scholarly journals Safety of Transvaginal Scan Estimated from Ultrasonic Bioeffects

2017 ◽  
Vol 11 (1) ◽  
pp. 1-6
Author(s):  
Kazuo Maeda
Keyword(s):  
Cell Growth ◽  
Negative Pressure ◽  
Fetal Tissue ◽  
Biological Tissues ◽  
Diagnostic Ultrasound ◽  
Ultrasound Wave ◽  
Mechanical Index ◽  
Output Intensity ◽  
Thermal Status ◽  
Excess Heating

ABSTRACT The embryo and fetus are generally studied using ultrasound imaging in pregnancy; however, ultrasound wave is absorbed by biological tissues to elevate the temperature. The growing embryonic and fetal tissue tends to be damaged by heating; thus, excess heating that damages young sensitive growing tissue should be prevented in ultrasound diagnosis. Hence, the thermal status of diagnostic ultrasound should be known with thermal index (TI), of which the determination and application are discussed in this chapter. Peculiar problem to transvaginal scan and thermal problem in febrile patient are discussed. Additionally, the cavitation, which is related with negative pressure, develops high pressure, high temperature, and free radicals that damage embryonic and fetal tissues. Therefore, the mechanical index (MI) has to be determined, measuring negative pressure of ultrasound. The MI is determined for the safety of diagnostic ultrasound. The ultrasound device output intensity that suppresses fetal amniotic JTC-3 cultured cell growth was determined, where 240 mW/cm2 or less output intensity did not suppress the cell growth, namely, the diagnostic ultrasound has no bioeffect when the output is lower than 240 mW/cm3. The as low as reasonably achievable principle in the Doppler method of 0.1 TI will be discussed. Three experimental reports of hazardous effects of ultrasound are discussed. How to cite this article Maeda K. Safety of Transvaginal Scan Estimated from Ultrasonic Bioeffects. Donald School J Ultrasound Obstet Gynecol 2017;11(1):1-6.

scholarly journals Diagnostic Ultrasound Safety

2014 ◽  
Vol 8 (2) ◽  
pp. 178-183 ◽  
Author(s):  
Kazuo Maeda
Keyword(s):  
Obstet Gynecol ◽  
Physical Property ◽  
Diagnostic Ultrasound ◽  
Mechanical Effect ◽  
Mechanical Index ◽  
Pulsed Doppler ◽  
Output Intensity ◽  
Thermal Index ◽  
4D Ultrasound ◽  
Pulsed Doppler Ultrasound

ABSTRACT Ultrasound bioeffect is discussed from its physical property, i.e. thermal effect by thermal index, mechanical effect by mechanical index, and by the output intensity of ultrasound. Generally, thermal and mechanical indices should be lower than 1 in obstetrical setting, and threshold output intensity of no bioeffect is lower than SPTA 240 mW/cm2 in pulse wave. Pulsed Doppler ultrasound thermal and mechanical indices should be also lower than 1, and should be carefully used it in 11 to 13+6 weeks of pregnancy. Real-time B-mode, transvaginal scan, pulsed Doppler, 3D and 4D ultrasound were separately discussed in the ultrasound safety. Generally diagnostic ultrasound is safe for the fetus and embryo, if thermal and mechanical indices are lower than 1, and ultrasound devices are safe, if it is used under official limitation, e.g. the output intensity is less than SPTA 10 mW/cm2 in Japan. The ultrasound user is responsible ultrasound safety, e.g. higher thermal and mechanical indices than 1 should be lowered to be lower than 1, controlling the device output intensity. The user should learn bioeffects of ultrasound and prudent use of ultrasound under the ALARA principle. How to cite this article Maeda K, Kurjak A. Diagnostic Ultrasound Safety. Donald School J Ultrasound Obstet Gynecol 2014;8(2):178-183.

scholarly journals Combination of microbubbles and diagnostic ultrasound at a high mechanical index for the synergistic microwave ablation of tumours

2016 ◽  
Vol 33 (3) ◽  
pp. 318-326 ◽  
Author(s):  
Jinshun Xu ◽  
Yang Cao ◽  
Chunyan Xu ◽  
Xueqing Cheng ◽  
Yufeng You ◽  
...  
Keyword(s):  
Microwave Ablation ◽  
Diagnostic Ultrasound ◽  
Mechanical Index

scholarly journals Diagnostic Ultrasound High Mechanical Index Impulses Restore Microvascular Flow in Peripheral Arterial Thromboembolism

2016 ◽  
Vol 42 (7) ◽  
pp. 1531-1540 ◽  
Author(s):  
Thomas R. Porter ◽  
Stanley Radio ◽  
John Lof ◽  
Carr Everbach ◽  
Jeffry E. Powers ◽  
...  
Keyword(s):  
Diagnostic Ultrasound ◽  
Mechanical Index ◽  
Arterial Thromboembolism ◽  
Microvascular Flow ◽  
Peripheral Arterial

