The way we were (and how we got here): fifty years of technology changes in dental and maxillofacial radiology

The history of the last 50 years (1970–2020) of technological changes and progresses for equipment and procedures in dental and maxillofacial radiology is related from the insider perspective of an industrial physicist and technologist who has been instrumental at innovating and developing medical equipment in different parts of the world. The onset and improvement of all major categories of dental and maxillofacial radiographic equipment is presented, from the standpoint of their practical acceptance and impact among common dentists and maxillofacial radiologists: X-ray sources and detectors for intraoral radiography, and panoramic systems, both film-based and digital (including photo-stimulated phosphor plates); and cone beam CT.     

A unified computer program for assessment of attenuation correction and data acquisition methods in single photon emission computed tomography (SPECT)

A computer based simulation program was developed to assess the usefulness of various attenuation correction algorithms and data acquisition methods in single photon emission computed tomography (SPECT) in a unified approach. The program analytically calculated projection ray sums from a mathematical model with various distributions of activities and either uniform or non uniform attenuation coefficients by using the line integrals including the effect of attenuation. Data acquisition starting at arbitrary angles, various acquisition angles, including a 180° scan and a non circular orbit of a gamma camera, including an elliptical orbit can readily be taken into consideration in our simulation program. To simulate non circular orbit data acquisition, the resolution dependence on the object distance from the collimator surface was incorporated into the simulation. This computer based simulation program allows various combinations of attenuation correction algorithms such as hybrid methods, and data acquisition methods can be evaluated under a large number of study conditions. The usefulness of this computer based simulation program is shown with several representative examples.     

Health technology assessment on the use of magnetic resonance imaging (MRI) and computed tomography (CT) in the diagnosis of multiple sclerosis (MS) and clinically isolated syndromes (CIS)

This work is the result of a health technology assessment for the Flemish regional government, Belgium, performed in 2006. A search of the available literature in the databases Medline and EMBASE was performed to find evidence for a rational choice between CT and MRI techniques in the work-up of patients with clinically isolated syndrome (CIS) with a suspicion for multiple sclerosis (MS), and in follow-up exams performed in such patients. From the presented evidence, in patients referred for CIS or MS, MR is superior to CT for detection and characterization of brain and spine lesions.     

Evaluating medical students on radiology clerkships in a filmless environment: use of an electronic test prepared from PACS and digital teaching collection images

RATIONALE AND OBJECTIVES: The competency of medical students in radiology clerkships is traditionally evaluated with film images, projected slides of photographed films, or printed reproductions of films. As radiology departments switch to filmless imaging, it seemed appropriate to determine the feasibility of an electronic evaluation prepared directly from digital images. MATERIALS AND METHODS: The image-based portion of a multiple-choice final examination was prepared as a PowerPoint presentation that included images downloaded from the departmental picture archiving and communication system (PACS) or digital teaching collections. The images were downloaded as bitmap files, imported to Adobe Photoshop for image editing, converted to tagged image file format, and finally imported to PowerPoint, where they were combined with text to create 50 questions. A liquid crystal diode projector displayed the questions, with a timer set to advance them automatically. RESULTS: The examination was easy and inexpensive to prepare (no photography costs). In an initial survey of 25 students, 17 (71%) of 24 students rated the resolution of images as excellent and five (21%) as good. No student gave an image a poor rating. Students preferred that images cover at least 40%-50% of the slides, and most approved of a blue background. An original allowance of 30 seconds per slide was reported to be too fast; the interval was increased to 45 seconds. CONCLUSION: An electronic final examination for medical students, prepared with images downloaded from PACS or digital teaching collections, is feasible, easy to prepare, and cost-effective, and it provides an excellent display of test images.     

Effect of Electromagnetic Pulses (EMP) on associative learning in mice and a preliminary study of mechanism

Abstract

Purpose: To investigate the effects of electromagnetic pulses (EMP) on associative learning in mice and test a preliminary mechanism for these effects.

Materials and methods: A tapered parallel plate gigahertz transverse electromagnetic (GTEM) cell with a flared rectangular coaxial transmission line was used to expose male BALB/c mice to EMP (peak-intensity 400 kV/m, rise-time 10 ns, pulse-width 350 ns, 0.5 Hz and total 200 pulses). Concurrent sham-exposed mice were used as a control. Associative learning, oxidative stress in the brain, serum chemistry and the protective action of tocopherol monoglucoside (TMG) in mice were measured, respectively.

