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NUCS DDX Scan Dose/Radiopharmaceutical Tracer T1/2 Energies Decay Bone 20 mCi Tc-99m-MDP Tc-99m 6 hr 140 keV IT Lung 4 mCi Tc-99m-MAA, 20 mCi Tc-99m-DTPA I-123 13.3 hr 159 keV EC Heart 3 mCi Tl-201, 20 mCi Tc-99m-mibi I-131 8.1 d 365 keV* beta RVG 20 mCi Tc-99m-RBC In-111 2.8 d 172, 247 keV EC Thyroid 300 uCi PO I-123 or 10 mCi IV Tc-99m-O4 Ga-67 78 hr 90,190,300,390 EC 4 mCi I-131 Co-57 270 d 122, 136 keV EC Parathyroid 20 mCi Tc-99m-mibi Cr-51 28 d 320 keV EC Renal 4 mCi Tc-99m-DTPA or 5 mCi Tc-99m-MAG3 F-18 110 min 511 keV positron Testicular 10 mCi Tc-99m-O4 Xe-133 5.3 d 81 keV beta Liver-spleen 3 mCi Tc-99m-sulfur colloid Tl-201 73 hr 69-83 keV EC Liver (blood pool) 20 mCi Tc-99m-RBC Xe-127 36.4 d 172,203,375 Hepatobiliary 1 mCi Tc-99m-DISIDA * # of days in the year Brain 20 mCi Tc-99m-ECD or Tc-99m HMPAO Infection 10 mCi Ga-67 citrate or 500 uCi In-111 WBC or 5 mCi Tc-99m-HMPAO WBC (small bowel) GI bleed 20 mCi Tc-99m-RBC Meckel’s 10 mCi Tc-99m-O4 Gastric emptying 250 uCi PO Tc-99m-sulfur colloid Lymphoscintigraphy 800 uCi SC Tc-99m-sulfur colloid (4 deep, 4 superficial) Tumor 10 mCi FDG-18; 10 mCi Ga-67 citrate; 500 uCi I-131 MIBG;5 mCi In-111-octreotide QA: Al breakthrough <10 ug/ml; Mo breakthrough <0.15 uCi/1 mCi Tc99m; Mo breakthrough determined by counting eluate in well counter without and with lead shield; radiochemical purity determined with thin layer chromatography, free Tc04 migrates in saline and methanol, Tc99m compounds migrate in saline only; daily - extrinsic flood with collimator with Co57 sheet source (10 million counts), intrinsic flood without collimator with Tc-99m-O4 point source at ceiling; weekly – bar phantom; biweekly – SPECT floods (120 million counts) Poor image quality: wrong photopeak, patient too far from collimator, wrong type of collimator, wrong isotope, cracked crystal, cracked photo-multiplier tube, tracer contamination on crystal PIOPED criteria: high prob (>80%) - >2 large (>75%) segmental V/Q mismatches or arithmetic equivalent in moderate or large and moderate defects; intermediate prob (20-79%) – 1 moderate (25-75%) to 2 large segmental V/Q mismatches or arithmetic equivalent, single matched V/Q defect with clear CXR, triple matched defects; low prob (<20%) – nonsegmental perfusion defects, any perfusion defect with substantially larger CXR abnormality, matched V/Q defects with normal CXR, any number of small (<25%) perfusion defects with normal CXR; normal – no perfusion defects V/Q mismatch: acute PE, old PE, tumor compression of PA (more rigid bronchi tend to remain patent), hypoplastic PA, vasculitis, atelectasis (reverse mismatch), sickle cell dz. Matched V/Q defects: consolidation, COPD, atelectasis, tumor, bulla, pneumonectomy Lung scan (other): clumped MAA, stripe sign, fissure sign; R to L shunt – activity in kidneys and brain; central deposition of DTPA – COPD; liver uptake on perfusion study – SVC obstruction; liver uptake on ventilation study – fatty liver; delayed washin and washout on Xe study – air trapping; Xe leak – BPF Unilateral ↓V/Q: hilar mass (lung CA or adenopathy), severe unilateral parenchymal lung dz, Swyer-James syndrome, hypoplastic pulmonary artery, prior shunt for CHD, asc. Ao aneurysm, pneumonectomy Cardiac: perfusion defects – reversible is ischemia, fixed is infarct or hibernating; wall motion – normal, akinesis (scarred), hypokinesis (injured), dyskinesis (paradoxical wall motion, CABG, aneurysm), tardokinesis; RUG – adriamycin stopped if EF<45% or drops 15% Stress test endpoints: severe angina, hypotension, arrhythmias, AMI, fatigue, dyspnea, target workload achieved Pharmacologic stress: unable to exercise, use persantine (0.142 mg/kg/min) or adenosine, reverse with theophylline (50-100mg), use dobutamine if COPD on theophylline; use pharmacologic stress