The role of high-energy computed radiography(CR)in radiotherapy

Computed radiography(CR)imaging has high irradiation tolerance and it is easy to archive CR images along with other image information by Digital Imaging and Communications in Medicine(DICOM)format,and to process them.CR can be used in radiation Quality Control(QC)task and verification of treatment setting-up.In this paper,the role of high-energy CR in radiation oncology is studied.The patients were imaged by CR system and EPID before radiotherapy.All verification images were acquired with 1–2 MU(Monitor Unit)using 6 MV X-rays.QC for a linac was done with film and high-energy CR to collect the data on daily,weekly and monthly basis.The QC included Multileaf Collimators(MLC)calibration and mechanical iso-centre check.CR was also adapted to verify patient position,the film was used to compare with digitally reconstructed radiographs(DRR)and portal image from EPID. Treatment setting-up was verified based on the result of comparison.High quality verification images could be acquired by the CR system.Comparing to EPID,the results showed that the system was suitable for practical use to acquire daily verification images,and it was useful to fulfill part of quality assurance(QA)in radiation oncology.The quality of image acquired by the high-energy CR system is comparable or even better than DRRs and portal images. The final treatment set-up for the patients could be verified more accurately with the CR system.

图像融合技术在Computed Radiography影像中的应用研究

将图像融合技术应用于CR(ComputedRadiography)技术中 ,有效改善影像的信噪比 (signal-to -noiseratio)。运用双IP(ImagePlate)技术采集人体体模影像后 ,在变换域进行图像配准。建立融合图像的数学模型 ,基于此模型对配准完成的源图像实施不同权重的加权计算得到融合图像。结果 融合图像信噪比源图像可提高 30 %左右。结论 将图像融合技术应用于CR技术可有效改善影像质量 ,有助于提高诊断的准确性。

Does the use of computed tomography scenogram alone enable diagnosis in cases of bowel obstruction?

BACKGROUND Ileus is a pathological condition of the abdomen that presents as a medical emergency.It is characterized by potential complications such as perforation and ischemia,which can lead to significant morbidity and mortality if not promptly addressed.The successful management of ileus relies heavily on the timely and precise identification of the condition.While conventional radiography(CR)is commonly used as the primary diagnostic tool,its accuracy in identifying obstructions ranges from 46%to 80%.Furthermore,the diagnostic accuracy of identifying the location and etiology of intestinal obstruction by CR is limited,therefore making computed tomography(CT)the ideal imaging modality in this regard.AIM To determine the presence of acute bowel obstruction(BO)on abdominal CT scenogram images and the accuracy of determining its possible location,taking into account the experience of the observers.METHODS A retrospective screening was conducted on an ensemble of 46 individuals who presented to the emergency department between January 2021 and January 2022 with severe abdominal pain and were subsequently monitored for suspected ileus.The abdominal CT scans of these patients were assessed by three radiologists with varying levels of experience(1,3,and 10 years)at different intervals(1 mo apart).The evaluation focused on determining the presence or absence of BO,as well as identifying the potential location of the obstruction(small bowel or large bowel).The study employed Kappa statistics to assess inter observer variances,while the McNamer test was used to evaluate obstruction and segmentation discrepancies between observations.A significance level of P<0.05 was determined to indicate statistical significance.RESULTS Out of the total sample size of 46 patients,15 individuals(32.6%)were identified as female,while the remaining 31 individuals(67.4%)were identified as male.The ultimate diagnosis of 42 instances(91.3%)indicated ileus resulting from mechanical obstruction(MO).Among these patients,14(33%)experienced obstruction in the large bowel(LB),while 28(66%)experienced obstruction in the small bowel(SB).The initial evaluation yielded sensitivity rates of 76.19%,83.31%,and 83.33%,and diagnostic accuracy rates of 69.56%,76.08%,and 80.43%for the detection of BO among the three observers.The initial study revealed that the average sensitivity of three observers in detecting the presence of ileus caused by MO was 80.94%,while the diagnostic accuracy was 75.35%.Based on the first evaluation,the senior observer demonstrated the highest sensitivity(85.71%),negative predictive value(92.60%),and diagnostic accuracy(80.43%)when accurately estimating the thick and thin segmentation,as per the final diagnosis.There was no statistically significant disparity observed in the sensitivities pertaining to the identification of ileus during the second assessment,as well as the precise determination of the segment level inside the LB or SB,when comparing the second and third observers.Nevertheless,although there was no statistically significant alteration in the detection rate of ileus by the first observer,there was a notable rise in the accuracy rate of segment estimating(73.91%).The senior assessor had a higher level of accuracy in assessing the existence of ileus and segmentation compared to the other evaluators in both evaluations.CONCLUSION The findings of our study indicate that the sensitivity and accuracy rates of abdominal CT scenogram scans in diagnosing acute MOs are similar to or greater than those of CR.Additionally,the study revealed that radiologists with more experience demonstrated a higher likelihood of accurately predicting the existence and potential localization of MO compared to their less experienced counterparts.

