Introduction: Doppler mode ultrasound is widely used in prenatal scanning and known to produce a higher acoustic
output which later leads to higher heat energy conversion compared to other ultrasound modes. It has been reported
that the use of Doppler imaging might increase the temperature of tissues, thus, when Doppler is used in combination with 2D ultrasound, the risks of bioeffects tend to increase more. It is also known that prolonged exposure to
ultrasound during pregnancy can cause irreversible biological destructions to the fetus. Despite the benefits of using
Doppler ultrasound, its potential adverse effects have received scant attention in the research literature. Therefore,
this study aimed to examine a correlation between gestational stages (GS) and newborn rabbit’s body weight at different prenatal Doppler ultrasound exposure durations. Methods: Twelve pregnant New Zealand white rabbits (NZWR)
were exposed once using three different Doppler ultrasound exposure durations (30, 60, 90 minutes exposure) at
three different GSs (1st, 2nd, and 3rd GS). After delivery, the mean weights of the 62 newborns were statistically analysed. Results: Strong negative and positive correlation between newborn’s body weight at different GSs and Doppler
ultrasound exposure durations with a significant result found in 60 minutes exposure (p =
In medical imaging practice, the act of removing any clothes from the region of interest is justified as to prevent the presence of artefacts on radiographs. However, by doing so, the ‘aurah’ of the patients, especially for the Muslims, are not observed and can be considered as violating their privacy if they are not well-informed beforehand. Previous studies have proved that radiographs with the presence of some fabric materials on the region of interest are radiographically acceptable. Therefore, the aims of this study are to tackle the issue of exposing one’s ‘aurah’ for a knee x-ray examination to take place and also to add insufficiency from the previous studies.
Doppler ultrasound is used in obstetrics and gynecology fields to serve as the complement
mode in the standard prenatal scan. It aids in investigating fetus blood flow in expectant
mothers’ wombs, usually those who come with pregnancy complications. In the conventional
ultrasound beam, the heat produced by attenuation is distributed over the area. However, the
Doppler ultrasound beam is focused at only one point. This leads the heat to accumulate at
that particular area and hence there is an increase in the temperature. Heat is considered as
a teratogen in pregnancy, whereby an increase in the fetal temperature can be fatal to the
fetus. Studies have found that Doppler mode is associated with higher acoustic output as
compared to the conventional two-dimensional (2D) ultrasound mode. Several studies done
on animals have ruled out the evidence of Doppler ultrasound bioeffects. This narrative
review only discusses the thermally induced effect of ultrasound by using Doppler mode.
This study reviews prior studies with keywords such as Doppler ultrasound, bioeffects,
heating effects, rabbit, and pregnancy. Earlier studies noted that the risk of thermal effects
increased with the increase of exposure time. However, Doppler ultrasound wave inducing
fetal hyperthermia is not the main reason for
causing adverse neonatal outcomes without
taking into account other external factors.
Therefore, it is essential for the practitioners
to adopt and adapt the concept of ‘as low as
reasonably achievable’ (ALARA) to avoid
any subtle adverse effects.