Radionuclides in the management of thyroid cancer

Abstract

Nuclear medicine imaging was born over 60 years ago with imaging of thyroid conditions. Most of our present imaging devices were developed for imaging of the thyroid and thyroid cancer. Millions of patients in over 100 countries have been diagnosed and treated for thyroid cancer using nuclear medicine techniques. It remains, however, one of the most dynamic areas of development in nuclear medicine with new roles for positron emission tomography and receptor based imaging. In addition to this is research into combinations of genetic therapy and radioisotopes and receptor based therapy using beta emitting analogues of somatostatin. Despite the use of ultrasound computed tomography and magnetic resonance, nuclear medicine techniques remain central to both imaging and therapy in thyroid disease and the field has recently become one of the most dynamic within the specialty.

Figure 1

Large ‘cold nodule’ marked ‘c’ replacing and displacing the lower pole of the left lobe of the thyroid in a 55-year-old woman. Subsequent ultrasound and fine needle aspiration confirmed a simple colloid cyst.

Figure 2

Anterior and posterior whole body images performed 48 h after administration of 5 GBq of ¹³¹I therapy. Note some stomach and colonic activity is seen but all other sites are metastatic papillary thyroid cancer.

Figure 3

Two approaches to ablation and treatment of thyroid remnant and metastases.

Figure 4

Fused [¹⁸F]FDG PET-CT images in a patient with renal cancer showing two areas of uptake of tracer in the right and left lobes of the thyroid; subsequent investigation showed these to be nodules in a multi-nodular goitre.

Figure 5

Whole body [¹¹¹In]pentetreotide imaging showing a large metastasis in the upper inner right lung not seen on ¹³¹I imaging but demonstrating somatostatin receptor positivity.

Figure 6

Coronal SPECT [¹¹¹In]pentetreotide image showing extensive somatostatin positive uptake in lymph nodes invaded by medullary cell cancer of the thyroid (the red areas are the cancer). These were treated by surgery and radiotherapy.

Figure 7

Images performed 24 h after administration of [⁹⁰Y]octreotate therapy in a patient with metastatic medullary cell cancer of the thyroid. Liver, kidney and splenic uptake in normal other sites represent metastatic disease. Note abnormal uptake in skull, shoulder, sternum and pelvis. This patient had a good response to this therapy sustained over 12 months later.