The use of SPECT-CT in determining 90Y microspheres distribution post selective internal radiation therapy

Hepatocellular carcinoma and metastatic colorectal carcinoma are amongst the more common causes of cancer-related mortality worldwide. Selective internal radiation therapy (SIRT) with 90y microspheres is usually indicated in patients with nonresectable status and extensive colorectal liver metastases that are refractory to chemotherapy or target therapy. Several examinations, including CT, MRI or PET, serum chemical analyses, hepatic angiography and liver-lung shunting study with Tc-99m MAA, are done to ensure appropriateness and safety of therapy. Herein, three cases (two with hepatocellular carcinoma and one with metastatic colorectal cancer), which qualified for SIRT and underwent SPECT-CT, are presented. All of them underwent the necessary pre-therapy work-ups. The CT and PET-CT scans identified the hepatic lesions. The blood tests showed nearly normal hepatic and renal functions, except for the third case with elevated bilirubin level. The hepatic angiograms revealed no significant gastrointestinal shunting. The liver-lung shunting studies computed 10% hepatopulmonary shunt. Together with the patient with an elevated bilirubin level, they received a reduced dose of 90Y microspheres by 20%. After SIRT, bremsstrahlung planar imaging and SPECT-CT were performed to localize the distribution of the 90y microspheres, the findings of which correlated well with the results of the pre-therapy scans. The use of SPECT-CT is recommended for better anatomic localization and functional correlation.

I131 MIBG imaging in the diagnosis of pheochromocytoma: Philippine setting

The clinical diagnosis of pheochromocytoma is easy, considering that it manifests as labile hypertension, attacks of palpitations, headache, sweating, pallor or flushing. Urinary VMA or metanephrines seem to be the first investigative step as well as a CT scan to localize it as 85-90 percent arise from the adrenal medulla. Ten percent of these tumors are bilateral but non-adrenal tumors may arise from the sympathetic ganglia, usually alongside the aorta or its branches and in the wall of the urinary bladder. One percent is found outside the abdominal cavity. Meta-iodobenzyl guanidine (MIBG) is an excellent scanning agent that is taken up by most benign and malignant pheochromocytoma tissues. While this procedure is quite costly and underutilized in the Philippines, this paper was done to review its indications and how helpful it can be. From 2001 -2005, I131 MIBG scintigraphy was done only in 17 patients in two medical centers to confirm the diagnosis of pheochromocytoma. The clinicians must be informed that this is not a screening procedure but it is particularly helpful in surveying the entire body for adrenal and extra-adrenal metastatic lesions. It is also diagnostic of intra-adrenal paragangliomas, neuroblastoma, carcinoids, and medullary thyroid carcinoma. This study was, likewise, done with the thought that MIBG may be utilized in the future for therapy as it has shown to be effective in pheochromocytoma and neuroblastoma.