Possible effects of grenz-ray therapy are qualitatively identical to those of conventional x-rays.
The principal adverse effects are erythema and pigmentation. Grenz-ray erythema is relatively asymptomatic, and its latent period is shorter than that of conventional x-ray erythema.
It is ordinarily not followed by sequelae other than pigmentation.(2) The intensity of this cutaneovascular reaction varies greatly, not only among different individuals but also among different body regions of the same individual.
(7) Pigmentation may result from grenz-ray therapy and close shielding should be avoided in order not to produce a sharp line at the edge of the treated area. Pigmentation so induced varies with race, age, and body region, but is never permanent.
(8) Large doses may occasionally give rise to a peculiar pigment displacement, a spotty hyperpigmentation instead of uniform hyperpigmentation.(2)