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PURPOSE: To provide a guideline curriculum related to Artificial Intelligence (AI), for the education and training of European Medical Physicists (MPs). MATERIALS AND METHODS: The proposed curriculum consists of two levels: Basic (introducing MPs to the pillars of knowledge, development and applications of AI, in the context of medical imaging and radiation therapy) and Advanced. Both are common to the subspecialties (diagnostic and interventional radiology, nuclear medicine, and radiation oncology). The learning outcomes of the training are presented as knowledge, skills and competences (KSC approach). RESULTS: For the Basic section, KSCs were stratified in four subsections: (1) Medical imaging analysis and AI Basics; (2) Implementation of AI applications in clinical practice; (3) Big data and enterprise imaging, and (4) Quality, Regulatory and Ethical Issues of AI processes. For the Advanced section instead, a common block was proposed to be further elaborated by each subspecialty core curriculum. The learning outcomes were also translated into a syllabus of a more traditional format, including practical applications. CONCLUSIONS: This AI curriculum is the first attempt to create a guideline expanding the current educational framework for Medical Physicists in Europe. It should be considered as a document to top the sub-specialties' curriculums and adapted by national training and regulatory bodies. The proposed educational program can be implemented via the European School of Medical Physics Expert (ESMPE) course modules and - to some extent - also by the national competent EFOMP organizations, to reach widely the medical physicist community in Europe.
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Inteligencia Artificial , Medicina Nuclear , Curriculum , Europa (Continente) , Física Sanitaria , HumanosRESUMEN
PURPOSE: This study investigated the benefits of implementing a cluster analysis technique to extract relevant information from a computed tomography (CT) dose registry archive. METHODS: A CT patient dose database consisting of about 12,000 examinations and 29,000 single scans collected from three CT systems was interrogated. The database was divided into six subsets according to the equipment and the reference phantoms in the definition of the dose indicators. Hierarchical (single, average, and complete linkage, Ward) and not hierarchical (K-means) clustering methods were implemented using R software. The suitable number of clusters for each CT system was determined by analysing the dendrogram, the within clusters sum of squares, and the cluster content. Summary statistics were produced for each cluster, and the outliers of the dose indicator distribution were investigated. RESULTS: Ward clustering identified the most common combinations of scanning parameters for each group. The optimal number of clusters for each CT equipment system ranged from 5 to 15. The main diagnostic applications were then extracted from each cluster. Outlier analysis of the dose indicator distribution of each cluster revealed potential improper settings that resulted in increased patient dose. CONCLUSIONS: Clustering methods applied to CT patient dose archives provide a quick and effective overview of the main combinations of currently used exposure parameters and the consequences for dose indicator distributions, also when protocol labels and/or study descriptions are not homogeneous.
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Análisis por Conglomerados , Dosis de Radiación , Tomografía Computarizada por Rayos X , Aprendizaje Automático no Supervisado , Minería de Datos/métodos , Bases de Datos Factuales , Humanos , Fantasmas de Imagen , Sistema de Registros , Programas InformáticosRESUMEN
Dental CT dose evaluations are commonly performed using thermoluminescent dosimeters (TLD) inside anthropomorphic phantoms. Radiochromic films with good sensitivity in the X-ray diagnostic field have recently been developed and are commercially available as GAFCHROMIC XR-QA. There are potential advantages in the use of radiochromic films such as a more comprehensive dosimetry thanks to the adjustable size of the film samples. The purpose of this study was to investigate the feasibility of using radiochromic films for dental CT dose evaluations. Film samples were cut with a width of 5mm and a length of 25 mm (strips), the same size as the Alderson Rando anthropomorphic phantom holes used in this study. Dental CT dose measurements were performed using simultaneously both TLD and radiochromic strips in the same phantom sites. Two equipment types were considered for dental CT examinations: a 16 slice CT and a cone beam CT. Organ equivalent doses were then obtained averaging the measurements from the sites of the same organ and effective doses were calculated using ICRP 103 weighting factors. The entire procedure was repeated four times for each CT in order to compare also the repeatability of the two dosimeter types. A linear correlation was found between the absorbed dose evaluated with radiochromic films and with TLD, with slopes of 0.930 and 0.944 (correlation r>0.99). The maximum difference between the two dosimeter's measurements was 25%, whereas the average difference was 7%. The measurement repeatability was comparable for the two dosimeters at cumulative doses above 15 mGy (estimated uncertainty at 1 sigma level of about 5%), whereas below this threshold radiochromic films show a greater dispersion of data, of about 10% at 1 sigma level. We obtained, using respectively Gafchromic and TLD measurements, effective dose values of 107 µSv and 117 µSv (i.e. difference of 8.6%) for the cone beam CT and of 523 µSv and 562 µSv (i.e. difference of 7%) for the multislice CT. This study demonstrates the feasibility of radiochromic films for dental CT dosimetry, pointing out a good agreement with the results obtained using TLD, with potential advantages and the chance of a more extensive dose investigation.
