Percentage of thyroid nodules with microcalcification who had radiation as child that is malignant?

More risk: Any thyroid nodule is of concern in patients with a history of cervical irradiation. Those with fine calcification can represent papillary cancer. Percentages don't matter as much as needle biopsy proof that the nodule is benign.

High enough: High enough that you should definitely have a thyroid biopsy and be considered for possible surgery. What difference does the exact percentage make?

Biopsy: Thyroid nodules with microcalcifications are considered suspicious and therefore fine needle aspirations should be considered for definitive diagnosis. If fna fails to make the diagnosis, surgical excision may be considered.