A Derived Exposure Chart for Computed Radiography in a Negroid Population

Background: Computed radiography has a wider exposure latitude when compared with film-screen imaging system. Consequently, the risk of dose creep is high. A conscientious effort is there-fore, needed by the radiographer to keep exposure as low as reasonably achievable. Objective: To derive a computed radiography exposure chart for a negroid population using AGFA photostimulable phosphor plates and a GE static X-ray machine. Materials and Method: A static X-ray machine, a digitizer, and photostimulable phosphor plates were used for the X-ray examination. Chest examinations were done at a Focus-Film-Distance (FFD) of 150 - 180 cm while all other examinations were conducted at 90 - 100 cm FFD. The range of exposure factors (kVp, mA and mAs) used by radiog-raphers in the centre was noted and the 90th percentile calculated. Over a three-month period, the patients were examined with the 90th percentile of tube potential (kVp) while keeping other factors constant. The kVp was gradually decreased and halted if radiologists and radiographers uncon-nected with the work expressed misgivings about the quality of the image. A similar procedure was adopted for the tube current (mA). The threshold adopted as low as reasonably achievable was the factor preceding the point of observation by other personnel. Metrics for central tendency from the statistical packages for social sciences, version 17.0 was used to analyze the data. Results: 335 subjects of both gender aged 0 - 92 years were examined by the researchers. Adult exposure factors used by the radiographers (and those derived by the researchers) had a range of 45 - 130 kVp (62 - 94 kVp), 63 - 320 mA (100 - 250 mA) and 4.0 - 25.0 mAs (5.0 - 20.0 mAs) respectively. Pediatric chest (and researchers-derived) factors were 50 - 75 kVp (52 - 65 kVp), 50 - 250 mA (100 - 220 mA) and 3.20 - 10.0 mAs (3.2 - 6.5 mAs) respectively. Conclusion: Upper threshold of adult (and paediatric) exposure factors in computed radiography with comparable equipment and accessories should not exceed 94 kVp (65 kVp), 250 mA (220 mA) and 20.0 mAs (6.5 mAs) respectively. The derived exposure chart is also adequate to address motion unsharpness in chest examinations.

增材制造材料中的CR检测应用

作为近净成形的新兴制造工艺,增材制造应用广泛,其逐点融合的工艺特点,容易产生气孔、结合不良等缺陷。针对该问题,通过分析增材制造材料CR检测过程中成像板、金属屏、透照电压及曝光量等参数,并将增材制造材料CR与RT的成像结果等进行对比,得出CR的优势及适用范围,以便更好指导检测业务的开展。

Economic Evaluation of Conventional Radiography with Film and Computed Radiography: Applied at BMC

