Radio Button Help with session variables

I have some code below that outputs a Radio button list. This will create about 6 different Radio points. However im stuck on how i can create a session varible for each Radio button, so everytime a user clicks on the Radio button (or on the 'submit' button) this will create a session varible with the value = $test. Session_start() has been added before this code
.............
//This will output a Radio button list
echo "<form action='Cleanser_step3.php' name='form2' method='POST'>";
for ($test=1; $test<=$column1; $test++){
echo "<label>";
echo "<input type='radio' name='Col$test' value=$test" ;
if (isset($fields['Col$test']) == '$test') echo 'checked';
echo ">";
echo "Column ".$test;
echo "</label>";
echo "<br>";
}
echo "<input type='submit' align='right' value='Next >>'>";
$_SESSION['$DimOther'] = $DimOther;
echo "</form>";
}
................

 

try using col[$test] instead of col$test, then you make an array... but note, that all the options have unique names so if you click one, the other will NOT unmark.