BIOEFFECTS OF GAS BODY ACTIVATION IN MEDICAL ULTRASOUND

描述：（改编自研究者摘要） 的演变 医疗超声需要对安全问题进行持续评估。 目前关注的焦点是气体的非热生物效应机制 身体激活（GBA）和惯性气穴，特别是与 涉及气体-体造影剂在诊断超声中的应用 程序. 如果最初存在合适的气体体，则发生GBA 有可能造成细胞膜损伤在更高的振幅下， 惯性空化可能会引发细胞DNA损伤的风险。 在哺乳动物中，这些现象可能是微妙的或具有戏剧性的破坏性： 潜在的有害副作用和治疗效果 效益 本研究有四个具体目标：（1）敏感非 计划采用旋转曝光系统， 细胞和气泡之间的相互作用，揭示了 剂量关系 (2)气体体造影剂注入 空化生物效应转化为其他无风险暴露的可能性 条件 实验的目的是描述 这些药物在低水平，并在确定他们是否可以导致 医学相关条件下的惯性空化。 此外，本发明还提供了一种方法， 将重点考察制剂的生物效应能力 用于治疗目的的特异性靶向癌细胞。 (3)DNA 细胞直接暴露于惯性空化诱导的链断裂 最近被新的“彗星”实验所揭示。 的机制 这种DNA损伤的遗传后果将被检查， 关系，如果有任何医疗超声将被确定。 （四） 肠道出血可以通过超声加热或 空化作用单独进行。 可能的协同增效作用， 将研究两种机制运作时的效果。 最后，组织 与气体造影剂的空化或激活相关的损伤 在其他器官，如肾脏，将进行调查和定义。 从这项研究中得到的定量剂量测定信息是 迫切需要对超声医师进行风险评估和指导， 开发医学超声的全部治疗潜力。

DESCRIPTION: (Adapted from investigator's abstract) The evolution of medical ultrasonics requires continual evaluation of safety issues. Concern presently centers on the nonthermal bioeffects mechanisms of gas body activation (GBA) and inertial cavitation, particularly in relation to the use of gas-body contrast agents in diagnostic ultrasound procedures. If suitable gas bodies are present initially, GBA occurs with a possibility of cell membrane damage. At higher amplitudes, inertial cavitation may be initiated with a risk of cellular DNA damage. In mammals, these phenomena can be subtle or dramatically destructive: the potential exists for both harmful side effects and therapeutic benefit. This research has four specific aims: (1) Sensitive non- rotating exposure systems are planned, which can bring out micro-scale interactions between cells and bubbles and reveal the fundamental dosimetric relationships. (2) Gas-body contrast agents inject the potential for cavitational bioeffects into otherwise risk-free exposure conditions. Experiments will be aimed at characterizing the behavior of these agents at low levels and at determining if they can lead to inertial cavitation under medically-relevant conditions. In addition, the bioeffects capability of the agents will be examined with emphasis on specific targeting of cancer cells for therapeutic purposes. (3) DNA strand breaks induced by direct exposure of cells to inertial cavitation have recently been revealed by the novel "comet" assay. The mechanisms and genetic consequences of such DNA damage will be examined, and its relation, if any to medical ultrasonics will be determined. (4) Intestinal hemorrhage can be induced by either ultrasonic heating or by cavitation acting alone. The possible synergistic enhancement of this effect will be studied when both mechanisms operate. Finally, tissue damage related to cavitation or activation of gas-body contrast agents in other organs, such as the kidney, will be investigated and defined. The quantitative dosimetric information resulting from this research is urgently needed for risk assessment and guidance of sonographers, and for developing the full therapeutic potential of medical ultrasound.