Conventional radiography with film (CRF) has been in use for diagnostic purposes for a long time now. It has proved to be a great assert for the radiographers in assessing various abnormalities. With recent advances in technology it is now possible to have digital solutions for radiography problems at a very cost effective, environment friendly and also with better image quality in certain applications when compared to CRF. Rather than using a CRF a computed radiography (CR) uses imaging plates to capture the image. The imaging plate contains photosensitive phosphors which contain the latent image. Later this plate is introduced into a reader which is then converted into a digital image. The major advantage and the cost effective element of this system is the ability to reuse the imaging plates unlike the photographic film where in only a single image can be captured and cannot be reused. The computed radiography drastically reduces the cost by eliminating the use of chemicals like film developers and fixers and also the need for a storage room. It also helps to reduce the costs that are involved in the disposal of wastes due to conventional radiography. This paper investigates whether it is cost effective to use computed radiography over film based system at Al-Batnan Medical Center (BMC), Tobruk, Libya by using Cost Benefit Analysis (CBA). Apart from the initial cost of the CR System, based on the data collected from the center, from the year 2008 to 2012 (until June 2012) a total of 581,566 images were produced with the total cost incurred using film based system being USD 4,652,528. If the same number of images were produced using a CR system the total cost incurred would have been USD 82,600. Taking into consideration the cost of a new CR system to be USD 120,000 the overall cost of producing these images is USD 202,600. It is observed that an amount of USD 4,449,928 could have been saved over the period of 5 years starting from 2008 to 2012 by using the CR system at BMC. Using Cost Benefit Analysis, the average value of the net difference between the costs and benefits for the conventional film based system is ?83.38 where as for the Computed System it is 22.06. Based on the principles of Cost Benefit Analysis it can be concluded that the system with a net positive difference is more cost beneficial than the other. With the help of the above two analysis it can be concluded that the use of computed radiography is definitely more cost effective for use at BMC, when compared to the conventional x-ray radiography.

Comparative Study of Clinical Manifestation, Plain Film Radiography and Computed Tomography for Diagnosis of Maxillofacial Trauma

Objective: Maxillofacial injuries are one of the commonest injuries encountered. Roentgenographic evaluation of maxillofacial trauma is of prime importance for diagnosis and treatment of these injuries. Study Design: Forty patients were evaluated in the prospective four-year study. We studied and evaluated the demography and diagnostic efficacy of clinical, plain radiography, and computed scan in maxillofacial trauma. Result: Road traffic accidents were the commonest cause of maxillofacial injuries. Patients having multiple fractures, mandibular fractures were the commonest. Conclusion: Computed tomography proved a useful adjunct in midfacial trauma.

海洋工程领域数字射线CR与射线胶片检测技术的对比分析

随着射线检测技术的不断发展以及对环保要求的不断提高,CR计算机射线照相检测技术在各领域得到了广泛应用。为了解CR技术和射线胶片检测技术的异同,在理论和试验的基础上,针对海洋工程领域的射线检测工作(主要为管线焊缝),在原理、环保、工效、再射率和缺陷检测等方面,展开了CR技术与射线胶片检测技术的对比分析。结果表明,相比射线胶片检测技术,CR技术在环保、工效和再射率方面均有一定的优势。

Clinical Endodontic Applications of Cone Beam-Computed Tomography in Modern Dental Practice

Nearly two decades since Cone Beam-Computed Tomography (CBCT) was introduced in dentistry, this technology has been proven to be a useful asset in modern dental practice. The information gleaned from a CBCT scan influences treatment decisions and prognostication of challenging endodontic cases. The authors present six cases that utilized CBCT to diagnose vertical root fracture, to assess resorption, to guide the clinician in overcoming anatomical complexities, to hurdle diagnostic dilemmas and to perform pre-surgical evaluation. Initially, a thorough clinical assessment was performed;however, conventional periapical radiographs were not able to provide sufficient information to arrive at a definite diagnosis or a thorough treatment plan. CBCT was therefore deemed helpful for these cases. Clearly, there are advantages to using CBCT. With a better understanding of each case, the clinician can plan a definitive treatment plan and offer a clearer case prognosis to their patient.

