Cone-beam CT (CBCT) images acquired during radiation treatment can be used to recalculate the dose distribution as well as to confirm the treatment location. However, it is difficult to obtain the electron densities (...Cone-beam CT (CBCT) images acquired during radiation treatment can be used to recalculate the dose distribution as well as to confirm the treatment location. However, it is difficult to obtain the electron densities (EDs) necessary for dose calculation from CBCT images because of the effects of scatter contamination during CBCT image acquisition. This paper presents a mathematical method for converting the pixel values of CBCT images (CBCT values) into Hounsfield units (HUs) of radiation treatment simulation CT (simCT) images for use in radiation treatment planning. CBCT values are converted into HUs by matching the histograms of the CBCT values with the histograms of the HUs for each slice via linear scaling of the CBCT values. For prostate cancer and head-and-neck cancer patients, the EDs obtained from converted CBCT values (mCBCT values) show good agreement with the EDs obtained from HUs, within approximately 3.0%, and the dose calculated on the basis of CBCT images shows good agreement with the dose calculated on the basis of the simCT images, within approximately 2.0%. Because the CBCT values are converted for each slice, this conversion method can account for variation in the CBCT values associated with differences in body size, body shape, and inner tissue structures, as well as in longitudinally displaced positions from the isocenter, unlike conventional methods that use electron density phantoms. This method improves on conventional CBCT-ED conversion and shows considerable potential for improving the accuracy of radiation treatment planning using CBCT images.展开更多
Objective To establish and evaluate two protocols for the noninvasive visualization and assessment of coronary artery bypass graft (CABG) patency on electron beam tomography (EBT).Methods Two hundred and fourteen cons...Objective To establish and evaluate two protocols for the noninvasive visualization and assessment of coronary artery bypass graft (CABG) patency on electron beam tomography (EBT).Methods Two hundred and fourteen consecutive patients who underwent coronary artery bypass graft surgery were scanned using both EBT angiography with 3-dimensional reconstruction and EBT flow study with time-density-curve analysis.Results There were 589 CABGs evaluated in this study (10 grafts were excluded because of artifacts). Among them, 133 (98.5％) of 135 arterial grafts were patent, and 345 (77.7％) of 444 saphenous-vein grafts were patent. Within 5 years or between 5 and 10 years after operation, arterial graft patency exceeded venous graft patency (P ＜ 0.001 ). Three-dimensional EBT angiography achieved higher sensitivity, specificity and accuracy (97.7％, 94.1％ and 96.7％, respectively) than did EBT flow study (88.4％, 82.4％ and 85.2％, respectively) for evaluating occlusion or patency of CABG. The intra-graft flow of patent arterial and venous grafts were 4.9 ± 2.2 mi · min-1 · g-1 and 6.9 ± 2.8 mi · min-1 · g-1,respectively (P＜0.001).Conclusion The combination of EBT three-dimensional reconstruction and flow study can be more effective in the assessment of CABG anatomy and quantification of patent CABG blood flow.展开更多
目的观察锥形束电子计算机断层扫描(CBCT)联合超声骨刀微创法治疗儿童上颌埋伏多生牙的临床疗效。方法回顾性分析电子科技大学医学院附属妇女儿童医院(成都市妇女儿童中心医院)2021年1月至2023年1月入院的60例上颌埋伏多生牙患儿,根据...目的观察锥形束电子计算机断层扫描(CBCT)联合超声骨刀微创法治疗儿童上颌埋伏多生牙的临床疗效。方法回顾性分析电子科技大学医学院附属妇女儿童医院(成都市妇女儿童中心医院)2021年1月至2023年1月入院的60例上颌埋伏多生牙患儿,根据治疗方式不同将其分为研究组(n=30)与对照组(n=30)。两组患儿均接受锥形束CT检查,研究组行超声骨刀手术治疗,对照组行电动式颌面外科微动力手术治疗。比较两组患者的围术期指标(出血量、手术时间、手术成功率、出院时间)、术后牙齿松动度、张口度、疼痛评分[视觉模拟评分法(VAS)]及并发症(麻醉注射反应、面部肿胀、鼻腔出血)发生率。结果两组患儿的手术时间、手术成功率比较,差异均无统计学意义(P>0.05);研究组患儿出血量、出院时间分别为(2.15±1.18)mL、(24.47±3.25)h,分别低(短)于对照组[(12.42±5.03)mL、(34.79±4.23)h],差异均有统计学意义(P<0.05)。研究组患儿的牙齿松动总发生率为46.67%,明显低于对照组(73.33%),差异有统计学意义(P<0.05)。研究组患儿术后1、3、7 d张口度依次为(9.01±1.27)、(17.03±3.71)、(22.49±4.28)mm,均大于对照组[(8.19±1.18)、(15.06±3.37)、(20.25±3.81)mm],差异均有统计学意义(P<0.05)。研究组患儿术后1、3、7 d VAS评分依次为(5.39±0.68)、(3.25±0.49)、(1.24±0.28)分,均明显低于对照组[(5.81±0.62)、(3.71±0.53)、(1.71±0.31)分],差异均有统计学意义(P<0.05)。两组患儿术后总并发症发生率比较,差异无统计学意义(P>0.05)。结论CBCT联合超声骨刀微创法治疗儿童上颌埋伏多生牙的临床疗效显著,可有效减少患儿手术创伤及疼痛程度,降低牙齿松动度发生风险,扩大张口度,且并发症少,安全性高。展开更多