Nonlinear effects of the finite amplitude ultrasound wave in biological tissues

2000 ◽  
Vol 45 (6) ◽  
pp. 508-512 ◽  
Author(s):  
Xiaozhou Liu ◽  
Xiufen Gong ◽  
Shigong Ye ◽  
Weiya Zhang
Keyword(s):  
Nonlinear Effects ◽  
Biological Tissues ◽  
Finite Amplitude ◽  
Ultrasound Wave

Therapeutic effect of diagnostic ultrasound on enzymatic thrombolysis

2004 ◽  
Vol 91 (06) ◽  
pp. 1078-1083 ◽  
Author(s):  
Cristiana Lupi ◽  
Guido Lazzerini ◽  
Piero Chiarelli ◽  
Antonio L’Abbate ◽  
Daniele Rovai ◽  
...  
Keyword(s):  
Venous Blood ◽  
Normal Subjects ◽  
Vascular Wall ◽  
Diagnostic Ultrasound ◽  
In Vitro Models ◽  
Mechanical Index ◽  
Ultrasound Exposure ◽  
Tissue Plasminogen ◽  
Artery Disease

SummaryIf delivered at elevated intensity, ultrasound potentiates enzymatic clot dissolution; however, an elevated acoustic intensity damages vascular wall and favors reocclusion. This study’s aim was to investigate whether exposure to high-frequency, lowintensity ultrasound generated by a diagnostic scanner enhances enzymatic thrombolysis, and if this effect differs in clots from blood of normal subjects and of patients with coronary artery disease (CAD). Venous blood samples were drawn from 10 healthy volunteers and from 10 CAD patients on chronic medical treatment, which also included aspirin. Each sample generated 2 radiolabelled clots, which were positioned in 2 in vitro models filled with human plasma recirculating at 37°. One clot was exposed to acetyl salicylic acid (60 μg/ml), tissue plasminogen activator (3 μg/ml) and heparin (1 IU/ml), while the other was exposed to the same medications plus ultrasound (2.5 MHz, mechanical index = 1.0) for 3 hours. Enzymatic thrombolysis was measured as solubilization of radiolabel. Normal subjects and patients did not significantly differ as to coagulation parameters, weight, volume and density of the clots, and fibrinolytic activity (p = 0.794). Ultrasound exposure did not influence thrombolysis in clots of normal subjects (p = 0.367), while it enhanced the dissolution of clots of CAD patients (p = 0.013). The enhancement was equal to 51% at 5 minutes, 32% at 15 minutes, 27% at 30 minutes, 20% at 1 hour and 19% at 3 hours (p < 0.05). Diagnostic ultrasound enhances enzymatic dissolution of clots generated from the blood of CAD patients, likely due to chronic treatment and in particular to aspirin.

scholarly journals Quantitative ultrasound imaging of soft biological tissues: a primer for radiologists and medical physicists

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Guy Cloutier ◽  
François Destrempes ◽  
François Yu ◽  
An Tang
Keyword(s):  
Quantitative Ultrasound ◽  
Tissue Characterization ◽  
Liver Steatosis ◽  
Ultrasound Image ◽  
Biological Tissues ◽  
Quantitative Information ◽  
Ultrasound Wave ◽  
Ultrasound Waves ◽  
Medical Physicists ◽  
General Topic

AbstractQuantitative ultrasound (QUS) aims at quantifying interactions between ultrasound and biological tissues. QUS techniques extract fundamental physical properties of tissues based on interactions between ultrasound waves and tissue microstructure. These techniques provide quantitative information on sub-resolution properties that are not visible on grayscale (B-mode) imaging. Quantitative data may be represented either as a global measurement or as parametric maps overlaid on B-mode images. Recently, major ultrasound manufacturers have released speed of sound, attenuation, and backscatter packages for tissue characterization and imaging. Established and emerging clinical applications are currently limited and include liver fibrosis staging, liver steatosis grading, and breast cancer characterization. On the other hand, most biological tissues have been studied using experimental QUS methods, and quantitative datasets are available in the literature. This educational review addresses the general topic of biological soft tissue characterization using QUS, with a focus on disseminating technical concepts for clinicians and specialized QUS materials for medical physicists. Advanced but simplified technical descriptions are also provided in separate subsections identified as such. To understand QUS methods, this article reviews types of ultrasound waves, basic concepts of ultrasound wave propagation, ultrasound image formation, point spread function, constructive and destructive wave interferences, radiofrequency data processing, and a summary of different imaging modes. For each major QUS technique, topics include: concept, illustrations, clinical examples, pitfalls, and future directions.

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