Parallel computing approach for efficient 3-D X-ray-simulated image reconstruction

Accurate 3-dimensional(3-D)reconstruction technology for nondestructive testing based on digital radiography(DR)is of great importance for alleviating the drawbacks of the existing computed tomography(CT)-based method.The commonly used Monte Carlo simulation method ensures well-performing imaging results for DR.However,for 3-D reconstruction,it is limited by its high time consumption.To solve this problem,this study proposes a parallel computing method to accelerate Monte Carlo simulation for projection images with a parallel interface and a specific DR application.The images are utilized for 3-D reconstruction of the test model.We verify the accuracy of parallel computing for DR and evaluate the performance of two parallel computing modes-multithreaded applications(G4-MT)and message-passing interfaces(G4-MPI)-by assessing parallel speedup and efficiency.This study explores the scalability of the hybrid G4-MPI and G4-MT modes.The results show that the two parallel computing modes can significantly reduce the Monte Carlo simulation time because the parallel speedup increment of Monte Carlo simulations can be considered linear growth,and the parallel efficiency is maintained at a high level.The hybrid mode has strong scalability,as the overall run time of the 180 simulations using 320 threads is 15.35 h with 10 billion particles emitted,and the parallel speedup can be up to 151.36.The 3-D reconstruction of the model is achieved based on the filtered back projection(FBP)algorithm using 180 projection images obtained with the hybrid G4-MPI and G4-MT.The quality of the reconstructed sliced images is satisfactory because the images can reflect the internal structure of the test model.This method is applied to a complex model,and the quality of the reconstructed images is evaluated.

Optimization of Exposure Conditions for Computed Radiology Exams in Neonatal Intensive Care

This paper performs a review of existing literature about neonatal imaging in intensive care;we notice that the multiplicity of approaches results in different and sometimes conflicting solutions to optimize acquisition technique of X-ray images. European Guidelines still refer to screen-film combinations used in past decades, current usage of digital technology requires an additional effort to reduce dose to infants and to optimize the sensor’s response exploiting their properties. In this work we investigate response changes of digital medium (computed radiography plates), due to alterations of the beam through incubators components. All combinations in use in our Hospital were tested for evaluating dosimetry and image quality and new exposure solutions were devised to optimize radiology exams, taking into account solutions suggested by the equipments makers. Dose measured was compared with dose levels suggested by European Guidelines, evaluating radiation-induced risk too. Image quality was evaluated in a double-blind comparison by radiologists. An easily repeatable optimization procedure is proposed intended to reduce delivered dose well below European guidelines. The proposed study allowed us to instruct the technologists on the most appropriate methodology for performing the radiology exam, by standardizing the approach to Neonatal Intensive Care Units. We have demonstrated also to radiologic technologists reluctant to use the X-ray tray, as it may optimize imaging in the incubator. We were also able to reduce dose—and radiation-induced risk too—of 37% - 67% depending on the previously used operating mode.

Use of dentomaxillofacial cone beam computed tomography in dentistry

Cone-beam computed tomography(CBCT) was developed and introduced specifically for dento-maxillofacial imaging. CBCT possesses a number of advantages over medical CT in clinical practice, such as lower effective radiation doses, lower costs, fewer space requirements,easier image acquisition, and interactive display modes such as mutiplanar reconstruction that are applicable to maxillofacial imaging. However, the disadvantages of CBCT include higher doses than two-dimensional imaging; the inability to accurately represent the internal structure of soft tissues and soft-tissue lesions; a limited correlation with Hounsfield Units for standardized quantification of bone density; and the presence of various types of image artifacts, mainly those produced by metal restorations. CBCT is now commonly used for a variety of purposes in oral implantology, dentomaxillofacial surgery, image-guided surgical procedures, endodontics, periodontics and orthodontics. CBCT applications provide obvious benefits in the assessment of dentomaxillofacial region, however; it should be used only in correct indications considering the necessity and the potential hazards of the examination.