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Odontología , Dosimetría por Película/métodos , Tomografía Computarizada por Rayos X , Estudios de Factibilidad , Humanos , Fantasmas de Imagen , Dosis de RadiaciónRESUMEN
OBJECTIVE: This study aims to investigate the consequences on dose and image quality of the choices of different combinations of NI and adaptive statistical iterative reconstruction (ASIR) percentage, the image quality parameters of GE CT equipment. METHODS: An anthropomorphic phantom was used to simulate the chest and upper abdomen of a standard weight patient. Images were acquired with tube current modulation and different values of noise index, in the range 10-22 for a slice thickness of 5mm and a tube voltage of 120 kV. For each selected noise index, several image series were reconstructed using different percentages of ASIR (0, 40, 50, 60, 70, 100). Quantitative noise was assessed at different phantom locations. Computed tomography dose index (CTDI) and dose length products (DLP) were recorded. Three radiologists reviewed the images in a blinded and randomized manner and assessed the subjective image quality by comparing the image series with the one acquired with the reference protocol (noise index 14, ASIR 40%). The perceived noise, contrast, edge sharpness and overall quality were graded on a scale from -2 (much worse) to +2 (much better). RESULTS: A repeatable trend of noise reduction versus the percentage of ASIR was observed for different noise levels and phantom locations. The different combinations of noise index and percentage of ASIR to obtain a desired dose reduction were assessed. The subjective image quality evaluation evidenced a possible dose reduction between 24 and 40% as a consequence of an increment of ASIR percentage to 50 or 70%, respectively. CONCLUSION: These results highlighted that the same patient dose reduction can be obtained with several combinations of noise index and percentages of ASIR, providing a model with which to choose these acquisition parameters in future optimization studies, with the aim of reducing patient dose by maintaining image quality in diagnostic levels.
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Algoritmos , Antropometría/instrumentación , Fantasmas de Imagen , Interpretación de Imagen Radiográfica Asistida por Computador/métodos , Tomografía Computarizada por Rayos X/instrumentación , Tomografía Computarizada por Rayos X/métodos , Diseño de Equipo , Análisis de Falla de Equipo , Humanos , Reproducibilidad de los Resultados , Sensibilidad y EspecificidadRESUMEN
Gafchromic XR-QA films were developed for patient dosimetry in diagnostic radiology. A possible application of these films is the measurement of doses in computed tomography. In this study a method to evaluate the CTDI using Gafchromic XR-QA film and a flatbed scanner was developed and tested. Film samples were cut to dimensions of 6 x 170 mm2 in order to have an integration area similar to that of a pencil ionization chamber, with the possibility of changing the integration length. Prior to exposing these films to a computed tomography beam, the angular dependence of the film dose response was investigated by exposing film strips to a static x-ray beam at different angles in the range 0 degrees-180 degrees. A difference of 49% was found between the response with the axis beam parallel to the film surface (90 degrees) and with the axis beam perpendicular (0 degrees and 180 degrees). Integrating over a 360 degrees exposure like the one in computed tomography, a difference of less than 2% was estimated, which is comparable with the measurement error obtainable with XR-QA film. A calibration with a CT beam in the scout mode was performed and film strips were then exposed to single axial scans and to helical scans both in air and in phantoms. Two different types of flatbed scanners were used to read the film samples, a Microtek ScanMaker 9800XL scanner and an Epson Expression 10000 XL scanner, and the accuracy of the results were compared. For beam collimations above 10 mm differences between CTDI measured by film and CTDI measured by ionization chamber below 9% were found for the Epson scanner, with an average estimated error at 1 sigma level of 5%. For the Microtek scanner and for the same film samples, differences below 11% with an average error at 1 sigma level of 8% were founded. The 1 sigma uncertainty of the measured CTDI was provided by the method for each measurement, and it was shown that about the 95% of the differences between the CTDI measurements with radiochromic films and with the ionization chamber were below the estimated 2 sigma uncertainty, for both scanners. After an accurate calibration procedure and the consideration of the uncertainty associated with the measurement, Gafchromic XR-QA films can be used to evaluate the CTDI.
