Standard Procedure for Thyroid Cancer Assessment Thyroid nodules have a very high incidence worldwide, but on average, approximately only 5% of them is malignant. The diagnostic procedure for the assessment of their nature is an ultrasound examination followed by fine needle aspiration biopsy (FNA). However, FNA is invasive, painful, complications may occur and usually only 9-13% of analysed nodules result in being malignant. These reasons show the need to reduce the number of unnecessary biopsies and increment the efficiency of feature extraction from US images. Study of Vascularization As pointed out in different studies, vascular pattern could be useful not only in avoiding FNA when not necessary, but also in the characterization of nodules with undetermined fine-needle aspiration biopsy results (THY 3a, THY 3b).