People engaged in heavy manual labor have higher X-ray detective rates than others engaged in light manual labor. 从事过重体力劳动者骨皮质增厚的X线检出率高于从事轻体力劳动者;
However, there are a range of issues for manual testing, such as high cost, low efficiency, high error rates and un-conduciveness to pipeline production, and so on. 人工检测会带来高成本、低效率、高错误率和不利于生产流水线化等一系列问题。