Image registration of SPECT and CT images using an external fiduciary band and three-dimensional surface fitting in metastatic thyroid cancer

Image registration of ¹³¹I SPECT with CT scans was performed in a patient with metastatic thyroid carcinoma using an external fiduciary band and a three-dimensional surface-fitting algorithm. Areas of metastatic disease taking up ¹³¹I were accurately localized to the liver, lungs and vertebral bodies; providing information that could not be obtained by planar or SPECT images alone. Based on these findings, further invasive diagnostic procedures were not performed, therefore considerably altering management in this patient. This approach to image registration has immediate clinical utility in the registration and interpretation of SPECT studies with corresponding CT or MRI scans.