胸部CT图像质量评价与辐射剂量的临床应用研究

目的:归纳和分析影响胸部CT图像质量的因素,进一步对照分析常规剂量组和低剂量组两组图像质量有无差异,以论证胸部CT低剂量检查的可行性。方法:选取150例胸部CT查体的患者,A组为常规剂量组,管电压120kV,管电流自动调节;B组为低剂量组,管电压100kV,管电流自动调节。参照胸部CT的图像质量评价标准对常规剂量组和低剂量组图像质量进一步作出主观评价。对辐射剂量、信噪比等客观数据进行统计学处理,以P<0.05为差异有统计学意义。并与主观评价相比较。结果:主、客观评价两组图像质量均无统计学意义,A组辐射剂量与B组辐射剂量有统计学意义。结论:影响图像质量的因素包括患者的因素、设备的因素以及操作者的因素,胸部CT采用100kV低剂量检查可以作为常规扫描方案,获得的图像可以满足影像诊断的要求,具有可行性。

基于下肢全长X线片及CT平扫探讨鹅足肌腱对胫骨高位截骨术后胫骨远端轴位旋转的影响

目的:基于下肢全长X线片及CT平扫探讨内侧开放楔形胫骨高位截骨术(MOWHTO)后鹅足肌腱的有无对胫骨远端相对于胫骨近端轴位旋转的影响。方法:回顾性收集行MOWHTO的患者63例,根据术中对鹅足肌腱的处理情况,分为未松解组(对照组)、部分松解组(观察组1)和完全松解组(观察组2)各21例(21膝);同时收集自体腘绳肌腱行前交叉韧带重建的患者(观察组3)21例(21膝)。患者术前及术后1周内均行下肢全长正侧位X线检查及髋膝踝CT平扫,测量解剖股骨胫骨角(aFTA)、胫骨近端内侧角(MPTA)和胫骨扭转角(TTA),并进行比较。结果:观察组1、观察组2、观察组3及对照组aFTA分别由术前(180.85±2.51)°、(180.30±2.18)°、(181.01±2.06)°和(181.34±1.98)°,矫正为术后(173.85±1.83)°、(174.11±1.34)°、(173.33±1.56)°和(174.26±1.77)°;MPTA由术前(80.23±1.83)°、(79.37±1.62)°、(81.01±1.52)°和(80.90±1.37)°,矫正为术后(89.54±2.33)°、(88.26±1.89)°、(87.58±1.01)°和(88.42±1.25)°。4组间术前aFTA、术后aFTA、术前MPTA、术后MPTA的差异均无统计学意义(均P>0.05);4组术后与术前TTA差值分别为(-0.52±0.99)°、(-0.07±2.06)°、(-0.13±1.37)°和(-0.89±1.21)°,观察组2、观察组3与对照组相比,差异均有统计学意义(均P<0.05)。结论:完整的鹅足肌腱可导致MOWHTO后胫骨远端相对于胫骨近端内旋,对其进行松解会削弱此作用,在MOWHTO中需合理处理鹅足肌腱,以尽量避免非计划的胫骨扭转。