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Dosimetría por Película/instrumentación , Tomografía Computarizada por Rayos X/instrumentación , Pantallas Intensificadoras de Rayos X , Diseño Asistido por Computadora , Diseño de Equipo , Análisis de Falla de Equipo , Dosis de Radiación , Reproducibilidad de los Resultados , Sensibilidad y EspecificidadRESUMEN
The purpose of this study was to evaluate the consequences of different choices of acquisition parameters on the actual image noise and on the patient dose with an automatic tube current modulation system. The CT investigated was a GE Lightspeed 16-slice and an anthropomorphic phantom was used to simulate the patient. Several acquisitions were made varying noise index (NI), kilovoltage and pitch values. Tube current values were compared for the different acquisitions. Patient dose was evaluated in terms of volumetric computed tomography dose index (CTDI(vol)) and also as effective dose. The noise actually present in the images was analyzed by a region of interest analysis considering representatively phantom sections in the regions of the shoulders, of the lungs and of the abdomen. The obtained results generally evidenced a good agreement between the noise index and the measured noise for the abdomen sections, whereas for the shoulders and the lungs sections the measured noise was respectively greater and lower of the NI. Varying the kV the automatic current modulation system provided images with a substantially constancy of the actual noise and of the patient dose. An increase of the pitch generally decreased the patient dose, whereas the noise was slightly greater for the lowest pitch and almost constant for the other pitch values. This study outlines some important relationships between an automatic tube current modulation system and other CT acquisition parameters, providing useful informations for the choice requested by radiologists in the task of optimization of the CT acquisition protocols. Unless there are other considerations in place, pixel pitches below 1.375 should be avoided, and kVp settings can be changed with no real impact on dose or image noise.
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Carga Corporal (Radioterapia) , Dosis de Radiación , Intensificación de Imagen Radiográfica/instrumentación , Intensificación de Imagen Radiográfica/métodos , Tomografía Computarizada por Rayos X/instrumentación , Tomografía Computarizada por Rayos X/métodos , Diseño de Equipo , Análisis de Falla de Equipo , Humanos , Fantasmas de Imagen , Radiometría , Rayos XRESUMEN
PURPOSE: The purpose of this work was to evaluate the statistical distribution of patient dose for different examinations by using the data stored in a DICOM image archive of a direct digital radiography system. MATERIALS AND METHODS: An automatic procedure to extract dose data and exposure parameters from the image archives was implemented. During a 4.5-month period, 8,292 images were collected. Exposure parameters and the air kerma area product (P (KA)) stored in the image DICOM header were examined for each image. The entrance surface air kerma (K (a,e)), a quantity comparable to the current diagnostic reference levels (DRL), was estimated considering the P (KA) and the geometric parameters of each examination. RESULTS: P (KA) and K (a,e ) distributions showed highly variable values. The obtained K (a,e ) values were substantially lower than the DRL. DRL were more than six times the mean value of K (a,e ) distribution for the abdomen anteroposterior (AP) and lumbar spine lateral (LAT) projections, whereas the ratio was equal to 2.7 for posteroanterior (PA) chest examinations. CONCLUSIONS: The method adopted proved to be effective for characterising the dose of each examination by means of the statistical analysis of the dose quantities over extensive samples. The dose values obtained and the comparison with the DRL showed that this radiographic device allows substantial dose savings compared with estimations made for nondigital or for phosphor-based systems.
