the diagnosis.

Keywords: Computed tomography; Ionizing radiation; Abdomen; Contrast media.

OBJECTIVE: To assess the reduction of estimated radiation dose in abdominal computed tomography following the implementation of new scan protocols on the basis of clinical suspicion and of adjusted images acquisition parameters. MATERIALS AND METHODS: Retrospective and prospective review of reports on radiation dose from abdominal CT scans performed three months before (group A - 551 studies) and three months after (group B - 788 studies) implementation of new scan protocols proposed as a function of clinical indications. Also, the images acquisition parameters were adjusted to reduce the radiation dose at each scan phase. The groups were compared for mean number of acquisition phases, mean CTDI_vol per phase, mean DLP per phase, and mean DLP per scan. RESULTS: A significant reduction was observed for group B as regards all the analyzed aspects, as follows: 33.9%, 25.0%, 27.0% and 52.5%, respectively for number of acquisition phases, CTDI_vol per phase, DLP per phase and DLP per scan (p < 0.001). CONCLUSION: The rational use of abdominal computed tomography scan phases based on the clinical suspicion in conjunction with the adjusted images acquisition parameters allows for a 50% reduction in the radiation dose from abdominal computed tomography scans.

Keywords: Computed tomography; Abdomen; Contrast media; Radiation dose; Radiation protection.

OBJECTIVE: To study the influence that the scan percentage tool used in partial k-space acquisition has on the quality of images obtained with magnetic resonance imaging equipment. MATERIALS AND METHODS: A Philips 1.5 T magnetic resonance imaging scanner was used in order to obtain phantom images for quality control tests and images of the knee of an adult male. RESULTS: There were no significant variations in the uniformity and signal-to-noise ratios with the phantom images. However, analysis of the high-contrast spatial resolution revealed significant degradation when scan percentages of 70% and 85% were used in the acquisition of T1- and T2-weighted images, respectively. There was significant degradation when a scan percentage of 25% was used in T1- and T2-weighted in vivo images (p < 0.01 for both). CONCLUSION: The use of tools that limit the k-space is not recommended without knowledge of their effect on image quality.

Keywords: Magnetic resonance imaging; K-space; Quality control; In vivo magnetic resonance imaging.