An overview of the role of Nuclear Medicine in Pulmonary diseases Embati A.K. Richard Nuclear Medicine Unit Mulago Hospital

THE NUCLEAR MEDICINE UNIT MULAGO NATIONAL REFERRAL HOSPITAL KAMPALA UGANDA

What is Nuclear Medicine? Nuclear medicine is a new medical super specialty that uses radio isotopes to diagnose and treat diseases in a safe and painless way. Nuclear Medicine is one of the ways of peaceful use of atomic energy. Other areas include water, mining, animal husbandry and agriculture, energy, industry etc.

Which nuclear medicine techniques are used in human medicine? Diagnostic nuclear medicine imaging Radioimmunoassay Therapeutic nuclear medicine

Nuclear Medicine Nuclear medicine procedures permit the determination of medical information that would be otherwise not available, require surgery or necessitate more expensive and invasive diagnostic tests. NM procedures often identify abnormalities very early in the progression of the diseases – long before some medical problems are apparent with other medical diagnostic tests. This early detection allows a disease to be treated sooner in its course when a more successful prognosis may be possible.

Pertinent information needed. Pathophysiology Clinical presentation Ventilation scans/Perfusion scans Patient management Radio pharmaceuticals Equipment Images Other imaging modalities

The respiratory system

Roles of Lung Scintigraphy Nuclear medicine studies make it possible to identify areas within the lung where ventilation/perfusion changes have occurred, and allow precise quantification of the regional distribution of ventilation and perfusion.

Roles cont Pulmonary embolism as well as in other lung diseases. Evaluation of acute thromboembolism. Primary lung cancer and its metastases can now be visualized with tracers used for the study of myocardial perfusion (sestaMIBI, tetrofosmin) or labeled ocreotide, a molecule able to recognize lung tumors with somatostatin receptors. 99mTc-NR-LU-10 Fab immunoscintigraphy was shown to be very sensitive for tumors. PET in the differential diagnosis of solitary pulmonary nodule, in the initial staging and in the response assessment to lung cancer therapy.

Diagnostic nuclear medicine imaging A physiologically active substance (ligand or pharmaceutical) is attached to a small quantity of radioactive material (a radioisotope) to produce a radiopharmaceutical. There are many radiopharmaceuticals available for diagnostic imaging of various organs of the body. Which radiopharmaceutical is used depends on the condition which is to be diagnosed and or treated.

How do radiopharmaceuticals work? Radiopharmaceuticals are introduced into the body of the individual by: - injection (intravenous, intradermal, intrathecal,intracavitary) - Oral ingestion - inhalation. The amount given is very small.

Radionuclides that can be used to evaluate Lung ventilation Isotopes used in perfusion Half-life Energy (Peak) KeV 99mTc Technegas 6 hours 140 133Xe 5.2 days(5.3days) 81(80) 99mKr 13 Seconds 190 RP used. Tc-99m DTPA aerosol (25-30mCi)

Examples of R/P Tc-99m DTPA used for Renal studies Tc-99m MDP used for Bones studies Tc-99m HMPAO used for Brain studies Ga-67 used for Tumour and infection imaging Tc-99m MIBI for Cardiac imaging Tc-99m MIBG for Adrenal imaging Tc-99m Macroaggregated Albumin for V/Q

EQUIPMENT Nm technology is a dynamic and evolving field. SPECT is widespread in the clinical field with the use of 2-3 head gamma cameras and the possible combined imaging with CT or MRI. SPECT SPECT/CT PET PET/CT

ADVANCES New scanners New tracers :Both diagnostic and Therapy GEMINI TF PET/CT scanner with TruFlight technology

Normal scan

52-year-old woman with acute pulmonary thromboembolism (PTE).

v/p mismatch

COPD Perfusion Ventilation

SARCOIDOSIS Lambda and panda pattern in a 38-year-old female patient with sarcoidosis.

PCP A 42 year old homosexual male presented with a 3 week history of fevers and sweats. He was diagnosed as HIV positive 5 years. CXR was normal. Gallium-67 scintigraphy revealed diffuse lung uptake. Washings from fibreoptic bronchoscopy confirmed pneumocystis carinii (PCP) infection

111In-WBC Physics Energy: 172 (90%), 245 (94%) keV T1/2: 2.8 days Dose: 500 uCi Physiology Migration of WBC Normal biodistribution: liver, spleen, bone marrow, +/- lung Uses: Infection

Physics Energy: 93 (40%), 184 (20%), 300 (17%), 393 (20%) keV T1/2: 78 hrs Dose Infection: 5 mCi Tumor: 10 mCi Physiology Iron analogue Normal biodistribution: liver, spleen, bone, bone marrow, nasopharynx, lacrimal, salivary, GI, (kidney/bladder 1st 24hrs) Uses: Infection, tumor 67Ga Citrate

