Carstensen E L
Department of Electrical Engineering, University of Rochester, NY 14627.
Ultrasound Med Biol. 1987 Oct;13(10):597-606. doi: 10.1016/0301-5629(87)90057-3.
A massive body of screening studies attests to the safety of diagnostic ultrasound. It appears that further progress in analysis of the safety question, will require mechanistic guidance. In theory, transient cavitation can occur under diagnostically relevant conditions if appropriate nuclei exist in the exposed medium. Low-temporal-average-intensity, pulsed ultrasound equivalent to that used in diagnosis has been shown to cause deleterious effects in lower organisms. All available evidence supports the conclusion that these effects are mediated by acoustic cavitation. It is impossible to extrapolate from these observations to human beings. However, all of the information available to us at the present time suggests that if transient cavitation occurs under diagnostic conditions, the events are rare, highly localized and probably would be of minor importance in almost any part of the body with the possible exception of the developing embryo or fetus. Transient cavitation is characterized by sharply defined thresholds. If future studies demonstrate the occurrence of cavitation related effects, they can be eliminated simply by keeping the maximum pressure amplitudes below those thresholds.
大量的筛查研究证明了诊断性超声的安全性。看来，要在安全性问题分析上取得进一步进展，需要机制指导。理论上，如果暴露介质中存在合适的核，在与诊断相关的条件下可能会发生瞬态空化。已证明，与诊断中使用的等效的低时间平均强度脉冲超声会对低等生物造成有害影响。所有现有证据都支持这些影响是由声空化介导的这一结论。从这些观察结果推断人类情况是不可能的。然而，目前我们所掌握的所有信息表明，如果在诊断条件下发生瞬态空化，这种情况很少见，高度局限，而且在身体的几乎任何部位可能都不太重要，发育中的胚胎或胎儿可能除外。瞬态空化的特点是阈值明确。如果未来的研究证明存在与空化相关的影响，只需将最大压力幅度保持在这些阈值以下就可以消除这些影响。
