Dose estimation of X-ray radiography based on Chinese pediatric reference phantoms / 中华放射医学与防护杂志

Objective:The Chinese pediatric mesh-type reference phantoms were developed and applied in the dose assessment of X-ray radiography.Methods:The 5- and 10-year-old Chinese pediatric mesh-type reference phantoms were developed based on the CT data. Based on the phantoms, the Monte Carlo method was applied to simulate the X-ray radiography to calculate the organ dose conversion coefficient and the effective dose conversion coefficient in different radiography conditions.Results:The 5- and 10-year-old Chinese pediatric mesh-type reference phantoms were developed, and the physical parameters were consistent with the national standard. The differences of the organ mass between the established phantoms and reference data were within 2%. The database of the pediatric chest posteroanterior projection and abdominal anteroposterior projection, tube voltage 60-90 kVp, total filtration 2.5~4 mmAl were simulated, and the difference between the effective dose conversion factor and the literature result was within 3%.Conclusions:The established Chinese pediatric mesh-type reference phantoms can be applied in the studies of radiation protection and clinical medicine and their result can provide an important reference for the dose assessment of the pediatric X-ray radiography.

Anatomical changes and imaging manifestations of childhood developmental dysplasia of the hip / 中国组织工程研究

BACKGROUND: Developmental dysplasia of the hip is a common hip developmental deformity in children. Clinical treatment of developmental dysplasia of the hip differs in different periods. Early treatment has better efficacy, fewer complications, and better long-term prognosis. It can reduce the recurrence rate, reduce economic pressure, and improve the quality of life. Therefore, early diagnosis of developmental dysplasia of the hip is becoming more and more important clinically. OBJECTIVE: To review the research progress of anatomical changes and imaging manifestations of developmental dysplasia of the hip. METHODS: “DDH, Anatomy, X-ray Radiography, CT, MRI, Ultrasound” were used as English search terms. “Developmental hip dysplasia; anatomy; X-ray photography; CT; MRI, ultrasound” were used as Chinese search terms. The authors searched English databases such as PubMed and Springerlink, and Chinese databases such as Wanfang and CNKI from January 1990 to December 2019. Irrelevant and repetitive articles were excluded, and finally 55 articles were included for review. RESULTS AND CONCLUSION: Imaging diagnosis as a non-invasive examination method has become the preferred examination method for the diagnosis of developmental dysplasia of the hip, and its anatomical changes are more conducive to clinical imaging diagnosis. Routine X-ray examination can be used for rapid screening of developmental dysplasia of the hip. MRI helps to distinguish the early signal changes of soft tissue structure and bony structure. Three-dimensional CT can evaluate the acetabular bone structure changes from multiple angles, excluding the obstruction caused by posture factors. Ultrasonography is more sensitive to fluid and can also perform early screening of developmental dysplasia of the hip. Thus, different imaging examinations have their advantages and complement each other to improve the early diagnosis rate of developmental dysplasia of the hip.

Exploring the possibility of radiography in emission mode at higher energies: Improving the visualization of the internal structure of paintings / Explorando las posibilidades de la radiografía en modo de emisión a altas energías: Cómo optimizar la visualización de la estructura interna en pinturas

Summary We demonstrated in previous investigations that the internal structure of paintings can be visualized with conventional radiography in transmission mode when paintings have the proper stratigraphy. Unfortunately, there are many paintings that do not result in useful images. This problem can be solved by using radiography in emission mode. With this technique, the painting is irradiated with high energetic X-rays originating from an X-ray tube operating at 100 keV - 320 keV while inside the painting low energetic signals such as photoelectrons or characteristic photons are being generated. These signals escape from the top 10 µm of the painting and are able to illuminate the imaging plate. However, this technique has also some disadvantages. One of them is that it is not able to visualize underlying paintings. In this study, we explored the possibility to enhance the information depth by increasing the energy of the photon source from 100 keV up to 1.3325 MeV (i.e., 60Co source). At the same time, we also studied how the contrast between pigments is generated in emission mode. For this, we used mathematical simulation of particle transport in matter to understand the relation between input particle (particle type such as photon, electron or positron and the energy of the particle), the material being irradiated (element from which it is composed, thickness and density) and the output signal (generated particle types and energy). Finally, we will show that it is possible to image paintings using a 192Ir and even a 60Co source.