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Dosis de Radiación , Intensificación de Imagen Radiográfica , Distribuciones Estadísticas , HumanosRESUMEN
PURPOSE: The purpose of this study was to evaluate the radiation dose to patients during radiological contrast studies performed after vertical banded gastroplasty (VBG) or Roux-en-Y gastric bypass (RYGBP) surgery in patients with morbid obesity. MATERIALS AND METHODS: Dose evaluations were performed on a sample of 39 patients (32 women and 7 men) with a mean weight of 117 kg (range 68-175 kg) and a mean body mass index (BMI) of 43.7 (range 22.2-54.9). Between the second and seventh postoperative day, patients underwent radiological follow-up after oral administration of approximately 70 ml of water-soluble iodinated contrast material (Gastrografin) and images acquired in anteroposterior, right and left oblique projections with the patient upright and then supine. Exposure conditions, dose-area product (DAP) and entrance skin dose (ESD) were recorded for each procedure. On the basis of these data, the effective dose (ED) was calculated using simulation software based on the Monte Carlo method for determining the absorbed dose to organs. To assess the optimal exposure conditions and the dose contributions of fluoroscopy and radiography, the effective dose rates were also evaluated using Plexiglas phantoms of different thickness to simulate different patient sizes. RESULTS: The phantom measurements showed a fourfold dose increase when passing from normal-sized patients to obese patients. Mean DAP value obtained from in-vivo measurements was 70 Gy cm(2) (range 17-147 Gy cm(2)), and mean effective dose was 21 mSv (range 5-45 mSv). CONCLUSIONS: When performing radiological contrast studies in patients with morbid obesity, every possible precaution should be taken to minimise patient dose. Special care should be taken to evaluate justification of the radiological procedure.
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Medios de Contraste , Derivación Gástrica , Gastroplastia , Obesidad Mórbida/diagnóstico por imagen , Obesidad Mórbida/cirugía , Dosis de Radiación , Adolescente , Adulto , Femenino , Humanos , Masculino , Persona de Mediana Edad , Radiografía , Adulto JovenRESUMEN
PURPOSE: This study was undertaken to evaluate patient dose in paediatric liver transplant recipients treated by percutaneous biliary drainage and bilioplasty procedures. MATERIALS AND METHODS: Effective dose rates and entrance skin-dose (ESD) rates per minute of fluoroscopy were measured by using a plexiglas phantom (thickness 10 cm) simulating the patient and by varying the exposure parameters (type of pulsed fluoroscopy, image intensifier diameter, presence of diaphragms) to identify the technique delivering the lowest patient dose. In vivo measurements were performed during three interventional procedures. RESULTS: The effective dose rate proved to be lowest for a particular type of pulsed fluoroscopy, with maximum magnification and with field-limiting diaphragms. The in vivo measurements showed a maximum ESD value of around 50 MGY (the threshold for transient erythema is 2,000 MGY, ICRP 60). The effective dose values were in the range of 0.9-1.5 MSV. CONCLUSIONS: We established exposure parameters providing the desired image quality with the lowest dose for the equipment used and for a specific type of interventional procedure. The measured ESD values allow us to exclude the risk of deterministic effects on the skin. The effective dose values and considerations regarding the likelihood of radiation-induced cancer led to the conclusion that the radiological risk for the patient is largely justified by the benefits of these kinds of procedure.
