PDF(Pubmed)
Abstract：
BACKGROUND: Pediatric molecular imaging requires a balance between administering an activity that will yield sufficient diagnostic image quality while maintaining patient radiation exposure at acceptable levels. In current clinical practice, this balance is arrived at by the current North American Consensus Guidelines in which patient weight is used to recommend the administered activity (AA).
OBJECTIVE: We have previously demonstrated that girth (waist circumference at the level of the kidneys) is better at equalizing image quality than patient weight for pediatric Tc-99m DMSA renal function imaging. However, the correlation between image quality (IQ), AA, and patient girth has not been rigorously and systematically developed. In this work, we generate a series of curves showing the tradeoff between AA and IQ as a function of patient girth, providing the data for standards bodies to develop the next generation of dosing guideline for pediatric DMSA SPECT.
METHODS: An anthropomorphic phantom series that included variations in age (5, 10, and 15 years), gender (M, F), local body morphometry (5, 10, 50, 90, and 95th girth percentiles), and kidney size (±15% standard size), was used to generate realistic SPECT projections. A fixed and clinically challenging defect-to-organ volume percentage (0.49% of renal cortex value) was used to model a focal defect with zero uptake (i.e., full local loss of renal function). Task-based IQ assessment methods were used to rigorously measure IQ in terms of renal perfusion defect detectability. This assessment was performed at multiple count levels (corresponding to various AAs) for groups of patients that had similar girths and defect sizes. Receiver-operating characteristics (ROC) analysis was applied; the area under the ROC curve (AUC) was used as a figure-of-merit for task performance. Curves showing the tradeoff between AUC and AA were generated for these groups of phantoms.
RESULTS: Overall, the girth-based dosing method suggested different amounts of AA compared to weight-based dosing for the phantoms that had a relatively large body weight but a small girth or phantoms with relatively small bodyweight but large girth. Reductions of AA to 62.9% compared to weight-based dosing guidelines can potentially be realized while maintaining a baseline (AUC = 0.80) IQ for certain 15-year-olds who have a relatively small girth and large defect size. Note that the task-based IQ results are heavily dependent on the simulated defect size for the defect detection task and the appropriate AUC value must be decided by the physicians for this diagnostic task. These results are based purely on simulation and are subject to future clinical validation.
CONCLUSIONS: The study provides simulation-based IQ-AA data for a girth-based dosing method for pediatric renal SPECT, suggesting that patient waist circumference at the level of kidneys should be considered in selecting the AA needed to achieve an acceptable IQ. This data may be useful for standards bodies to develop girth-based dosing guidelines.
OBJECTIVE: We have previously demonstrated that girth (waist circumference at the level of the kidneys) is better at equalizing image quality than patient weight for pediatric Tc-99m DMSA renal function imaging. However, the correlation between image quality (IQ), AA, and patient girth has not been rigorously and systematically developed. In this work, we generate a series of curves showing the tradeoff between AA and IQ as a function of patient girth, providing the data for standards bodies to develop the next generation of dosing guideline for pediatric DMSA SPECT.
METHODS: An anthropomorphic phantom series that included variations in age (5, 10, and 15 years), gender (M, F), local body morphometry (5, 10, 50, 90, and 95th girth percentiles), and kidney size (±15% standard size), was used to generate realistic SPECT projections. A fixed and clinically challenging defect-to-organ volume percentage (0.49% of renal cortex value) was used to model a focal defect with zero uptake (i.e., full local loss of renal function). Task-based IQ assessment methods were used to rigorously measure IQ in terms of renal perfusion defect detectability. This assessment was performed at multiple count levels (corresponding to various AAs) for groups of patients that had similar girths and defect sizes. Receiver-operating characteristics (ROC) analysis was applied; the area under the ROC curve (AUC) was used as a figure-of-merit for task performance. Curves showing the tradeoff between AUC and AA were generated for these groups of phantoms.
RESULTS: Overall, the girth-based dosing method suggested different amounts of AA compared to weight-based dosing for the phantoms that had a relatively large body weight but a small girth or phantoms with relatively small bodyweight but large girth. Reductions of AA to 62.9% compared to weight-based dosing guidelines can potentially be realized while maintaining a baseline (AUC = 0.80) IQ for certain 15-year-olds who have a relatively small girth and large defect size. Note that the task-based IQ results are heavily dependent on the simulated defect size for the defect detection task and the appropriate AUC value must be decided by the physicians for this diagnostic task. These results are based purely on simulation and are subject to future clinical validation.