Results: (1) Twelve hour and 1 day post EMP exposure associative learning was reduced significantly compared with sham control (p < 0.05) but recovered at 2 d post EMP exposure. (2) Compared with the sham control, lipid peroxidation of brain tissue and chemiluminescence (CL) intensity increased significantly (p < 0.05), while the activity of the antioxidant enzymes Superoxide Dismutase [SOD], Glutathione [GSH], Glutathione Peroxidase [GSH-Px], Catalase [CAT]) decreased significantly (p < 0.05) at 3 h, 6 h, 12 h and 1 d post EMP exposure. All these parameters recovered at 2 d post EMP exposure. (3) No significant differences between the sham control group and EMP exposed group were observed in serum cholesterol and triglycerides. (4) Pretreatment of mice with TMG showed protective effects to EMP exposure.

Conclusions: EMP exposure significantly decreased associative learning in mice and TMG acted as an effective protective agent from EMP exposure. This mechanism could involve an increase of oxidative stress in brain by EMP exposure.     

肺栓塞的CT诊断及与深静脉血栓形成临床类型的相关性研究

目的:通过22例患者的CT诊断,探讨肺栓塞的影像学特征和病变特点,以及下肢深静脉血栓形成临床类型与肺栓塞发生之间内在的相关性,总结其发病规律,为合理应用预防和治疗措施提供依据。方法:肺部检查应用多层螺旋CT机,采用轴位像扫描,扫描层面从肺尖至肺底,均行强化,了解肺栓塞发生部位及特点。应用彩色多普勒超声诊断仪检查患肢深部和浅部静脉,主要观察静脉腔内有无血流、管壁结构及血栓状况。统计下肢深静脉血栓形成患者临床发病类型。结果:双侧肺栓塞者17例,右侧肺栓塞者4例,左侧肺栓塞者1例。病变累及部位涵盖主肺动脉至亚段动脉等各级肺动脉,肺栓塞直接征象以充盈缺损和附壁血栓最多见,间接征象以肺纹理稀疏、胸腔积液和肺梗死病灶出现率最高。肢体静脉彩色超声检出静脉血栓病变部位58处,股腘静脉血栓病变发生率为70.69%。临床类型属中央型者4例,混合型者13例,周围型者5例。结论:下肢深静脉血栓形成混合型病变发展血栓蔓延,新鲜血栓松软不稳定且与静脉壁附着不紧密而极易脱落造成肺栓塞。病变部位静脉管腔不完全闭塞及溶栓治疗过程,对肺栓塞的发生有一定影响。     

2017-2019年我国介入放射学工作人员眼晶状体剂量水平与分析

目的 调查2017-2019年我国介入放射学工作人员眼晶状体辐射剂量水平,掌握我国介入放射工作人员眼晶状体剂量水平现状.方法 通过国家个人剂量登记系统,采集我国28个省份介入放射学工作人员眼晶状体剂量监测数据,监测部位为左眼、评估指标为个人剂量当量Hp(3)、监测方法为热释光剂量计.分别运用Mann-Whitney U...     

Diffusion-weighted MRI of the prostate at 3.0 T: Comparison of endorectal coil (ERC) MRI and phased-array coil (PAC) MRI—The impact of SNR on ADC measurement

Purpose

To compare ADC values measured from diffusion-weighted MR (DW-MR) images of the prostate obtained with both endorectal and phased-array coils (ERC + PAC) to those from DW-MRI images obtained with an eight-channel torso phased-array coil (PAC) at 3.0 T.

Methods

The institutional review board issued a waiver of informed consent for this HIPAA-compliant study. Twenty-five patients with biopsy-proven prostate cancer underwent standard 3-T MRI using 2 different coil arrangements (ERC + PAC and PAC only) in the same session. DW-MRI at five b-values (0, 600, 1000, 1200, and 1500 s/mm²) were acquired using both coil arrangements. On b = 0 images, signal-to-noise ratios (SNRs) were measured as the ratio of the mean signal from PZ and TZ ROIs to the standard deviation from the mean signal in an artifact-free ROI in the rectum. Matching regions-of-interest (ROIs) were identified in the peripheral zone and transition zone on ERC-MRI and PAC-MRI. For each ROI, mean ADC values for all zero and non-zero b-value combinations were computed.

Results

Mean SNR with ERC-MRI at PZ (66.33 ± 27.07) and TZ (32.69 ± 12.52) was 9.27 and 5.52 times higher than with PAC-MRI ((7.32 ± 2.30) and (6.13 ± 1.56), respectively) (P < 0.0001 for both). ADCs from DW-MR images obtained with all b-values in the PZ and TZ were significantly lower with PAC-MRI than with ERC-MRI (P < 0.001 for all).

