Hi. Breast development and the emergence of other secondary sex characteristics (pubic and armpit hair, appearance of “curves” in women) depend on the increase in sex hormone production (estrogen) at the time of puberty. Estrogen production, in turn, is dependent on the following factors: 1) hormonal stimuli provided by the hypothalamus and pituitary gland (organs located beneath the brain), and 2) an intact ovary with viable egg cells.
Any treatment which can damage both the hypothalamus/pituitary gland and the ovaries can decrease estrogen production and delay pubertal development. Unfortunately, total body irradiation can cause this kind of damage. In a study done by Ogilvy-Stuart, et al (1992), the endocrine function of 31 children was studied after total body irradiation. Fifteen children showed damage to their gonads, and all of the girls (5 in number) who were at the age of puberty at the time of treatment had ovarian failure (non-functioning ovaries). One of these girls was eventually found to have recovery of ovarian function.
So what can you expect? There is a chance that the radiation could cause enough damage to your endocrine organs and arrest pubertal development. If the damage is not as extensive, the appearance of your secondary sex characteristics may be delayed. I think what can be done is to determine the extent of damage and the current functional status of your ovaries and pituitary/hypothalamus. An endocrinologist or a gynecologist may be able to help you with this matter.
[weblink to Ogilvy-Stuart’s study: http://www.ncbi.nlm.nih.gov/pubmed/1417055?ordinalpos=16&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_RVDocSum]