子宫肉瘤的CT及MRI影像学表现

目的 分析并总结子宫肉瘤的CT及MRI影像表现。方法 回顾性分析15例经病理及手术证实为子宫肉瘤患者的临床特征、CT及MRI表现,总结并探讨其特征性影像学表现。结果 15例子宫肉瘤患者中包括子宫平滑肌肉瘤患者8例,其中4例病灶局限于宫腔内,4例表现为盆腔巨大包块,8例病灶均呈囊实性包块;未分化子宫肉瘤1例,呈类圆形短T_(1)、长T_(2)信号,边界清,DWI呈边缘环形高信号;子宫腺肉瘤2例,表现结节状、团块状混杂密度病灶,增强扫描呈明显不均匀强化;低级别子宫内膜间质肉瘤3例,均呈T_(1)WI等或低信号、T_(2)WI高或稍高信号且DWI呈明显高信号;高级别子宫内膜间质肉瘤1例,表现为盆腔内巨大囊实性占位,病理证实病灶侵穿浆膜累及局部肠壁浆膜下组织。结论 子宫肉瘤常表现为盆腔内囊实性包块,体积较大,形态不规则,可侵犯邻近结构或发生远处转移。MRI表现较具有特征性,常表现为等或稍长T_(1)WI、混杂长T_(2)WI信号,DWI呈高或略高信号,增强扫描肿块呈明显不均匀强化。

CR在鼻骨骨折检查中的作用

目的 :为探讨CR在鼻骨骨折检查中的作用 ,回顾性分析了 4 0例鼻骨骨折患者的鼻骨侧位CR片及普通X线平片。结果 :4 0例鼻骨骨折在CR片上均有不同程度X线表现 ,而普通X线平片仅发现鼻骨骨折 19例。结论 :鼻骨侧位CR片对鼻骨骨折及其它面骨复合骨折的诊断敏感性高于普通X线平片 ,CR片骨折线显示清晰 ,综合信息量高 。

CR影像处理参数调节原理及优化方法

目的:研究CR影像密度、对比度、组织均衡、空间频率、LUT曲线等计算机X线摄影影像处理参数的调节原理及优化方法。方法:应用Konica REGIUS MODEL170 CR,在其控制台CS-1上调节各种影像参数。结果:可以优化人体各部位影像,提高影像质量。结论:全面掌握了计算机X线摄影处理参数的调节方法,并合理有效地组合运用,就能够获得优质医学影像。

CR、CT、MRI在脊柱结核诊断中的临床价值

[目的]评价计算机X线摄影(CR)、计算机断层成像(CT)、磁共振成像(MRI)在脊柱结核诊断中的临床价值。[方法]回顾分析经病理证实的41例脊柱结核的影像学资料。41例做了CR,22例做了CT,31例均做了MRI。[结果]41例中38例CR片清晰显示骨质改变及椎间隙狭窄或消失,30例CR片可看到软组织阴影。22例CT均清晰显示了钙化,22例CT检查附件均未见明显异常,21例CT清晰显示椎体骨质改变,20例CT显示了软组织阴影。31例MRI均显示软组织均受累,附件均未见受累,其中29例椎间隙狭窄或消失。病变T1WI均以低信号为主,T2WI均以高信号为主。[结论]CR片仍为脊柱结核的基本检查方法,CT较好显示了结核的破坏范围及细微钙化,MRI对显示结核的侵犯范围、软组织异常及椎间盘异常有明显优势。三者相结合有助于脊柱结核的诊断。

CR、CT、MRI在骨肿瘤诊断中的临床价值

[目的]评价计算机X线摄影(CR)、CT、磁共振成像(MR l)在骨肿瘤诊断中的临床价值。[方法]回顾分析55例经病理证实的影像学资料,其中55例均有CR平片,21例CT扫描,20例做了MR I检查。[结果]55例中51例CR片清晰显示骨质改变,40例CR片清晰显示病灶边界,20例CR片清晰显示骨膜反应,19例CR片清晰显示病灶内有大小不一钙化。21例行CT扫描病例均清晰显示骨质改变、病灶边界、病灶内有大小不一钙化,8例清晰显示骨膜反应。20例做了MR I检查病例均清晰显示病灶边界及软组织肿块,8例显示相应骨髓水肿。[结论]CR片仍为骨肿瘤的首选检查方法,CT较好显示了肿瘤的范围及细微结构,MR I对显示肿瘤的范围、软组织肿块及相应骨髓水肿有明显优势。三者相结合有助于骨肿瘤的诊断。