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Enfermedades de los Conductos Biliares/terapia , Conductos Biliares/cirugía , Procedimientos Quirúrgicos del Sistema Biliar/métodos , Drenaje/métodos , Trasplante de Hígado , Enfermedades de los Conductos Biliares/diagnóstico por imagen , Enfermedades de los Conductos Biliares/etiología , Cateterismo , Preescolar , Colangiografía , Colangiopancreatografia Retrógrada Endoscópica , Femenino , Fluoroscopía , Humanos , Lactante , Masculino , Dosis de Radiación , Traumatismos por Radiación/prevención & control , Monitoreo de Radiación/métodos , Radiografía Intervencional , Estudios RetrospectivosRESUMEN
PURPOSE: The purpose of this paper is to describe the automation of quality control procedures on photo-stimulable imaging plates by means of an image-processing tool providing automatic reading of the images and automatic calculation of the quality parameters monitored. MATERIALS AND METHODS: Quality-control procedures were performed according to the main available guidelines. The quality assurance programme was applied to several Kodak and Philips devices in four radiological departments. The automatic image-processing tool was developed using public domain software (Java-based ImageJ software) and contains both reading and computation procedures. RESULTS: The quality checks and algorithms described were successfully applied, proving useful for identification of defective plates and for implementation of the quality assurance programme. The use of automation allowed significant savings in the time required for quality checks. CONCLUSIONS: Completely automated image reading allows substantial economic and human resources savings, as it eliminates much of the transfer, reproduction, processing and filing procedures.
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Garantía de la Calidad de Atención de Salud , Control de Calidad , Interpretación de Imagen Radiográfica Asistida por Computador , Algoritmos , Análisis Costo-Beneficio , Humanos , Procesamiento de Imagen Asistido por Computador/economía , Procesamiento de Imagen Asistido por Computador/métodos , Italia , Guías de Práctica Clínica como Asunto , Garantía de la Calidad de Atención de Salud/economíaRESUMEN
Gafchromic XR-R films are a useful tool to evaluate entrance skin dose in interventional radiology. Another dosimetric quantity of interest in diagnostic and interventional radiology is the dose area product (DAP). In this study, a method to evaluate DAP using Gafchromic XR-R films and a flat-bed scanner was developed and tested. Film samples were exposed to an x-ray beam of 80 kVp over a dose range of 0-10 Gy. DAP measurements with films were obtained from the digitalization of a film sample positioned over the x-ray beam window during the exposure. DAP values obtained with this method were compared for 23 cardiological interventional procedures with DAP values displayed by the equipment. The overall one-sigma dose measurement uncertainty depended on the absorbed dose, with values below 6% for doses above 1 Gy. A maximum discrepancy of 16% was found, which is of the order of the differences in the DAP measurements that may occur with different calibration procedures. Based on the results presented, after an accurate calibration procedure and a thorough inspection of the relationship between the actual dose and the direct measured quantity (net optical density or net pixel value variation), Gafchromic XR-R films can be used to assess the DAP.
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Radiometría/estadística & datos numéricos , Fenómenos Biofísicos , Biofisica , Relación Dosis-Respuesta en la Radiación , Dosimetría por Película/estadística & datos numéricos , Humanos , Intensificación de Imagen Radiográfica , Radiología Intervencionista/estadística & datos numéricos , Piel/efectos de la radiación , Película para Rayos XRESUMEN
INTRODUCTION: The use of functional magnetic resonance imaging (fMRI) for clinical applications and basic neuroscience is constantly increasing. The discussion about minimum performance requirement for a correct implementation of fMRI is still open, and one of the critical points is the magnetic field strength. We tested the feasibility of fMRI at 1.0 T during motor and cognitive tasks. METHODS: Fourteen healthy subjects were scanned during a motor task and 12 while performing the Tower of London task. In the activated areas, the percentage signal change due to BOLD (blood oxygenation level dependent) contrast was analysed. To check basic image quality of the acquisition system we measured quality indices in a temporal series of images of a phantom. RESULTS: Motor and cognitive brain activations matched previous results obtained at higher field strengths. The mean percentage change over subjects in the motor task was in the range 1.3-2.6% for the primary motor area and 0.8-6.7% for the cerebellum. In the cognitive task, the mean percentage change over subjects was 0.7-1.2% for a frontal area and 0.6-2.8% for a parietal area. The percentage noise of the phantom temporal series was less than 0.4%. Percentage changes and signal to noise ratio, although lower than that obtained with high-field systems, allowed activation maps to be obtained in all subjects. CONCLUSION: Our results replicate previous fMRI results demonstrating reproducible motor-related brain activations and extend the field to a complex cognitive task, thus providing evidence of the safety for routine clinical use of 1-T equipment.
