why don't we freeze 35-S Autorads ?

[mac-biocomputing1user]

Hi ...this week I followed the "cool" discussion about why do we freeze
autorads and while I was reading all the answers I was wondering why
don't we freeze autorads when we expose dried polyacrilammide gel for
sequencing where the isotope used is usually 35-S instead of 32-P !!!???

1) It depends on the physical-chemical properties of the gel that might 
crash at highest low temperature ......?

2) It is a metter of the particular isotope (35-S or 32-P) and so of the
different decay and particles emitted

I would appreciate any suggestion....thanks !

Davide
corona at EMBL-Heidelberg.DE