for LBBB (o/w may see reversible septal defect) Increased lung uptake on thallium: LV failure, pulmonary venous HTN Viable myocardium: normal, reversible defect, fixed defect with >50% tracer uptake of normal myocardium; hibernating – blood flow and function chronically reduced; stunned – blood flow normal and function reduced False negative thallium: submaximal exercise, noncritical stenosis, small ischemic area, medications False positive thallium: any cardiomyopathy, LBBB, infiltrative cardiac disease, ST attenuation Paradoxical septal movement: septal ischemia, previous cardiac surgery, LBBB or pacemaker, RV overload Pyrophosphate uptake: MI, LV aneurysm, cardiomyopathy, myocarditis, pericarditis, amyloid GB not visualized: acute cholecystitis, fasting <4 or >24 hrs., cholecystectomy, GB agenesis, hyperalimentations, pancreatitis Biliary system not visualized: biliary atresia, long-standing bile duct obstruction ↓GB ejection fraction (>35% is normal; give CCK as 30min. drip infusion): biliary dyskinesia, chronic cholecystitis Low hepatic and renal activity: severe liver disease, neonatal hepatitis Bowel not visualized (delayed biliary-to-bowel transit): chronic cholecystitis, choledocholithiasis, partial biliary obstruction, CCK given pre-scan Abnormal tracer collections: bile leak, choledochal cyst, Caroli’s, duodenal diverticulum; rim sign specific for acute cholecystitis False negative HIDA: acalculous cholecystitis, duodenal diverticulum simulating GB, accessory cystic duct False positive HIDA: recent meal (<4hrs), prolonged fasting (>24hrs), liver dysfunction, hyperalimentation, cystic duct cholangiocarcinoma, pancreatitis, alcoholism Pharmacologic HIDA: if GB not seen in 60 min, can give morphine 0.04 mg/kg (2-3mg) and scan for additional 30 min, but don’t give if morphine allergy or CD obstruction; if bowel not seen at 60 min, can give CCK 0.02 ug/kg (1-2ug) and scan additional 30 min, also can evaluate GB EF (30% in 30 min), can give CCK prior to scan if distended; phenobarbitol 5 mg/kg/day x 5 days prior to scan for biliary atresia (enhances biliary uptake and excretion since hepatic insufficiency from any cause may result in ↓ biliary uptake) and delayed scan up to 24 hrs. Non-obstructive causes of neonatal jaundice will demonstrate biliary to bowel transit by 24 hrs. but biliary atresia will not (next step Kasai procedure). Sulfur colloid (localizes to Kupffer cells): focal liver uptake - FNH, regenerative nodule, Budd-Chiari (hot caudate), SVC or IVC obstruction; renal transplant uptake – rejection; colloid shift into marrow, spleen, lungs, kidneys – severe liver dysfunction; all hepatic masses cold except for FNH; filtered SC for sentinel node study – breast, melanoma HIDA: FNH shows rapid uptake whereas HCC shows delayed uptake. Most other lesions are photopenic. Blood pool: hemangioma (2cm); if immediate uptake consider hypervascular met; heat damaged rbc – splenic remnant, splenosis, accessory spleen GI bleed scan: sensitivity 0.1 ml/min; uptake conforming to bowel with no change over time – IBD, TcO4 excreted into bowel; uptake conforming to bowel with progressive accumulation over time -–hemorrhage; uptake not conforming to bowel – aneurysm RLQ activity on Meckel scan: Meckel’s diverticulum with ectopic gastric mucosa (25%), other duplication cyst with ectopic gastric mucosa, renal, active bleeding sites, hypervascular tumor, IBD; prep with pentagastrin and cimetidine Gastric emptying: 50% in 50 min; delayed – diabetic gastroparesis, obstruction; rapid - postoperative, PUD, ZE syndrome, drugs Focal renal cold defects: tumor, cyst, abscess, scar, duplex collecting system, trauma, infarct; DMSA – pyelonephritis, scar Focal hot renal lesions: collecting system, leak, cross-fused ectopic, horseshoe Dilated ureter or collecting system: reflux (most common), obstructed or