The thermal dose index.
OBJECTIVE
A new index is proposed to help sonographers easily assess the risk of an adverse thermal effect arising from a clinical examination. It is called the thermal dose index (TDI).


METHODS
The TDI uses the familiar thermal index (TI) and the examination duration to compute a dimensionless index.


RESULTS
The greater the TDI value, the greater the risk of a thermally induced adverse effect. If the TDI is 1 or less, there is no expectation of a thermally induced adverse effect.


CONCLUSIONS
Like the TI, the TDI would be a convenient index that is continually updated and displayed during an ultrasound examination. The TDI is a new estimate of thermal risk that takes into account the duration of an ultrasound examination.
Ziskin
Marvin C
MC
Center for Biomedical Physics, Temple University School of Medicine, Philadelphia, PA 19140, USA. ziskin@temple.edu
D001831:Body Temperature / Q000502:physiology*; D006801:Humans; D018570:Risk Assessment / Q000379:methods; D013223:Statistics as Topic; D014463:Ultrasonography / Q000009:adverse effects*; D016216:Ultrasonography, Prenatal