Nuclear Medicine

TREATMENT OF LIVER CANCER WITH MICRO-SPHERE METHOD
Liver cancer is a prevalent type of cancer not only in our country but also in U.S. and European countries. Successful outcomes are obtained in management of liver cancer with microsphere – a new generation therapy – along with chemotherapy and medication therapies. It took attention of medicine community due to almost total absence of side effect and other advantageous features.What are characteristics of liver cancer?Liver cancers are addressed in 2 main groups. First group involves primary cancers that imply cancerous formations originating from hepatic cells, while second group is metastatic tumors that metastasize from cancers of other organs. Primary liver cancers also imply hepatocellular cancers that originate from native cells of liver.What is difference of micro-sphere methods in comparison to other methods?Micro-sphere method is a specific therapy. Chemotherapy and medications are systemic therapy methods. In other words, they do not absolutely target the lesion in liver. “Specific therapy” implies that there will be no systemic side effect, or in other words, patient will not encounter exhaustive side effects that occur after chemotherapy.What is incidence of liver cancer?Five hundred thousand to 1 million new primary cancer cases are diagnosed per annum worldwide.  When metastatic cases are considered, pancreas and colon cancers are most common ones.Hepatic metastases account for 50 to 70 of pancreas and colon cancers. This is an extremely high rate. Another striking figure is about the fact that 20% of deaths due to colon cancers arises out of hepatic metastases. In this respect, both primary cancers and metastatic cancers are of remarkable clinical significance.How is treatment applied?Micros-sphere method is based on principle of using micro-spheres that measure 20 to 50 microns in size and are labeled with Yttrium-90 – a radioactive material that emits beta particles. Micro-spheres labeled with Yytrium-90 are directly injected to arteries that supply blood directly to liver. Thus, preparation accumulates only on tumor tissues located in the liver.Since they accumulate in tumor tissues and occlude capillaries that feed tumor tissues, it is also referred as “radio-embolization method”. Femoral artery is punctured and a catheter is inserted (similar to coronary angiography), and thus, drug is directly administered into feeding artery of liver. 

