Figure 22. 123I-mIBG scan in a five year old child with extensive skeletal metastatic involvement with neuroblastoma. There is diffuse abnormal activity throughout the skeleton resulting in an 123I-mIBG scan which looks like a bone scan.

possible technical difficulties such as prior neck surgery; (iii) patients in whom surgery is high risk; or (iv) equivocal ultrasound or CT (sensitivities of 50-75%).

Although thallium imaging with 99mTc-pertechnetate thyroid subtraction was performed in the past, most centers now use 99mTc-sestamibi, either with 99mTc-pertechnetate or alone. 99mTc-sestamibi has high sensitivity and specificity (85-95%),

3I-mIBG scan in a patient with a left adrenal

Figure 23. Anterior and posterior 1 pheochromocytoma (arrowheads).

3I-mIBG scan in a patient with a left adrenal is technically easy to perform, and has become the investigation of choice. Images are obtained immediately after 99mTc-sestamibi injection and at about 2-3 hours by which time washout from normal thyroid tissue will have occurred and activity will be retained in the parathyroid adenoma (Fig. 25). 99mTc-pertechnetate or 123I imaging may be useful in defining the functional anatomy of the thyroid gland for comparison with 99mTc-sestamibi abnormalities.

Prostate cancer

The most frequent nuclear medicine examination performed in patients with prostate cancer is the bone scan which is discussed elsewhere in this handbook. More recently, there has been interest in the use of a radiolabelled monoclonal antibody, capromab pendetide (Prostascint®), in evaluating patients with: (i) a new diagnosis of prostate cancer, (ii) those with a high risk of recurrence, or (iii) a rising PSA with negative bone scan and CT. Several groups have reported a management benefit when antibody imaging is used as an adjunct to CT, particularly in the first 2 indications. There is a steep learning curve to the interpretation of these images,

0 0

Post a comment