Radiation and Thyroid Hormone
I completed 15 sessions of radiation therapy to my chest wall, axilla and supra-clavicular area on 19th November. Last week I did a thyroid panel blood test which shows that despite not altering my thyroid medication, my Free Thyroxine levels have dropped to way below the bottom of the reference range. It used to be in the top third of the reference range. It's never been this low before.
My Free T3 had also dropped but was still within the reference range. (I take thyroid meds that contain both T3 and T4, which is likely why my body used up the T4 but still had some T3 left in the blood)
Can radiotherapy affect either the thyroid gland itself, or the body's need for thyroid hormones?