Conclusion

Lower SNR of DW-MR images of the prostate obtained with a PAC can significantly decrease ADC values at higher b-values compared to similar measurements obtained using the ERC. To address these requirements, clinical MR systems should have image processing capabilities which incorporate the noise distribution.     

CR与屏(铜)-片成像在头颈部肿瘤放疗射野影像验证中的比较应用

目的 评价计算机X线摄影(CR)与屏(铜)-片成像在头颈部肿瘤放疗射野影像验证中的应用价值.资料与方法 40张验证片中,20张采用传统屏(铜)-片摄影,20张采用CR摄影.由4名观察者分别对其进行评价,评价标准参照欧共体提供的影像标准,分"可见"、"再现"及"清晰再现"三级,取其平均百分比.采用SPSS 11.0统计软件包对观察者之间的一致性作方差分析.结果 CR的"可见"率为18.75%,"再现"率为71.25%,"清晰再现"率为10%;屏(铜)-片的"可见"率为71.25%,"再现"率为28.75%,"清晰再现"率为0.对比分析有意义的"再现"率与"清晰再现"率之和,CR组为81.25%,而屏(铜)-片组仅为28.75%.单因素方差分析结果显示观察者之间的一致性无统计学意义(P＞0.05).结论 CR成像在头颈部肿瘤放疗射野影像验证中较屏(铜)-片成像具有更好的显示效果.     

The role of Tc-99m (V) DMSA scintigraphy in the diagnosis and follow-up of lung cancer lesions

Objective To define the role of Tc-99m (V) dimercaptosuccinic acid (DMSA) scanning in the detection of lung cancer (LC) and its metastases, and monitoring the response of LC lesions (LCL) to chemo/radiotherapy (TH). Methods Tc-99m (V) DMSA whole-body scans, planar thorax views, and thorax Single-photon emission computed tomography (SPECT) images were obtained both 30 min (early) and 5 h (late) after Tc-99m (V) DMSA administration in 12 small/nonsmall cell LC patients (11 men, 1 woman; mean age 59 years). Five patients also had bone scans. The same scintigraphic protocol was performed in 7 of 12 patients, 3 weeks after first-line TH. TH response was evaluated visually in all LCL and semiquantitatively in primary tumors (PT) of six patients, by comparing the tumor uptake ratios (TUR) of pre-TH and post-TH Tc-99m (V) DMSA SPECT [TUR = mean counts of region of interests (ROI) in PT/mean counts in contralateral ROI]. In seven patients, a 6-month survival was determined. Results Tc-99m (V) DMSA accumulated in 34 LCL (11 PT, 19 bone metastases, 1 suprarenal mass, 1 axillary node, 2 supraclavicular nodes). A total of 11 patients displayed Tc-99m (V) DMSA uptake in LCL and one patient did not show uptake. In six patients, SPECT imaging showed deeply located PT in the lung parenchyma better than planar views. In five patients, both planar and SPECT views revealed peripherally located PT in the lungs. Early scans showed 18 LCL and late scans displayed all the LCL. Nine bone metastases on pre-TH Tc-99m (V) DMSA scans revealed matched areas of increased Tc-99m methylene diphosphonate (MDP) uptake on bone scans; six bone metastases were additionally detected on Tc-99m (V) DMSA scans when compared with bone scans, and four bone metastases on Tc-99m (V) DMSA scans could not be compared with bone scans because bone scan was not performed. In one patient, Tc-99m (V) DMSA scans became positive for bone metastases on post-TH later than the bone scans for some of the bone metastases. Neither planar nor SPECT imaging showed mediastinal lesions defined on thorax CT in nine patients. On TH monitoring, 17 LCL showed diminished Tc-99m (V) DMSA uptake, one disappeared, four were unchanged, three displayed increased uptake, and five new lesions were established. Of the six patients, TUR in PT increased in two (one survived), decreased in one (exitus), was unchanged in two (two exitus) on post-TH scans, and PT totally disappeared in one (survived) patient. Conclusions Tc-99m (V) DMSA scans are useful in detecting LCL, except for those around the blood pool regions, making it a promising modality to monitor TH response. Obtaining a single fifth hour late Tc-99m (V) DMSA scan is appropriate. SPECT should be applied to all patients for the detection of deeply located lesions.     

