我国法律法规中犯罪嫌疑人实施犯罪时是否年满18周岁是作为从轻减、轻刑事责任甚至免除死刑的重要年龄节点。传统影像学评价所选取的左手部腕骨、四肢大关节长骨端骨骺等指标在18周岁骨龄推测中价值明显减弱。本课题旨在构建适合当代四川18周岁汉族青少年骨龄评价指标体系。选取在18周岁左右骨骺仍未完全停止生长仅有的少数的部位- - 锁骨胸骨端、骨盆的髂嵴-坐骨结节、下颌第三磨牙作为观测指标，分别运用薄层CT、数字X线片、OPG对锁骨胸骨端、骨盆髂嵴-坐骨结节、下颌第三磨牙摄片，并建立相应骨骺发育分级标准。通过大样本数据构建推测活体骨龄的多元回归数学模型、是否已满18周岁的Fisher's判别方程，同时首次引入ROC曲线分析法对该指标体系效能进行评估。本课题成果是我国法医影像学评价骨龄的新突破，可以预见将为刑事案件侦查和审判提供有力技术支持，具有较高科学价值。

18 years as the age of relevance to criminal liability or even eliminate the death penalty. has significant meaning in Chinese law. In traditional forensic radiology, the Observation index used in living body age estimation (such as the left carpal bones and the teeth excluding the third molars) have little practical significance as they stop growing or developing at 18 years of age. The aim of this study is to establish an age estimation index system which is suitable for contemporary Sichuan Han teenagers of 18 years. The third molar, medial epiphyses of the clavicle and pelvic epiphyses are still developing after 18 years old, we choose the OPG, CT and X-ray to observe the three anatomical growth markers. Through the analysis of these living sample images data , we will establish the multiple regression mathematical model to estimation the age of living teenagers; establish two kinds of equations for Fisher's discriminant analysis to discriminate between individuals who were or were not at age 18 years or more. The receiver operating characteristic (ROC) curve will also be introduced to assess the effectiveness of the age estimation system. Eventually we will make the standard development map of the 15-21 years old youth every half year old as a group to observe the youth's development . The result of this study is a breakthrough of age estimation by radiography in china.It is easily to foresee the powerful support that may arise from this study in Criminal case investigation and criminal justice.

18周岁是司法审判是否承担刑事责任重要的年龄节点，准确地推断犯罪嫌疑人是否满18周岁，是目前法医临床学研究与实践的重点之一。骨骼的骨骺愈合程度和牙齿发育特征是推断青少年年龄的重要手段，影像技术的应用实现了活体骨龄鉴定。手/腕骨是骨龄测定最常用的拍摄部位，但在18周岁年龄推断中的应用价值不大。本研究基于前期研究基础，应用多元影像学手段观察锁骨胸骨端、骨盆、膝关节和第三磨牙的发育特征，以期筛选适用于18周岁年龄推断的指标。本研究观察锁骨胸骨端CT、骨盆X线片、第三磨牙全颌曲面断层片以及膝关节X线片和MRI的发育和成像特点，构建了适合当代中国汉族人群18周岁青少年骨龄（包括牙龄）的评价指标体系。主要研究内容及结果如下：①分析上述骨骼骨骺发育特征及下颌第三磨牙发育特征，绘制了各指标发育标准图谱。②分析各指标随年龄变化特点，绘制了各指标累积分布函数图，发现锁骨胸骨端可用于18周岁的判断。③分别建立了各指标年龄推断模型。④建立了第三磨牙推断18周岁的判别分析，ROC曲线提示骨盆、第三磨牙和膝关节在18周岁推断中有重要价值。本研究结果显示上述指标均可用于18岁年龄推断。上述研究为刑事责任年龄的鉴定提供了技术支撑，为司法审判提供依据，部分研究结果已用于法医学实践工作。