My final code is:
FORM f_verifica_periodo USING num_bloco TYPE c
nome_campo TYPE fieldname.
DATA: codlocal TYPE string,
codaneel TYPE string,
l_char TYPE c LENGTH 72.
CONCATENATE: 'S_CODLO' num_bloco INTO codlocal,
'S_ANEEL' num_bloco INTO codaneel,
nome_campo num_bloco INTO nome_campo.
FIELD-SYMBOLS: <fs_range> TYPE ANY TABLE,
<fs_line> TYPE any,
<fs_comp_low> TYPE any,
<fs_comp_high> TYPE any.
CONCATENATE '(' sy-repid ')' nome_campo '[]'
INTO l_char.
ASSIGN (l_char) TO <fs_range>.
LOOP AT <fs_range> ASSIGNING <fs_line>.
" Recupera valor dinamicamente do campo LOW - Coluna 3
ASSIGN COMPONENT 3 OF STRUCTURE <fs_line> TO <fs_comp_low>.
CHECK sy-subrc EQ 0.
" Recupera valor dinamicamente do campo HIGH - Coluna 4
ASSIGN COMPONENT 4 OF STRUCTURE <fs_line> TO <fs_comp_high>.
CHECK sy-subrc EQ 0.