不同图像采集和处理对^67Ga显像质量及病灶探查的影响

目的分析平面显像、非衰减校正（NAC）断层显像和CT衰减校正（AC）断层显像等^67Ga显像图像采集和处理模式对图像质量和病灶判断的影响。方法用美国GE Millennium^TM VG 5型SPECT／CT仪对31例活动期肺结节病患者行^67Ga平面显像、胸部NAC断层显像;并对断层图像行CTAC。图像分析：双盲法阅片,判断平面图像、AC和NAC断层图像的图像质量及病灶数;测量病变与周围正常组织的放射性计数,并测量其比值。采用SPSS10．0软件,行配对t检验和,检验。结果图像质量按照平面显像、NAC、AC顺序依次提高（χ^2=25．880,P〈0．001）。以活动期结节病患者SPECT／CT示放射性增高的肺门、纵隔淋巴结为“病灶”,平面显像发现“病灶”70个,漏诊“病灶”8个;NAC、AC断层图像均发现“病灶”78个。NAC图像中“病灶”的放射性计数明显低于AC图像中“病灶”的放射性计数（15．240±8．865和67．241±35．049,t=-17．230,P〈0．001）。和NAC图像比较,AC图像“病灶”与肺的放射性比值增高（t=-7．520,P〈0．001）,“病灶”与肝（t=3．298,P=0．001）及“病灶”与腰椎（t=7,032,P〈0．001）的比值降低。结论^67Ga平面显像因前后组织放射性分布叠加,可能导致漏诊。^67Ga NAC断层显像能够较为准确地确定病变淋巴结的三维位置,但图像计数率低、噪声较大。AC断层图像虽未能增加检出的病灶数,但能有效提高NAC计数率,改善图像质量。     

甲状腺癌~(131)I显像假阳性的分析及鉴别诊断

:1 3 1 　 I显像是诊断分化型甲状腺转移癌的特异方法 ,有关报道显示该方法诊断甲状腺转移癌的特异性为 96 % ,灵敏度为 80 %。但近年来也有不少报道指出假阳性结果的存在 ,如额窦粘液囊肿、胸腺、肺癌、乳房、食道良性狭窄、结肠移植物、胃上移、肾囊肿等均可见有 1 3 1　 I的蓄积 ,尽管其发生率不高 ,但常干扰诊断 ,导致病员接受不必要的照射。因此 ,对假阳性结果的出现部位 ,产生原因及可能的鉴别方法应该有所了解。为了得到正确诊断 ,可合并应用其他影像诊断方法 ,或辅以 2 0 1　 Tl显像 ,或辅以测定血中人甲状腺球蛋白 ( h- TG) ,以利于用药     

The effect of brain tumor angiogenesis on the in vivo relationship between the gradient-echo relaxation rate change (DeltaR2*) and contrast agent (MION) dose

PURPOSE: To determine in vivo if the susceptibility calibration factor for gradient-echo imaging (k(G)), which characterizes the relationship between the tissue T2* relaxation rate change (DeltaR2*) and tissue contrast agent concentration, is independent of tissue type and condition; in addition, to assess the consequences of such an assumption on the use of relative cerebral blood volume (rCBV) measurements as a direct index of tumor angiogenesis. MATERIALS AND METHODS: The DeltaR2* was measured as a function of monocrystalline iron oxide nanoparticles (MION) contrast agent dose in a rat brain tumor (9L gliosarcoma) model, the blood volume fraction independently measured, and k(G) calculated and compared for the normal gray matter, normal white matter, tumor, and contralateral brain. RESULTS: The k(G) was found to be the same for gray and white matter (P = 0.53), but statistically different for tumor compared to contralateral brain (P = 0.005) with k(G(Tumor) ) < k(G(Brain) ) CONCLUSION: The gradient-echo calibration factor, k(G), is the same for brain gray and white matter, but not the same for brain and tumor tissue. This difference may be attributed to the grossly different vascular morphology of tumors, dueto tumor angiogenesis, compared to normal brain and/or possibly differing blood rheological factors such as hematocrit. Consequently, the sensitivity to blood volume differences between tumor and normal brain tissue may be lessened when using gradient-echo susceptibility contrast agent methods.     

系统性红斑狼疮的心脏X线与病理对照分析（附8例报告）

本文报告系统性红斑狼疮（简称ＳＬＥ）８例，均做了尸体解剖检查并发现心、肺和肾等多脏器损害。全部病例的心脏临床表现均较病理改变轻微，其中两例Ｘ线未发现心脏及肺循环异常。心脏增大的病理基础是ＳＬＥ侵及心脏全层与心包；高血压是导致心脏增大的另一个主要因素。左心衰竭产生肺静脉高压；胸部病变及肺小动脉玻璃样变性可导致肺动脉高压。