Resumen En investigaciones previas se ha demostrado que la estructura interna de las pinturas se puede visualizar satisfactoriamente con la radiografía convencional en modo de transmisión, siempre y cuando dichas pinturas tengan la estratigrafía adecuada. Desafortunadamente, hay muchos casos en los que la aplicación de este método no resultan en imágenes útiles. Este problema puede ser resuelto usando la radiografía en modo de emisión. Con esta técnica, la pintura se irradia con rayos X de alta energía originados en un tubo de rayos X trabajando entre 100 keV y 320 keV. Esto genera señales de baja energía (fotoelectrones o fotones característicos) en el interior de la pintura que, al escapar de las 10 μm superiores, pueden iluminar una placa de imágenes. No obstante, su aplicación también implica ciertas desventajas. Una de ellas es la incapacidad de visualizar las pinturas subyacentes. En este estudio, exploramos la posibilidad de incrementar la información obtenida a mayores profundidades aumentando la energía de la fuente de fotones desde 100 keV hasta 1.3325 MeV (fuente de 60Co). También estudiamos el impacto de esta energía en el contraste obtenido entre los pigmentos. Para esto, utilizamos la simulación matemática del transporte de partículas en la materia para comprender la relación entre partículas de entrada (fotones, electrones o positrones y la energía de las partículas), el material que se irradia (elemento del que está compuesto, espesor) y la señal de salida (tipos de partículas generados y energía). Finalmente, mostraremos que es posible crear imágenes de pinturas usando una fuente 60Co.

Estimation of patient radiation doses form conventional X-ray radiography / 中华放射医学与防护杂志

Objective To compare patient organ doses and entrance surface dose conversion coefficients in conventional radiography using medical internal radiation dose (MIRD) phantom and voxel human phantom.Methods The voxel phantom was adapted to the Monte Carlo transport code to simulate the organ doses and entrance surface dose in five common projections, and thus the dose conversion coefficients between the entrance skin dose and organ dose were calculated.The results were compared with the reported mean values which were simulated using MIRD phantom.Results The dose conversion coefficients values of organs covered or partially covered by the X-ray field ranged from 0.149-0.650 in chest postero-anterior projection, 0.067-0.382 in chest left lateral projection, 0.023-0.374 in chest right lateral projection, 0.035-0.431 in abdominal antero-posterior projection, 0.083-0.432 in lumbar spine antero-posterior projection.In chest postero-anterior projection, significant differences were most obviously observed in lung, the dose conversion coefficients difference was 54.3％.In chest left lateral projection, the dose conversion coefficients difference of liver was greatest, which was 54.5％.In chest right lateral projection, the dose conversion coefficients differences of stomach wall was most obviously 63.8％.In abdominal antero-posterior projection, dose conversion coefficients discrepancy was most obviously observed in spleen, with the value of 65.0％;while in lumbar spine antero-posterior projection, the dose conversion coefficients differences of stomach wall was most obviously 43.7％.Conclusions Compared with the stylized MIRD phantoms, the anatomical realism in voxel phantom is evident.Therefore, the dose conversion coefficients calculated by voxel phantoms are more accurate and scientific in conventional radiology.

Patient radiation dose of spine X-ray panoramic imaging: Comparison of two techniques based on Monte Carlo mathematical model / 中华放射医学与防护杂志

Objective To compare patient radiation dose of two techniques of spine X-ray panoramic imaging under the same image quality.Methods An anthropomorphic phantom was used.The reasonable imaging parameters were found for spine panoramic radiography using Sonialvision safire17 Slot scan with HQ mode.And the panoramic films were obtained with different parameters using GE XR650 DR system.The panoramic images were scored by three experienced radiologists.The imaging parameters with the same score in groups were input into PCXMC 2.0 software to get effective dose(E) and organ dose.Results The reasonable imaging parameters of Slot scan were high quality(HQ) mode, SID 150 cm, 100 kVp, and 2 mAs;and the corresponding parameters of XR650 were SID 200 cm, 100 kVp, and 3.2 mAs.The E of the Slot scan with HQ mode, XR650 with manual mode and XR650 with AEC mode was(0.118 7±0.001 4),(0.0847±0.0008), and (0.1580±0.001 5) mSvrespectively, while the E of XR650 with manual mode was lower than the others(F =3 007.293, P ＜0.05).The organ dose using XR650 DR with manual mode were lower than that using Slot scan with HQ mode in all samples except breasts(P ＜0.05);the organ dose using XR650 DR with AEC mode were higher than that using XR650 DR with manual mode and Slot scan with HQ mode for all samples except for thyroid, oesophagus and lungs (P ＜0.05).Conclusions The radiation doses of both spine X-ray panoramic imaging with manual mode are low, and low dose spine X-ray panoramic imaging can be achieved if reasonable parameters are used.

