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A vaginal plethysmograph system utilizing an indirectly (reflected) lighted photocell probe has been developed and used experimentally with excellent results. While the standard lamp and photocell plethysmograph using transmitted light is not unique, its application in measuring vaginal blood volume presented numerous instrumentation and mechanical problems not previously encountered. It is believed that this is the first system to reliably measure vaginal blood volume changes by indirect methods.
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Sintchak et al. (1975) studied this question.
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