BCNP cheat sheet

Radionuclide purity = fraction of total activity from the desired radionuclide; assess by gamma spectroscopy, and verify that contaminant peaks fall below the stated limit before release.

Radiochemical purity = fraction of total activity in the desired chemical form; measure by chromatography (paper, TLC, or HPLC) and compute as (activity in product peak / total activity on strip) × 100.

Radionuclidic identity is confirmed by measuring half-life: for Tc-99m, activity should halve every 6.01 h; a measured half-life within roughly 5.7-6.3 h is acceptable.

99Mo breakthrough limit for Tc-99m eluate is 0.15 kBq of Mo-99 per MBq of Tc-99m (0.15 µCi Mo-99 per mCi Tc-99m); test every elution with a Mo-99 breakthrough detector or dose calibrator ratio method.

Alumina column generators: 99Mo binds as molybdate; 0.9% NaCl elutes pertechnetate (TcO4-); wet-column generators require elution at least every 24 h to limit Mo-99 buildup and radiolysis.

Dose calibrator constancy checks use a long-lived reference source (Cs-137 or Co-57) daily; accuracy checks compare measured vs. decay-corrected activity within ±5-10% across commonly used radionuclides.

Decay formula: A(t) = A0 × e^(-0.693 t / T½); precalibration correction uses A0 = A(t) × e^(+0.693 t / T½) where t is time from calibration to use.

Effective half-life: 1/Teff = 1/Tphysical + 1/Tbiological; it governs cumulative absorbed dose and retained activity over time.

ALARA dose limits (occupational): 50 mSv/y whole-body effective dose; lens 150 mSv/y; extremities/skin 500 mSv/y; declared pregnant worker 0.5 mSv in gestation - apply time, distance (inverse square), and shielding.

Parenteral radiopharmaceuticals are prepared aseptically under a vertical laminar flow hood (ISO Class 5) within a controlled environment; use syringe shields, lead pigs, and dose calibrators to limit exposure.

Patient dose verification: measure the syringe activity in the dose calibrator before administration, record the assay time, and confirm the prescribed activity after decay correction to administration time.

Common kit labeling: Tc-99m MDP for bone, Tc-99m DTPA for renal/GFR, Tc-99m sulfur colloid for liver/spleen, Tc-99m MAA for lung perfusion, Tc-99m sestamibi for myocardial perfusion; follow each kit's specified activity, volume, and heating/incubation conditions.

Radiopharmaceutical quality control includes visual inspection for particulates and color, pH, radiochemical purity, radionuclidic purity, sterility, and bacterial endotoxin testing as applicable.

Radioactive decay and exposure: dose rate falls with the square of distance; a 2 cm lead shield attenuates Tc-99m (140 keV) substantially, and shielding choice depends on photon energy and radionuclide.

Waste handling: store radioactive waste until decayed to background (typically 10 half-lives), segregate by half-life, and document decay-in-storage before disposal.

Documentation: each elution and kit preparation records generator serial number, eluate activity, time, volume, Mo-99 breakthrough result, and technologist identity; retain per regulation.

Patient instructions for common studies: hydrate and void for renal scans, void before pelvic imaging, and follow specific fasting or thyroid-blocking instructions when iodine isotopes are used.