CONCLUSIONS: The study provides simulation-based IQ-AA data for a girth-based dosing method for pediatric renal SPECT, suggesting that patient waist circumference at the level of kidneys should be considered in selecting the AA needed to achieve an acceptable IQ. This data may be useful for standards bodies to develop girth-based dosing guidelines.
摘要：
背景：儿科分子成像需要在给予将产生足够诊断图像质量的活动与维持患者辐射暴露在可接受水平之间的平衡。在目前的临床实践中，这一平衡是根据当前的《北美共识指南》达成的,在该指南中,患者体重用于推荐给药活动(AA).
目的：我们以前已经证明，对于儿童Tc-99mDMSA肾功能成像，周长（肾脏水平的腰围）比患者体重更好地平衡图像质量。然而,图像质量(IQ)之间的相关性，AA,病人的周长还没有得到严格和系统的发展。在这项工作中,我们生成一系列曲线，显示AA和IQ之间的权衡作为患者围长的函数，为标准机构提供数据，以制定下一代儿科DMSASPECT给药指南。
方法：包含年龄变化（5、10和15岁）的拟人化幻影系列，性别(M,F),局部身体形态测量(5、10、50、90和第95个周长百分位数)，和肾脏大小（±15％标准大小），用于生成逼真的SPECT投影。使用固定且具有临床挑战性的缺陷与器官体积的百分比（肾皮质值的0.49％）来模拟零摄取的局灶性缺陷（即，肾功能完全局部丧失)。基于任务的智商评估方法用于严格测量肾脏灌注缺陷可检测性的智商。对于具有相似周长和缺损大小的患者组,在多个计数水平(对应于各种AA)下进行该评估。应用接受者工作特征（ROC）分析；ROC曲线下面积（AUC）用作任务执行的优值。对于这些体模组,产生显示AUC和AA之间的折衷的曲线。
结果：总体而言，对于体重相对较大但周长较小的体模或体重相对较小但周长较大的体模，基于周长的给药方法建议使用不同的AA量。与基于体重的给药指南相比，AA降低到62.9％可能会实现，同时保持基线（AUC=0.80）IQ对于某些15岁的人来说，周长相对较小，缺陷较大。请注意，基于任务的IQ结果在很大程度上取决于缺陷检测任务的模拟缺陷大小，并且医师必须为此诊断任务决定适当的AUC值。这些结果纯粹基于模拟，并有待未来的临床验证。
结论：该研究提供了基于模拟的IQ-AA数据，用于小儿肾SPECT的基于围长的给药方法，建议在选择达到可接受IQ所需的AA时，应考虑肾脏水平的患者腰围。该数据对于标准机构制定基于围长的给药指南可能是有用的。
目的：我们以前已经证明，对于儿童Tc-99mDMSA肾功能成像，周长（肾脏水平的腰围）比患者体重更好地平衡图像质量。然而,图像质量(IQ)之间的相关性，AA,病人的周长还没有得到严格和系统的发展。在这项工作中,我们生成一系列曲线，显示AA和IQ之间的权衡作为患者围长的函数，为标准机构提供数据，以制定下一代儿科DMSASPECT给药指南。
方法：包含年龄变化（5、10和15岁）的拟人化幻影系列，性别(M,F),局部身体形态测量(5、10、50、90和第95个周长百分位数)，和肾脏大小（±15％标准大小），用于生成逼真的SPECT投影。使用固定且具有临床挑战性的缺陷与器官体积的百分比（肾皮质值的0.49％）来模拟零摄取的局灶性缺陷（即，肾功能完全局部丧失)。基于任务的智商评估方法用于严格测量肾脏灌注缺陷可检测性的智商。对于具有相似周长和缺损大小的患者组,在多个计数水平(对应于各种AA)下进行该评估。应用接受者工作特征（ROC）分析；ROC曲线下面积（AUC）用作任务执行的优值。对于这些体模组,产生显示AUC和AA之间的折衷的曲线。
结果：总体而言，对于体重相对较大但周长较小的体模或体重相对较小但周长较大的体模，基于周长的给药方法建议使用不同的AA量。与基于体重的给药指南相比，AA降低到62.9％可能会实现，同时保持基线（AUC=0.80）IQ对于某些15岁的人来说，周长相对较小，缺陷较大。请注意，基于任务的IQ结果在很大程度上取决于缺陷检测任务的模拟缺陷大小，并且医师必须为此诊断任务决定适当的AUC值。这些结果纯粹基于模拟，并有待未来的临床验证。
结论：该研究提供了基于模拟的IQ-AA数据，用于小儿肾SPECT的基于围长的给药方法，建议在选择达到可接受IQ所需的AA时，应考虑肾脏水平的患者腰围。该数据对于标准机构制定基于围长的给药指南可能是有用的。
