A catalyst and process for hydrotreating and/or hydroconverting heavy metal-containing hydrocarbon feeds, said catalyst comprising a support in the form of beads based on alumina, at least one catalytic metal or a compound of a catalytic metal from group VIB (column 6 in the new periodic table notation), optionally at least one catalytic metal or compound of a catalytic metal from group VIII (columns 8, 9 and 10 of the new periodic table notation), with a pore structure composed of a plurality of juxtaposed agglomerates, each formed by a plurality of acicular platelets, the platelets of each agglomerate being generally radially orientated with respect to each other and with respect to the center of the agglomerate. The catalyst also comprises at least one doping element selected from the group constituted by phosphorus, boron, silicon (or silica which does not belong to that which could be contained in the selected support) and halogens.