What are treatment methods?
There are various treatment methods for liver cancers. The first one is surgical treatment, although not all patients are eligible for surgery. This indication is related with tumor content of liver. If tumor load is very high in liver or if there is more than one lesion, surgical treatment is contraindicated. Chemotherapy and specific drugs are therapeutic options for group of inoperable patients. However, primary cancers of liver are particularly resistant to therapy.Since metastatic lesions are usually multiple in nature, strong response to therapy methods mentioned above cannot be obtained. Therefore, radioembolization method is used that is recently introduced to clinical use. In radioembolization method, microspheres (20 to 50 microns in size) labeled with radioactive material are directly delivered to feeding artery of liver and thus, therapy is applied.What are advantages and disadvantages of the method?Being a local therapy and absence of exhaustive side effects that are observed in chemotherapy are most significant advantages of micro-sphere method. The second advantage is that this therapy method can be easily applied to patients who already received chemotherapy, chemoembolization therapy or surgical treatment. Briefly, micro-sphere method can be combined with other treatments. If therapy helps findings of cancer, the procedure can be repeated, if required.Which patients are eligible for micro-sphere method?Since this method primarily targets liver cancers, they are applied to both metastatic or hepatocellular cancers. However, this therapy is not a therapeutic option in this combined group of patient, if tumor load is high, or in other words, liver is largely infiltrated. If patient has a condition of liver failure, it will be useless again. Preliminary tests are analyzed to determine patients who are eligible for this method.How many patient received this therapy and what is success rate?To date, many patients received this therapy worldwide. This procedure has been widely used in Turkey approximately for 4 to 5 years. This specific method is applied in several healthcare facilities in our country. Approximately 200 patients received this therapy per annum.  This implies that minimum 1000 patients are treated, to date, with this method in Turkey, but it has been very widely used in U.S. and European countries for 10 to 15 years.Neuro-endocrine tumors are rich in somatostatin receptors (SSTr).Group of tumors rich in SSTrGastroenteropancreatic tumors (carcinoid, gastrinoma, insulinoma, glucagonoma, VIPoma)Sympatho-adrenal system tumors (pheochromocytoma, paraganglioma, neuroblastoma, ganglioneuroma)Medullar thyroid carcinoma Pituitary adenoma Merkel cell carcinoma Small cell lung cancerBreast carcinoma MelanomaLymphomaProstate cancerNon-small cell lung cancer SarcomaRenal cell carcinoma Differentiated thyroid carcinomaAstrocytomaMeningioma.GA68 DOTA PEPTIDE PET/CT SCAN IN NEUROENDOCRINE TUMORS (SOMATOSTATIN RECEPTOR IMAGING)Conventional imaging methods are characterized with very limited performance and low sensitivity in staging, re-staging and evaluating therapy response in neuroendocrine tumors. Since glucose metabolism is slow in neuroendocrine tumors, sensitivity of FDG PET/CT scan is low. Since SSTr is imaged with GA 68 DOTA Peptide PET/CT scan, molecular SSTr content of neuroendocrine tumor is demonstrated in high sensitivity with this method.INDICATIONS OF GA 68 DOTA PEPTIDE PET/CTInvestigating localization and metastatic focus of primary tumor (staging)
Determining presence of residue, recurrence or progression (re-staging)Determining indication of Lu-177 therapy in case of metastatic disease according to Ga68 peptide uptake.Response to therapy (surgery, radiotherapy, chemotherapy or Lu-177 Peptide therapy)Special precautions taken before or after imaging. This examination is absolutely contraindicated only for pregnant women. GA 68 DOTA Peptide PET/CT imaging is similar to FDG PET/CT scan in terms of imaging technique.  The only difference is radiopharmaceutical agent used.
Lutetium (Lu-177) PEPTIDE THERAPY IN NEURO-ENDOCRINE TUMORSSince Lu177 is a radionuclide that emits beta particles, it penetrates into tissue by 1 to 3 mm. Based on this characteristic, it enables specific and internal radiotherapy approach. Positive lesions on Ga 68 DOTA Peptide PET/CT will point out uptake of Lu177-labelled peptide.Lu-177 peptide is indicated for management of all inoperable and/or metastatic neuroendocrine tumors that show positive SSTr content on Ca 68 DOTA Peptide PET/CT scan.Administration: Lu177-labelled peptide is diluted with isotonic sodium chloride (10-100 ml) and intravenously infused at 10 to 20 minutes. Patient should stay, minimum for one day, in a single room that is specifically licensed by Turkish Atomic Energy Authority regarding radiation safety. Therapy cycle periods: Lu therapy is usually given in 4 to 5 cycles at 6- to 8-week intervals.

What are side effects?
Acute side effects: Nausea, vomiting, abdominal pain. Nephrotoxicity: Nephrotoxicity is minimized, to the possible extent, with renoprotective therapies. Bone marrow toxicity: It is a reversible condition that develops in 2-5% of patients especially if patients have diffuse bone metastasis. Efficiency of TreatmentLu177 have been used worldwide in management of neuroendocrine tumors approximately for one decade. This therapy has been available in particular healthcare facilities in our country approximately for 3 years. Literature data demonstrated that Lu-177 peptide prolongs survival, improves symptoms, restores biochemical markers into normal range and contributes to enhancement of quality of life in patients with SSTr-positive neuroendocrine tumor.

GALLIUM (68Ga)-LABELED PSMA PET IN PROSTATE CANCER
Prostate cancer is the second most common type of cancer in male subjects and sixth most common disease among all causes of death. Similar to all other cancer, it is very important to determine best therapy method timely in prostate cancers.Recently, total body is scanned and metastatic status of prostate cancer can be determined with Gallium (68Ga)-labeled PSMA PET scan. PSMA is a substance that is totally specific to prostate gland. When this substance is used in Galium (68Ga) PET scan, uptake is observed only in regions which are involved by prostate cancer.Current status of disease is revealed out with Galium(68Ga)-labeled PSMA PET scan and thus, best therapy method is selected.