99mTc-MAA Physics Energy: 140 keV T1/2: 6 hrs Dose: 5 mCi Physiology End arteriole occlusion Normal biodistribution: lung Uses: V/Q, R to L shunt

Therapeutic applications of nuclear medicine(Systemic radiotherapy) targeted therapies using radiolabeled compounds Dependent on beta or alpha emission property of isotope Tumor or abnormal tissue destroyed by internal radiation

Therapeutic techniques used Nuclear Medicine There are a number of therapeutic techniques being used in Nuclear Medicine. These are:- Radioiodine therapy of hyperthyroidism using Iodine-131 as Sodium-Iodide. Radioiodine therapy of differentiated thyroid carcinoma using Iodine-131 as Sodium-Iodide. 131I-MIBG therapy for neuroendocrine tumours such as Pheochromocytoma, neuroblastoma etc. Adjuvant radionuclide therapy of peritoneal metastases using 32Phosphorus-colloid. Radionuclide therapy of recurrent malignant ascites using 198Au-colloids. Radionuclide therapy of malignant pleural effusion using 32Phosphorus-colloid. Radionuclide therapy of bone pain using 32Phosphorus, Samarium-153 EDTMP, Strontium-89 Chloride, Rhenium-186 HEDP, Yttrium-90 citrate.

Therapy cont Radionuclide therapy of malignant pericardial effusion using 198Au-colloid. Radionuclide therapy of cystic brain tumours using 34Phosphorus Chromic phosphate suspension. Radionuclide therapy in joint diseases such as Rheumatoid arthritis using 90Yttrium-colloids, 32Phosphorus-colloids. Radioimmunotherapy for Non-Hodgkin’s lymphoma using Zevalin or Bexxar. Intra-arterial radionuclide therapy using 90Yttrium-microspheres for microscopic liver metastases. Radionuclide therapy for histological confirmed, inoperable primary hepatocellular carcinoma using 131I-Ethiodised oil (Lipiodol). Intrathecal radiocolloids in meningeal leukemia using 198Au-colloid.

153Sm-EDTMP Physics Energy: 103 keV g T1/2: 46 hrs Dose: 1 mCi/kg Physiology EDTMP like MDP Normal biodistribution: bone, bladder, kidney Uses: treatment of painful bony mets Comment: can image

Iodine 131 therapy Radioiodine has been applied in millions of patients with benign and malignant thyroid diseases for >50 years When administered systemically, I-131 is concentrated in thyroid tissue, achieving high intrathyroidal radiation doses thereby generating a therapeutic effect due to the emission of charged particles (electrons, β radiation) Due to the limited range, the cervical soft tissues are spared I-131 accumulates in a given follicle, irradiates integral cellular structures such as cytoplasm and nucleus and may also irradiate neighboring cells and follicles causing their death – medical thyroidectomy

Successful treatment of pulmonary metastases of pT4N1M1 papillary thyroid carcinoma by repetitive high-dose I-131 infusions. A-Before B-after 2 doses C-after 3 doses Successful treatment of pulmonary metastases of pT4N1M1 papillary thyroid carcinoma by repetitive high-dose I-131 infusions. (A). I-131 scintigraphy before treatment: diffuse pulmonary uptake of I-131 due to diffuse lung metastases. (B) I-131 scintigraphy after two administrations of I-131: decrease of the pulmonary uptake indicating response of the lung metastases. (C) I-131 scintigraphy after three administrations of I-131: no abnormal pulmonary uptake indicating complete response. Oyen W J G et al. Ann Oncol 2007;18:1782-1792 © 2007 European Society for Medical Oncology

GI Lymphoma monitoring of treatment... A 61-year-old woman with large cell lymphoma. A: Pre-treatment 18F-FDG PET scan revealed multifocal hypermetabolic activity involving the neck, chest, and abdomen (arrow). B: Followup 18F-FDG PET scan 5 mo later showed no evidence of residual FDG disease. A 68-year-old man with large cell lymphoma. A: Base line 18F-FDG PET scan showed hypermetabolic foci in the stomach (white arrow), cecum and terminal ileum (black arrow), and bowel loops B: 18F-FDG PET scan obtained after therapy showed partial metabolic response of the activity in the stomach (white arrowhead) and cecum (black arrowhead,

Nuclear medicine therapy for solid tumors Solid cancers have generally lower radiosensitivity. They are targeted less efficiently with radiolabeled antibodies than lymphoma due to limited vascularization, elevated interstitial pressure and heterogeneous uptake of the radiolabeled antibody minimal residual disease is most favorable for treatment with radiolabeled antibodies.

Conclusion Nuclear Medicine plays a role in management of Lung diseases. A multi disciplinary skills and approach is needed. Our main challenges currently include understaffing due to difficulties in recruitment and only one Single head SPECT gamma camera

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