Imágenes radiográficas de bienes culturales obtenidas con un sistema portátil de fluorescencia de rayos X modificado / Radiography imaging of cultural heritage obtained with a midified portable x-ray fluorescence system

RESUMEN Se evalúa la suficiencia de la calidad de las imágenes radiográficas obtenidas con un espectrómetro portátil de Fluorescencia de rayos X modificado para este propósito, en el estudio de bienes culturales. El instrumento propuesto utiliza un tubo de rayos X con ánodo de Pd (2 mm) que alcanza un voltaje y corriente máximos de 50 kV y 1 mA respectivamente y un sistema de colimación que permite irradiar una región de forma cuadrada en el objeto analizado a través de la proyección de un haz de luz con igual forma sobre su superficie. La resolución espacial de las imágenes radiográficas obtenidas permitieron: localizar y defnir bien figuras subyacentes en pinturas, identificar materiales de relleno en una pintura en proceso de restauración, la radiogrametría de huesos arqueológicos y la identificación de una esfera petrificada proveniente de un hallazgo arqueológico. Se propone el análisis radiográfico para estudios cubanos de antropología física.

ABSTRACT The imaging quality of radiographies obtained with a modifi ed portable X-ray fluorescence spectrometer was evaluated for the study of cultural heritage. The proposed instrument uses an X-ray tube with (2 mm) Pd anode allowing a 50 kV maximum voltage and 1 mA current. The instrument also equipped with a collimation system, allows to irradiate a square-shaped region in the analyzed object by projecting asquare light beam on its surface. The spatial resolution of the obtained radiographic image makes possible to locate and define perfectly well underlying paintings(pentimenti), to identify filling materials in a painting undergoing a restoration process, as well as radiogrametry of archaeological bone and the identification of a petrified sphere from an archaeological discovery. The radiographic analysis is proposed for the study of physical anthropology in Cuba.

Simulation and evaluation of the absorption edge subtraction technique in energy-resolved X-ray radiography applied to the cultural heritage studies / Simulación y evaluación de la técnica de sustracción del borde de absorción en un sistema radiográfico espectrométrico destinado al estudio del patrimonio cultural

ABSTRACT In this work the mathematical simulation of photon transport in the matter was used to evaluate the potentials of a new energy-resolved X-ray radiography system. The system is intended for investigations of cultural heritage object, mainly painting. The radiographic system uses polychromatic radiation from an X-ray tube and measures the spectrum transmitted through the object with an energy-dispersive X-ray detector on a pixel-by-pixel basis. Manipulation of the data-set obtained allows constructing images with enhanced contrast for certain elements. Here the use of the absorption edge subtraction technique was emphasized. The simulated results were in good agreement with the experimental data.

RESUMEN En este trabajo se utilizó la simulación matemática del transporte de los fotones en la materia para evaluar las potencialidades de un nuevo sistema radiográfico destinado al estudio de obras del patrimonio cultural. Este sistema emplea una fuente de rayos X no monocromática y mide a nivel de píxel el espectro transmitido a través del objeto en estudio con un detector espectrométrico. El procesamiento del conjunto de datos obtenidos permite la construcción de imágenes con contraste realzado para ciertos elementos. En el presente trabajo se enfatizó en el uso de la técnica de sustracción del borde de absorción para el procesamiento de las imágenes. Los resultados de las simulaciones resultaron consistentes con las mediciones experimentales.

Pruebas automatizadas a la electrónica en un sistema de detectores de microbandas para rayos x de energía dual / Automated testing of microstripdetectors readout system for x-ray dual energy

Para la radiografía digital se requieren circuitos que realicen la recepción y procesamiento de señales nucleares de múltiples canales simultáneamente. Estos circuitos se deben someter a pruebas para caracterizar su funcionamiento. En este trabajo se describen pruebas automatizadas para controlar por software desde una computadora personal la caracterización de un sistema basado en circuitos integrados específicos del tipo RX64DTH con detectores de microbandas y se muestran los resultados.

Circuits that carry out the signal acquisition and processing by multiple channels are required in digital radiography. These circuits should be tested in order to characterize their performance. This paper describes an automated system to control (by a software, from a personal computer) the characterization of a system based on RX64DTH specific integrated circuits with microstrip detectors. The results are shown.

Analysis of image artifacts in computed radiographic system / 医疗卫生装备

Objective To investigate the appearance,causes and countermeasures of the image artifacts in a computed radiographic system.Methods Random 1968 CR images were analyzed by GE Radworks.Results Among the 1,968 images which were choosed at random,66 images with artifacts were found and processed.The artifacts in computed radiographic system are relevant to system software and hardware,dust as well as operators.Conclusion Familiarization with the appearance and causes of CR image artifacts helps to prevent or reduce artifacts.