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Encéfalo/fisiología , Cognición/fisiología , Imagen por Resonancia Magnética , Actividad Motora/fisiología , Adulto , Estudios de Factibilidad , Femenino , Humanos , Procesamiento de Imagen Asistido por Computador , Masculino , Valores de Referencia , Análisis y Desempeño de TareasRESUMEN
There is a growing interest in Gafchromic films for patient dosimetry in radiotherapy and in radiology. A new model (XR-QA) with high sensitivity to low dose was tested in this study. The response of the film to different x-ray beam energies (range 28-145 kVp with various filtrations, dose range 0-100 mGy) and to visible light was investigated, together with the after exposure darkening properties. Exposed films were digitized with a commercially available, optical flatbed scanner. A single functional form for dose versus net pixel value variation has been determined for all the obtained calibration curves, with a unique fit parameter different for each of the used x-ray beams. The film response was dependent on beam energy, with higher colour variations for the beams in the range 80-140 kVp. Different sources of uncertainties in dose measurements, governed by the digitalization process, the film response uniformity and the calibration curve fit procedure, have been considered. The overall one-sigma dose measurement uncertainty depended on the beam energy and decreased with increasing absorbed dose. For doses above 10 mGy and beam energies in the range 80-140 kVp the total uncertainty was less than 5%, whereas for the 28 kVp beam the total uncertainty at 10 mGy was about 10%. The post-exposure colour variation was not negligible in the first 24 h after the exposure, with a consequent increase in the calculated dose of about 10%. Results of the analysis of the sensitivity to visible light indicated that a short exposure of this film to ambient and scanner light during the measurements will not have a significant impact on the radiation dosimetry.
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Dosimetría por Película/métodos , Planificación de la Radioterapia Asistida por Computador/métodos , Película para Rayos X , Calibración , Relación Dosis-Respuesta en la Radiación , Dosimetría por Película/instrumentación , Humanos , Dosis de Radiación , Dosificación Radioterapéutica , Planificación de la Radioterapia Asistida por Computador/instrumentación , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Factores de Tiempo , Rayos XRESUMEN
PURPOSE: The purpose of this study was to present our experience with percutaneous treatment of male varicocele considering technical, clinical, seminal and dosimetric aspects. MATERIALS AND METHODS: At baseline and at 6 months' follow-up, 290 male patients aged between 18 and 37 (average age 27.3 years) with left (266 cases) or bilateral (24 cases) varicocele underwent clinical assessment, Doppler ultrasonography (US), laboratory testing of free and total serum testosterone, leutenising hormone (LH) and follicle stimulating hormone (FSH) gonadotropins, inhibin B and spermiogram. In 223 cases, selective catheterisation of the spermatic vein was performed with a right transfemoral approach. Two hundred and six out of 223 underwent radiological treatment of varicocele; in 194, hydroxy-poliethoxydocanol (Aetoxysclerol) was used only whereas in 12 cases (5.8%), 5 ml of absolute alcohol and a Gianturco coil (0.038-in. Cook coil, 10 mmx50 mm) were also used. In 17/223 patients (7.6%), sclerotherapy was contraindicated or not technically feasible. Sixty-seven patients refused radiological treatment and were used as a control group. In 20 patients, the following parameters were measured: dose area product, entrance surface dose, effective dose and gonad dose. RESULTS: Technical success was achieved in 206/223 cases; two phlebographic examinations (immediately following administration of the sclerosing agent and after 15-20 min) showed prethrombotic endoluminal alterations of the internal spermatic vein. At 6 months' follow-up, 172/206 patients (83.49%) showed complete resolution of