目的探讨儿童腺样体低剂量CT扫描的表现并对其图像质量进行初步分析,以减少儿童X射线检查的辐射剂量,协助临床诊断。方法分析100例临床怀疑腺样体肥大儿童。分2组,50例使用低剂量:60~80 k V,50例使用常规剂量:80~120 k V。所有患者均分...目的探讨儿童腺样体低剂量CT扫描的表现并对其图像质量进行初步分析,以减少儿童X射线检查的辐射剂量,协助临床诊断。方法分析100例临床怀疑腺样体肥大儿童。分2组,50例使用低剂量:60~80 k V,50例使用常规剂量:80~120 k V。所有患者均分析不同CT剂量的图像对其腺样体的显示情况。结果检查患者中CT表现为腺样体肥大的占94例,占94%,常规剂量患者得到信噪比较高图像,但所接受射线量较大。低剂量扫描大大地减少了儿童的辐射剂量,图像均能达到临床诊断要求。结论低剂量CT检查能准确显示儿童腺样体的肥大程度并对其作出诊断,为临床提供足够的影像学依据。展开更多
Objective:The main purpose of this work was to present a Z-phantom manufactured in home (at National Cancer Institute Cairo University) and it's use in a simple way to check the accuracy of the computed-tomography...Objective:The main purpose of this work was to present a Z-phantom manufactured in home (at National Cancer Institute Cairo University) and it's use in a simple way to check the accuracy of the computed-tomography (CT) table movement and CT gantry tilt, also the other general quality control (QC) tests of the CT simulator used at radiotherapy department. Methods:The laser phantom was used to check the external mobile laser position accuracy, for internal image indicator laser beam (light field) the coincidence between light field and radiation exposure at CT simulator was checked using X-Omat ready back film. The Z-phantom was used to check the slice thickness and the table movement and so the gantry tilts. The image quality testes were checked using the CT image quality phantom. TLDs were inserted to the Cicil phantom at the center of each scan volume to estimate the patient dose. Results:The results showed that the difference in the fixed distance between the external mobile laser and the internal image indicator laser beam was less than ± 1 mm; the orientation of the two mobile lateral lasers was coincident. The mechanical movement and the image quality of the CT simulator were within the tolerances and the results were 0.5 mm, 0.2% and 0.6% for the mechanical movement, noise and image uniformity respectively. Conclusion:A CT simulator with a good performance is important for the radiotherapy treatment planning specially with the extremely revolution in radiotherapy techniques, also a rotten quality assurance (QA) program is very important to be shore about the reproducibility of the CT performance. The use of Z-phantom to check the gantry tilt and the table movement is faster than the use of ready back films in these tests.展开更多
Dual-energy computed-tomography(DECT) has been suggested as the method of choice for imaging urinary calculi due to the modality's high sensitivity for detect-ing stones and its capability of accurately differenti...Dual-energy computed-tomography(DECT) has been suggested as the method of choice for imaging urinary calculi due to the modality's high sensitivity for detect-ing stones and its capability of accurately differentiat-ing between uric-acid(UA) and non-UA(predominantly calcium) stones. The clinical significance of the latter feature relates to the differences in management of UA vs non-UA calculi. Like calculi, ureteral stents are assigned color by the dual-energy post-processing algorithm, which may lead to improved or worsened stone visualization based on the resulting stent/stone contrast. Herein we depict the case of a nephrolithiasis patient with bilateral stents, each with different color, clearly displaying the effect of stent color on stone vi-sualization. Further, three-dimensional reconstruction of the DECT images illustrates advantages of this enhancement compared to conventional two-dimensional computed tomography. The resulting stent/stone contrast produces an unanticipated potential advantage of DECT in patients with urolithiasis and stents and may promote improved management decision-making.展开更多
文摘目的探讨儿童腺样体低剂量CT扫描的表现并对其图像质量进行初步分析,以减少儿童X射线检查的辐射剂量,协助临床诊断。方法分析100例临床怀疑腺样体肥大儿童。分2组,50例使用低剂量:60~80 k V,50例使用常规剂量:80~120 k V。所有患者均分析不同CT剂量的图像对其腺样体的显示情况。结果检查患者中CT表现为腺样体肥大的占94例,占94%,常规剂量患者得到信噪比较高图像,但所接受射线量较大。低剂量扫描大大地减少了儿童的辐射剂量,图像均能达到临床诊断要求。结论低剂量CT检查能准确显示儿童腺样体的肥大程度并对其作出诊断,为临床提供足够的影像学依据。
文摘Objective:The main purpose of this work was to present a Z-phantom manufactured in home (at National Cancer Institute Cairo University) and it's use in a simple way to check the accuracy of the computed-tomography (CT) table movement and CT gantry tilt, also the other general quality control (QC) tests of the CT simulator used at radiotherapy department. Methods:The laser phantom was used to check the external mobile laser position accuracy, for internal image indicator laser beam (light field) the coincidence between light field and radiation exposure at CT simulator was checked using X-Omat ready back film. The Z-phantom was used to check the slice thickness and the table movement and so the gantry tilts. The image quality testes were checked using the CT image quality phantom. TLDs were inserted to the Cicil phantom at the center of each scan volume to estimate the patient dose. Results:The results showed that the difference in the fixed distance between the external mobile laser and the internal image indicator laser beam was less than ± 1 mm; the orientation of the two mobile lateral lasers was coincident. The mechanical movement and the image quality of the CT simulator were within the tolerances and the results were 0.5 mm, 0.2% and 0.6% for the mechanical movement, noise and image uniformity respectively. Conclusion:A CT simulator with a good performance is important for the radiotherapy treatment planning specially with the extremely revolution in radiotherapy techniques, also a rotten quality assurance (QA) program is very important to be shore about the reproducibility of the CT performance. The use of Z-phantom to check the gantry tilt and the table movement is faster than the use of ready back films in these tests.
文摘Dual-energy computed-tomography(DECT) has been suggested as the method of choice for imaging urinary calculi due to the modality's high sensitivity for detect-ing stones and its capability of accurately differentiat-ing between uric-acid(UA) and non-UA(predominantly calcium) stones. The clinical significance of the latter feature relates to the differences in management of UA vs non-UA calculi. Like calculi, ureteral stents are assigned color by the dual-energy post-processing algorithm, which may lead to improved or worsened stone visualization based on the resulting stent/stone contrast. Herein we depict the case of a nephrolithiasis patient with bilateral stents, each with different color, clearly displaying the effect of stent color on stone vi-sualization. Further, three-dimensional reconstruction of the DECT images illustrates advantages of this enhancement compared to conventional two-dimensional computed tomography. The resulting stent/stone contrast produces an unanticipated potential advantage of DECT in patients with urolithiasis and stents and may promote improved management decision-making.
