Hi Gsunshine
The culprit in hairloss is usually taxotere (or any "taxol" sounding drug) for those undergoing chemotherapy as part of their treatment (ie multiple agents used together in a "cocktail").
In your case, cisplatin used in conjunction with radiation helps make the radiation work better and whilst it is a cytotoxic agent and is certainly used in "cocktails" as chemotherapy, it's use during radiation is not strictly "chemotherapy" so much as "chemoboosting".
There is some hair loss associated with radiation as already stated but only where the radiation hits. Cisplatin is not generally associated with hair loss.
There is always the exception to the rule but I wouldn't be racing out to buy any beanies or wigs right now