AOBNM Nuclear Medicine cheat sheet

Tc-99m: 6-hour physical half-life, 140 keV gamma emission; eluted from a Mo-99/Tc-99m generator; transient equilibrium sets practical elution limits (~24 h) and limits the useful generator lifespan (~1-2 weeks).

Effective half-life: 1/Teff = 1/Tphysical + 1/Tbiologic; governs dose-rate and imaging windows (e.g., I-123 thyroid uptake with 13 h physical and shorter biologic).

Radiation dose to tissue depends on administered activity, residence time, and energy per decay; use the MIRD schema (S-value × cumulated activity) rather than activity alone.

Ventilation/perfusion (V/Q) mismatch: perfusion defect with preserved ventilation suggests pulmonary embolism; matched defects suggest parenchymal disease (COPD, pneumonia).

Ventilation agents: Tc-99m DTPA aerosol (small droplets, good peripheral penetration) vs. Technegas (ultrafine carbon particles, better peripheral deposition in COPD).

Bone scan: Tc-99m MDP; uptake proportional to osteoblastic activity and blood flow; superscan = diffuse high skeletal uptake with faint renal/soft-tissue uptake (e.g., widespread metastases, metabolic bone disease).

Renal scan: Tc-99m MAG3 (tubular secretion, preferred for function/transplant) vs. Tc-99m DTPA (glomerular filtration); captopril renography for renovascular hypertension.

Thyroid: I-123 for uptake/scanning (pure gamma emitter) vs. I-131 for therapy (beta + gamma); uptake increased in Graves disease, decreased in subacute thyroiditis and exogenous hormone.

Hepatobiliary: Tc-99m mebrofenin/IDA; gallbladder nonvisualization at 60 min with normal hepatic uptake suggests acute cholecystitis; also used for biliary leak.

Four tenets: body is a unit; structure and function are reciprocally interrelated; body is self-regulating/self-healing; rational treatment is based on these principles.

Somatic dysfunction: impaired or altered function of related components of the somatic (body framework) system - skeletal, arthrodial, and myofascial - plus related vascular, lymphatic, and neural elements.

TART mnemonic for somatic dysfunction: Tissue texture changes, Asymmetry, Restriction of motion, Tenderness.

Viscerosomatic reflexes: visceral afferents converge on the same spinal cord levels as somatic afferents, producing segmental tissue texture changes, tenderness, and restricted motion at corresponding levels.

Sympathetic innervation levels: T1–L2; parasympathetic via cranial nerves (III, VII, IX, X) and S2–S4; correlate with organ-based reflex patterns.

Chapman points: anterior and posterior reflex points (lymphatic/visceral) used diagnostically and therapeutically; distinct from trigger points and from segmental viscerosomatic findings.

Lymphatic techniques (e.g., thoracic inlet, abdominal diaphragm, pelvic diaphragm release) promote venous/lymphatic return and may be relevant in patients with edema or post-surgical lymphatic impairment.

Contraindications to OMT: acute fracture, dislocation, severe osteoporosis, bone malignancy/metastatic disease, joint instability, and acute infection of the affected region - screen before treatment.