Here's one way of doing it. I can't help but think that Template would make this so much easier. In your case, you may just want to use HTML::FillInForm. Check it out :)

use strict;
use CGI::Simple qw(-debug2);
use HTML::Template;

my $q = CGI::Simple->new();
my $t = HTML::Template->new( filehandle => \*DATA );

my $type = $q->param('type') || 1;

$t->param(
    type_values => [
        map { {
            value   => $_,
            checked => ($_ eq $type ? 'CHECKED' : '')
        } } 1..12
    ]
);

print $q->header(), $t->output();

__DATA__
<TMPL_LOOP NAME="type_values">
    <input type="radio" name="type"
        value="<TMPL_VAR NAME="value">"
        <TMPL_VAR NAME="checked"> />
</TMPL_LOOP>
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