The invention relates to a compound of formula : wherein P1, P2, P3, and P4 are each independently hydrogen or a protecting group; and n is an integer of from 2 to 20 and to the use of such compounds for the synthesis of 18F-FDG. The carbon black has a residue on sieve of from 0. The front segment pre-charges while the rear segment evaluates, and vice versa. The intensity of illumination of the luminescent sheet may be controlled by the user and may vary in response to the background light of the environment.