PURPOSE: The aim of this experimental study was to evaluate whether the acoustic radiation force (ARF) is a potential source of twinkling artifacts in color Doppler images. METHODS: Color Doppler images were obtained using a clinical ultrasonic scanner (Voluson e, GE Healthcare) for a high contrast (+15 dB) circular scattering phantom at pulse repetition frequencies (PRFs) ranging from 0.1 to 13 kHz. Ultrasound transmissions resulting in ARF were measured using a hydrophone at the various PRFs considered. The influence of ARF on the appearance of twinkling colors was examined via the common parameter PRF. This methodology is based on the fact that alternating positive and negative Doppler shifts induced by the ARF are centered at a PRF twice the maximum Doppler frequency on the color scale bar, whereas the twinkling color aliasing is expected to remain similar regardless of PRF. RESULTS: Color twinkling artifacts were observed to be most conspicuous at the lowest PRF of 0.1 kHz. The extent of twinkling rapidly decreased as the PRF increased, eventually disappearing when the PRF > or =0.6 kHz. The measured ultrasound transmissions, however, were found to be insensitive to the PRF, and therefore it can be inferred that the PRF was insensitive to the ARF. CONCLUSION: Based on our experimental observations, the ARF may not be a source of color Doppler twinkling artifacts.
Acoustics* ; Artifacts* ; Doppler Effect ; Ultrasonics ; Ultrasonography ; Ultrasonography, Doppler, Color

Excellent research in the fields of medicine and medical science can advance the field and contribute to human health improvement. In this aspect, research is important. However, if researchers do not publish their research, their efforts cannot benefit anyone. To make a difference, researchers must disseminate their results and communicate their opinions. One way to do this is by publishing their research. Therefore, academic writing is an essential skill for researchers. However, preparing a manuscript is not an easy task, and it is difficult to write well. Following a structure may be helpful for researchers. For example, the standard structure of medical and medical science articles includes the following sections: introduction, methods, results, and discussion (IMRAD). The purpose of this review is to present an introduction for researchers, especially novices, on how to write an original article in the field of medicine and medical science. Therefore, we discuss how to prepare and write a research manuscript for publication, using the IMRAD structure. We also included specific tips for writing manuscripts in medicine and medical science.

This study was to optically visualize the cavitation bubbles produced by a clinical shock wave and to look into their geometric features of the resulting cavitation bubbles in relation to the driving shock wave field. A clinical shock wave therapeutic system was taken for shock wave production. The shock wave induced cavitation bubbles were captured by a professional camera under the illumination of a micro-pulse LED light. The light exposure was set to last for the whole life time of bubbles from formation to subsequent collapses. It was shown that the cavitation bubbles appeared mostly in the vicinity of the focus. The bubbles became more and larger as approaching to the focus. The cavitation bubbles formed jet streams which became enlarged (stronger) as the shock wave device output setting increased. The bubble cloud boundary was reasonably fitted to an elongated ellipsoid characteristically similar to the acoustic focal area. The bubble clouds were enlarged as the output setting increased. The geometric features of the cavitation bubbles characteristically similar to those of the focusing acoustic field have potential to provide the therapeutic focal information without time consuming hydrophone measurements of the shock wave field causing damages of the expensive sensor. The present study is limited to the static afterimages of the cavitation bubbles and investigation including the bubble dynamics is suggested to deliver the more realistic therapeutic area of the shock wave therapy.
Acoustics ; Afterimage ; Lighting ; Rivers ; Shock*