文摘Cone-beam CT (CBCT) images acquired during radiation treatment can be used to recalculate the dose distribution as well as to confirm the treatment location. However, it is difficult to obtain the electron densities (EDs) necessary for dose calculation from CBCT images because of the effects of scatter contamination during CBCT image acquisition. This paper presents a mathematical method for converting the pixel values of CBCT images (CBCT values) into Hounsfield units (HUs) of radiation treatment simulation CT (simCT) images for use in radiation treatment planning. CBCT values are converted into HUs by matching the histograms of the CBCT values with the histograms of the HUs for each slice via linear scaling of the CBCT values. For prostate cancer and head-and-neck cancer patients, the EDs obtained from converted CBCT values (mCBCT values) show good agreement with the EDs obtained from HUs, within approximately 3.0%, and the dose calculated on the basis of CBCT images shows good agreement with the dose calculated on the basis of the simCT images, within approximately 2.0%. Because the CBCT values are converted for each slice, this conversion method can account for variation in the CBCT values associated with differences in body size, body shape, and inner tissue structures, as well as in longitudinally displaced positions from the isocenter, unlike conventional methods that use electron density phantoms. This method improves on conventional CBCT-ED conversion and shows considerable potential for improving the accuracy of radiation treatment planning using CBCT images.
文摘Objective To establish and evaluate two protocols for the noninvasive visualization and assessment of coronary artery bypass graft (CABG) patency on electron beam tomography (EBT).Methods Two hundred and fourteen consecutive patients who underwent coronary artery bypass graft surgery were scanned using both EBT angiography with 3-dimensional reconstruction and EBT flow study with time-density-curve analysis.Results There were 589 CABGs evaluated in this study (10 grafts were excluded because of artifacts). Among them, 133 (98.5％) of 135 arterial grafts were patent, and 345 (77.7％) of 444 saphenous-vein grafts were patent. Within 5 years or between 5 and 10 years after operation, arterial graft patency exceeded venous graft patency (P ＜ 0.001 ). Three-dimensional EBT angiography achieved higher sensitivity, specificity and accuracy (97.7％, 94.1％ and 96.7％, respectively) than did EBT flow study (88.4％, 82.4％ and 85.2％, respectively) for evaluating occlusion or patency of CABG. The intra-graft flow of patent arterial and venous grafts were 4.9 ± 2.2 mi · min-1 · g-1 and 6.9 ± 2.8 mi · min-1 · g-1,respectively (P＜0.001).Conclusion The combination of EBT three-dimensional reconstruction and flow study can be more effective in the assessment of CABG anatomy and quantification of patent CABG blood flow.
文摘目的观察锥形束电子计算机断层扫描(CBCT)联合超声骨刀微创法治疗儿童上颌埋伏多生牙的临床疗效。方法回顾性分析电子科技大学医学院附属妇女儿童医院(成都市妇女儿童中心医院)2021年1月至2023年1月入院的60例上颌埋伏多生牙患儿,根据治疗方式不同将其分为研究组(n=30)与对照组(n=30)。两组患儿均接受锥形束CT检查,研究组行超声骨刀手术治疗,对照组行电动式颌面外科微动力手术治疗。比较两组患者的围术期指标(出血量、手术时间、手术成功率、出院时间)、术后牙齿松动度、张口度、疼痛评分[视觉模拟评分法(VAS)]及并发症(麻醉注射反应、面部肿胀、鼻腔出血)发生率。结果两组患儿的手术时间、手术成功率比较,差异均无统计学意义(P>0.05);研究组患儿出血量、出院时间分别为(2.15±1.18)mL、(24.47±3.25)h,分别低(短)于对照组[(12.42±5.03)mL、(34.79±4.23)h],差异均有统计学意义(P<0.05)。研究组患儿的牙齿松动总发生率为46.67%,明显低于对照组(73.33%),差异有统计学意义(P<0.05)。研究组患儿术后1、3、7 d张口度依次为(9.01±1.27)、(17.03±3.71)、(22.49±4.28)mm,均大于对照组[(8.19±1.18)、(15.06±3.37)、(20.25±3.81)mm],差异均有统计学意义(P<0.05)。研究组患儿术后1、3、7 d VAS评分依次为(5.39±0.68)、(3.25±0.49)、(1.24±0.28)分,均明显低于对照组[(5.81±0.62)、(3.71±0.53)、(1.71±0.31)分],差异均有统计学意义(P<0.05)。两组患儿术后总并发症发生率比较,差异无统计学意义(P>0.05)。结论CBCT联合超声骨刀微创法治疗儿童上颌埋伏多生牙的临床疗效显著,可有效减少患儿手术创伤及疼痛程度,降低牙齿松动度发生风险,扩大张口度,且并发症少,安全性高。
