Department of Medical Physics and Engineering, Osaka University Graduate School of Medicine, Yamadaoka 1-7, Suita-shi, Osaka 565-0871, Japan.
Phys Med Biol. 2011 Oct 7;56(19):6279-89. doi: 10.1088/0031-9155/56/19/008. Epub 2011 Sep 6.
Respiratory gating radiotherapy is used to irradiate a local area and to reduce normal tissue toxicity. There are certain methods for the detection of tumor motions, for example, using internal markers or an external respiration signal. However, because some of these respiratory monitoring systems require special or expensive equipment, respiratory monitoring can usually be performed only in limited facilities. In this study, the feasibility of using an acceleration sensor for respiratory monitoring was evaluated. The respiratory motion was represented by means of a platform and measured five times with the iPod touch® at 3, 4 and 5 s periods of five breathing cycles. For these three periods of the reference waveform, the absolute means ± standard deviation (SD) of displacement were 0.45 ± 0.34 mm, 0.33 ± 0.24 mm and 0.31 ± 0.23 mm, respectively. On the other hand, the corresponding absolute means ± SD for the periods were 0.04 ± 0.09 s, 0.04 ± 0.02 s and 0.06 ± 0.04 s. The accuracy of respiratory monitoring using the acceleration sensor was satisfactory in terms of the absolute means ± SD. Using the iPod touch® for respiratory monitoring does not need special equipment and makes respiratory monitoring easier. For these reasons, this system is a viable alternative to other respiratory monitoring systems.
呼吸门控放射治疗用于照射局部区域并降低正常组织毒性。有一些检测肿瘤运动的方法，例如使用内部标记物或外部呼吸信号。然而，由于这些呼吸监测系统中的一些需要特殊或昂贵的设备，因此通常只能在有限的设施中进行呼吸监测。在这项研究中，评估了使用加速度传感器进行呼吸监测的可行性。呼吸运动通过平台表示，并使用 iPod touch®在五次呼吸周期的 3、4 和 5 秒周期中五次测量。对于参考波形的这三个时间段，位移的绝对平均值±标准偏差 (SD) 分别为 0.45±0.34mm、0.33±0.24mm 和 0.31±0.23mm。另一方面，相应的绝对平均值±SD 分别为 0.04±0.09s、0.04±0.02s 和 0.06±0.04s。从绝对平均值±SD 的角度来看，使用加速度传感器进行呼吸监测的准确性令人满意。使用 iPod touch®进行呼吸监测不需要特殊设备，使呼吸监测更容易。基于这些原因，该系统是其他呼吸监测系统的可行替代方案。