the varicocele whereas 34/206 (16.5%) had only partial disengorgement of the pampiniform plexus. In these 206 patients, the spermogram showed a significant increase in sperm concentration (52.1+/-4.1 vs. 44.2+/-3.6 million/ml, p=0.002) and motility (40.5+/-2.2 vs. 33.3+/-2.0%, p=0.0001), with negligible morphological changes. In the control group and in the other 17 untreated patients, no variations in seminal parameters were observed. The following minor procedural complications were recorded: two cases of acute abdominal pain, three of vagal crisis during administration of sclerosing agent that resolved spontaneously and two of spermatic cord inflammation that resolved within days after medical therapy. We recorded no statistically significant differences with regard to testicular volume or serum hormone levels between the treated and untreated groups. Maximum effective dose and maximum gonad dose equivalent were 6.9 mSv and 0.69 mSv, respectively. DISCUSSION AND CONCLUSIONS: Percutaneous radiological treatment of varicocele is a minimally invasive technique, which is well tolerated by patients and able to significantly improve seminal parameters. The principal technical limitation to percutaneous treatment is related to difficult selective catheterisation of the spermatic vein due to anatomic alterations, spasms and intimal dissection of the vein. Moreover, when the cremasteric vein is incontinent, inguinal surgical ligation provides better results. In the majority of cases, administration of at least 3 ml sclerosing agent at 3% ensures occlusion of the gonadic vein above the abdominal collaterals, which are responsible for long-term recurrence if not treated. In the remaining cases, absolute alcohol and metallic coils can be used to complete the treatment. The positive results in seminal parameters do not, however, allow for reliable assessment of patients' fertility. Finally, we believe that radiological procedures are not indicated or justified when prolonged catheterisation with elevated gonadic irradiation is needed.
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Varicocele/terapia , Adolescente , Adulto , Angiografía , Cateterismo Periférico , Contraindicaciones , Embolización Terapéutica/instrumentación , Etanol/uso terapéutico , Hormona Folículo Estimulante/sangre , Estudios de Seguimiento , Gonadotropinas/sangre , Humanos , Inhibinas/sangre , Hormona Luteinizante/sangre , Masculino , Polidocanol , Polietilenglicoles/uso terapéutico , Dosis de Radiación , Radiografía Intervencional , Soluciones Esclerosantes/uso terapéutico , Escleroterapia , Vesículas Seminales/irrigación sanguínea , Recuento de Espermatozoides , Testosterona/sangre , Resultado del Tratamiento , Ultrasonografía Doppler , Varicocele/diagnóstico por imagenRESUMEN
Quality controls for testing the performance of computed radiography (CR) systems have been recommended by manufacturers and medical physicists' organizations. The purpose of this work was to develop a set of image processing tools for quantitative assessment of computed radiography quality control parameters. Automatic image analysis consisted in detecting phantom details, defining regions of interest and acquiring measurements. The tested performance characteristics included dark noise, uniformity, exposure calibration, linearity, low-contrast and spatial resolution, spatial accuracy, laser beam function and erasure thoroughness. CR devices from two major manufacturers were evaluated. We investigated several approaches to quantify the detector response uniformity. We developed methods to characterize the spatial accuracy and resolution properties across the entire image area, based on the Fourier analysis of the image of a fine wire mesh. The implemented methods were sensitive to local blurring and allowed us to detect a local distortion of 4% or greater in any part of an imaging plate. The obtained results showed that the developed image processing tools allow us to implement a quality control program for CR with short processing time and with absence of subjectivity in the evaluation of the parameters.
