Often, ultrasound technology and computer tomography can be helpful in conducting certain procedures to check and treat growths, lesions or abnormalities in body tissues. Doctors may perform CT or ultrasound guided aspiration wherein a thin, hollow needle is inserted into the growth/lesion and fluid is drained, while being guided by the images on the computer. In a biopsy, a similar procedure is carried out to remove a small piece of the affected tissue to rule out any malignancy.