内容紹介
低線量被ばくによる健康への影響は科学的に解明されていないものの、検診目的の大腸CTの課題は医療被ばくである。健康な成人を対象とする大腸CTでは、十分な知識のもとなるべく低線量で撮影されなければならない。(超)低線量大腸CTに有用な方法は、自動露出機構を活用した低管電流撮影である。低線量化に伴って増加する画像のノイズに対しては、逐次近似(応用)再構成が有用であり積極的な活用が望まれる。さらなる低線量化のために、低管電圧の有効性も示唆されている。
Although the true risk of very low levels of intermittent radiation is unknown, one of the main weaknesses of the screening CT colonography is the exposure to radiation. Radiation exposure must be kept to a minimum in CT colonography for health subjects. Reducing the tube current and using automatic exposure control are the simplest method to effectively reduce radiation dose. Iterative reconstruction algorithms also play an important role in the dose reduction by decreasing the amount of quantum noise. In addition, decreased tube voltage may be useful in CT colonography to further reduce radiation dose.
目次
Although the true risk of very low levels of intermittent radiation is unknown, one of the main weaknesses of the screening CT colonography is the exposure to radiation. Radiation exposure must be kept to a minimum in CT colonography for health subjects. Reducing the tube current and using automatic exposure control are the simplest method to effectively reduce radiation dose. Iterative reconstruction algorithms also play an important role in the dose reduction by decreasing the amount of quantum noise. In addition, decreased tube voltage may be useful in CT colonography to further reduce radiation dose.