nonobstructed ureter (Lasix renogram to distinguish, delayed parenchymal clearance >20min) Delayed uptake and excretion (renal failure): prerenal – poor flow and uptake, unilateral, RAS (ascending pattern with captopril, beware of hypotension), RVT; renal – bilateral, ATN (nl uptake, poor excretion), GN (poor uptake and excretion), CRF; postrenal – obstruction Nonvisualized kidney: nephrectomy, ectopic kidney, renal artery occlusion, hyperacute rejection in transplant Renal transplant complications: ATN (preserved flow), cyclosporine toxicity, acute rejection (decreased flow), obstruction, urinoma, lymphocele, hematoma, abscess, RAS/RVT Decreased testicular uptake: torsion, orchiectomy, hematoma, hydrocele Increased testicular uptake: epididymoorchitis, torsion of testicular appendix, minor trauma, spontaneous detorsion Must ask side of pain in Tc-O4 testicular scan or may give false dx; pre-tx with oral K04 to protect thyroid gland Ring sign: late torsion, tumor with central necrosis, abscess, trauma (hematoma) Focal hot bone lesions: tumor; inflammation – osteomyelitis, arthritis; congenital – OI, TORCH; metabolic – marrow hyperplasia, Paget’s, FD; trauma – fracture (rib fxs linear distribution), stress fx (e.g. Honda sign), avulsion injury, AVN, RSD (Sudeck’s atrophy), THR (negative within 6 mos), spondylolysis, child abuse; vascular – sickle cell; transient osteoporosis of hip; flare phenomenon – good response to chemotherapy Focal cold bone lesions: (MR. NEAT) mets most common – myeloma, lymphoma, renal, thyroid, neuroblastoma; primary bone lesions – SBC, ABC, EG; vascular – infarction, AVN (get pinhole view), radiation; artifact – overlying pacemaker, barium, jewelry, prosthesis Positive 3-phase bone scan: osteomyelitis, healing fx, tumor, orthopedic implants, AVN (SONK), RSD, neuropathic osteoarthropathy; cellulitis – flow and blood pool positive, delayed negative; shin splints – flow and blood pool negative, delayed positive Superscan: diffuse high bone uptake, diminished soft tissue and renal activity, high sternal uptake, increased uptake at costochondral junction; mets (usu focal) – prostate (most common – axial predominance of lesions), breast, lung; metabolic – HPT, renal osteodystrophy, osteomalacia, Paget’s (hot and cold); myelofibrosis (large spleen), mastocytosis, hypervitaminosis D Increased renal uptake on WBBS (defined as renal>spine uptake): urinary tract obstruction, dehydration, chemotx (doxorubicin, vincristine, cyclophosphamide), nephrocalcinosis, hypercalcemia, radiation nephritis, ATN, thallassemia, aluminum contamination (rare), recent IV contrast Unilateral chest uptake on WBBS: malignant pleural effusion (#1), fibrothorax, XRT, pleural Ca2+, lung CA, ST mass Bilateral chest uptake on WBBS: metastatic calcification 20 renal failure, mets, pleural effusions, XRT, alveolar microlithiasis Splenic uptake on WBBS: sickle cell (#1), thalassemia, hemosiderosis, subcapsular splenic hematoma Diffuse periosteal uptake (tramtrack): HPO, child abuse, venous insufficiency, thyroid acropachy Extraosseous activity on bone scan: soft tissues – cellulitis, renal failure, radiotherapy ports, myositis ossificans, muscle injury, dermatomyositis, rhabdomyolysis, tumors with calcifications, neuroblastoma in child, sinusitis, SVC obstruction (upper body), IVC obstruction (lower body), lymphedema (arm + anterior ribs); injection abnormalities – infiltration, scatter, lymph node uptake, intraarterial injection (glove phenomenon); kidney – dehydration (most common cause), urinary tract obstruction, hypercalcemia, chemotherapy, radiation, Al contamination; breast – pregnancy, lactation, mastitis, inflammatory breast CA, steroids, radiation; stomach, GI – free TcO4, HPT, hypercalcemia, bowel infarction, prior MIBI scan; liver – mets, prior sulfur colloid scan, Al contamination; spleen – sickle cell, thalassemia, breast CA, lymphoma; lung – HPT, lung tumor, pulmonary hemosiderosis, alveolar microlithiasis, metastatic osteosarcoma, prior lung scan; pleural – malignant pleural effusion, pleural met, mesothelioma, chest wall tumor, fibrothorax; heart – MI, CM, myocarditis, pericarditis, amyloid; other – brain infarction, urine in socks contamination, skin contamination, vascular calcification, calcified fibroid, photopenic bowel from barium; hypercalcemia – increased uptake in lung and stomach and kidney; Al contamination – increased uptake in liver and kidney; excess TcO4 – increased uptake in soft tissues, salivary, thyroid, stomach, choroid plexus, decreased uptake in bone; bisphosphonates – diffuse decreased uptake in bones; amyloid – diffuse increased uptake in myocardium Diffuse increased thyroid uptake: Graves, early Hashimoto’s thyroiditis, toxic MNG, functioning adenoma (focal) Diffuse decreased thyroid uptake: thyroiditis – subacute, postpartum, late Hashimoto’s; meds – thyroid hormone therapy, iodine intake or contrast, PTU, tapazole; thyroid ablation – surgery, I131; lingual thyroid; unilateral – surgery, replacement by hypofunctioning tumor, suppression by hot nodule, hemiagenesis Heterogeneous thyroid uptake: MNG, multiple autonomous nodules, Hashimoto’s, CA Cold nodule: adenoma/colloid cyst (85%), CA (10%), focal thyroiditis, hemorrhage, lymph node, abscess, parathyroid adenoma I-131 therapy: Graves 10-15 mCi, Plummer’s 30 mCi, residual tissue 30-100 mCi, mets 100-200 mCi Positive parathyroid scan: parathyroid adenoma, thyroid adenoma (most common false+), lymph node, thyroid CA, mets Negative parathyroid scan: parathyroid hyperplasia Gallium positive scan: sarcoid (lambda and panda sign), PCP, lymphoma (thallium better for low-grade), osteomyelitis (better than wbc study for discitis/osteomyelitis), amyloid, parotid, lacrimal; KS is gallium(-)/thallium(+); increased lung uptake – sarcoid, PCP, TB, MAI, CMV, lymphoma, chemotherapy (bleomycin), lipiodol; increased parotid and lacrimal uptake – sarcoid, Sjogren’s, radiation Diffuse decreased gallium activity: hemochromatosis, iron overload, post-chemotherapy WBC scan: all infections in abdomen, osteomyelitis, vascular graft infection Neuroendocrine tumors: MIBG (esp pheochromocytoma, give Lugol’s to protect thyroid), octreotide (hot spleen and kidneys) PET indications: SPN, NSCLC, melanoma, lymphoma, colorectal, residual/recurrent brain tumor vs radiation necrosis PET of SPN: false negative – small nodule <1cm, BAC, carcinoid; false positive – benign tumor, inflammation, infection Brain death: no flow to cerebral cortex, can get hot nose sign Focal brain cold defect: infarct, neoplasm, hemorrhage, crossed cerebellar diaschisis (contralateral cerebellum no uptake after stroke), interictal siezure focus; diagnostic patterns – Alzheimer’s (temporal, parietal), Pick’s (frontal, temporal), multiinfarct dementia Cisternogram: 500 uCi In-111 DTPAintrathecal; evaluate for NPH (activity in lateral ventricles), CSF leak (check nasal pledgets), CSF shunt patency Lymphoscintigraphy: Used to define lymphatic drainage of melanoma and breast CA in identifying the sentinel node, or first draining node of a regional nodal basin. Lymphatic spread of tumor cannot have occurred if the sentinel node is not positive for mets using gamma probe for intraop localization. Use 0.25 mCi of 0.22 µm filtered Tc-99m sulfur colloid. Intracutaneous injxn for melanoma; intra or subcutaneous for breast CA. Bone Uptake: Tc-MDP, Tc-sulfur colloid, Ga67, WBC agents – In oxine and Tc HMPAO Myocardial Uptake: Tl-201, Tc (mibi, tetrofosmin, teboroxime), MIBG, FDG-PET; beware Ga67 in myocarditis Liver, spleen, BM uptake: Tc-sulfur colloid (liver>spleen unless colloid shift), WBC study (In-111 (higher dosimetry) or Tc-HMPAO (better resolution)), Gallium