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Intensificación de Imagen Radiográfica/métodos , Interpretación de Imagen Radiográfica Asistida por Computador/métodos , Radiografía/métodos , Tecnología Radiológica/métodos , Calibración , Análisis de Fourier , Humanos , Procesamiento de Imagen Asistido por Computador , Rayos Láser , Modelos Estadísticos , Fantasmas de Imagen , Control de Calidad , Dosis de Radiación , Reproducibilidad de los Resultados , Factores de TiempoRESUMEN
Dose estimation in interventional neuroradiology can be useful to limit skin radiation injuries. The purpose of this study was to evaluate the role of entrance skin dose (ESD) maps in planning exposure condition optimisation. Thirteen cerebral angiography and five embolisation procedures were monitored, measuring ESD, dose-area product (DAP) and other operational parameters. A transmission ionisation chamber, simultaneously measuring air kerma and DAP, measured dose-related quantities. Data acquisition software collected dosimetric and geometrical data during the interventional procedure and provided a distribution map of ESD on a standard phantom digital image, with maximum value estimation. Values of 88-1710 mGy for maximum skin dose and 16.7-343 Gy cm2 for DAP were found. These data confirm the possibility of deterministic effects during therapeutic interventional neuroradiological procedures like cerebral embolisation. ESD maps are useful to retrospectively study the exposure characteristics of a procedure and plan patient exposure optimisation.
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Angiografía Cerebral/métodos , Embolización Terapéutica/métodos , Neurorradiografía/métodos , Radiología Intervencionista/métodos , Radiometría/métodos , Piel/efectos de la radiación , Adulto , Anciano , Relación Dosis-Respuesta en la Radiación , Fluoroscopía/métodos , Humanos , Persona de Mediana Edad , Dosis de Radiación , Factores de TiempoRESUMEN
Interventional neuroradiology can involve very high entrance skin doses to patients and has the potential to induce deterministic radiation effects to the skin. A monitoring system indicating the maximum entrance skin dose during procedures could be useful to avoid skin injuries and to optimize technical parameters. Such evaluation is difficult, because exposure conditions change many times during each procedure. A data acquisition system for real time estimation of patient dose was developed, using a transmission ionization chamber connected to a personal computer, simultaneously measuring air kerma and dose area product. Input data were processed by a software that provided a map of entrance skin dose and stored all the information in a database. The method was first applied during 16 interventional procedures and was found to be suitable to this application thanks to the short time necessary for dose measurements, simplicity of use and absence of interference with the procedure execution. The uncertainty of estimation of maximum entrance skin dose was evaluated to be about 20% at the 1 sigma level.
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Algoritmos , Neurorradiografía , Piel/efectos de la radiación , Programas Informáticos , Humanos , Dosis de RadiaciónRESUMEN
PURPOSE: To verify the suitability of indicative quantities to evaluate the risk related to patient exposure, in abdominal and vascular interventional radiology, by the study of correlations between dosimetric quantities and other indicators. MATERIAL AND METHODS: We performed in vivo measurements of entrance skin dose (ESD) and dose area product (DAP) during 48 procedures to evaluate the correlation among dosimetric quantities, and an estimation of spatial distribution of exposure and effective dose (E). To measure DAP we used a transmission ionization chamber and to evaluate ESD and its spatial distribution we used radiographic film packed in a single envelope and placed near the patient's skin. E was estimated by a calculation software using data from film digitalisation. RESULTS: From the data derived for measurements in 27 interventional procedures on 48 patients we obtained a DAP to E conversion factor of 0.15 mSv / Gy cm2, with an excellent correlation (r=.99). We also found a good correlation between DAP and exposure parameters such as fluoroscopy time and number of images. The greatest effective dose was evaluated for a multiple procedure in the hepatic region, with a DAP value of 425 Gy cm2. The greatest ESD was about 550 mGy. For groups of patients undergoing similar interventional procedures the correlation between ESD and DAP had conversion factors from 6 to 12 mGy Gy-1 cm-2. CONCLUSION: The evaluation of ESD and E by slow films represents a valid method for patient dosimetry in interventional radiology. The good correlation between DAP and fluoroscopy time and number of images confirm the suitability of these indicators as basic dosimetric information. All the ESD values found are lower than threshold doses for deterministic effects.