ABR NMP flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Tc-99m half-life

6.01 hours; emits 140.5 keV gamma; most common SPECT tracer; parent Mo-99 (66 h) in generator; eluted as pertechnetate.

F-18 half-life

109.8 minutes; positron emitter (β⁺ max 634 keV); used in FDG PET; annihilation produces two 511 keV photons emitted ~180° apart.

Anger logic

Position calculation in gamma camera: X = Σ(E_i x_i)/ΣE_i, Y = Σ(E_i y_i)/ΣE_i; energy Z = ΣE_i used for photopeak window.

Collimator resolution formula

R_coll ≈ d(l_eff + b)/l_eff where d = hole diameter, l_eff = effective length, b = source-collimator distance; smaller holes and longer collimators improve resolution but reduce sensitivity.

PET random coincidence rate

R_random = 2τS₁S₂, where τ is the coincidence timing window and S₁, S₂ are singles rates in each detector; randoms increase with activity squared.

NaI(Tl) energy resolution

Typically 6–7% FWHM at 140 keV for Tc-99m; improves with higher light output and better PMT coupling; used to set photopeak window (±10%).

MIRD absorbed dose

D = à · S, where à is cumulated activity (Bq·s) and S is absorbed dose per unit cumulated activity (Gy/Bq·s); S values tabulated per radionuclide and source-target pair.

HVL and attenuation

Half-value layer HVL = ln(2)/μ = 0.693/μ for narrow-beam geometry; intensity I = I₀ e^(−μx); used in shielding design and dose estimates.

Photopeak window

Energy acceptance range centered on photopeak (e.g., 126–154 keV for Tc-99m, ±10%); excludes Compton scatter; wider window increases sensitivity but degrades contrast.

Uniformity QC

Daily flood image assesses detector uniformity; integral uniformity = (max−min)/(max+min)×100% over useful FOV; differential uniformity compares adjacent pixels.

Sensitivity

Counts per unit activity (cps/MBq or cpm/μCi); measured with a known source; depends on collimator, energy window, and detector efficiency.

PET normalization

Correction for detector efficiency variations; performed with a uniform cylinder or rotating source; essential for quantitative PET; daily QC includes blank scan and normalization check.

Scatter correction

SPECT: energy window or dual-energy-window methods; PET: delayed-window or model-based; improves contrast and quantitation; over-correction increases noise.

Attenuation correction

SPECT: CT-based or transmission scan; PET: CT or transmission; required for quantitative uptake (e.g., SUV); incorrect AC causes artifacts and bias.

SUV

Standardized uptake value = tissue activity concentration × body weight / injected dose (decay-corrected); used in PET oncology; depends on AC, scanner calibration, and uptake time.

Dead time

Loss of counts at high rates; paralyzable model: m = n e^(−nτ); nonparalyzable: m = n/(1+nτ); affects quantitative accuracy; measured with decaying source.

Radiochemical purity

Fraction of total radioactivity in the desired chemical form; assessed by chromatography (ITLC, HPLC); must meet pharmacopeial limits before patient administration.

Generator elution

Mo-99/Tc-99m generator: Tc-99m eluted with saline; Mo-99 breakthrough limit ≤0.15 kBq Mo-99 per MBq Tc-99m; elution efficiency and time since last elution affect yield.

Informed consent elements

Purpose, risks, benefits, alternatives, confidentiality, right to withdraw, contact information; documented in record; special rules for minors and decisionally impaired.

Belmont Report principles

Respect for persons, beneficence, and justice; foundation for human-subjects research ethics; IRB applies these to protocol review.

HIPAA minimum necessary

Use or disclose only the minimum protected health information needed for the purpose; applies to treatment, payment, and operations; exceptions for treatment disclosures.

Conflict of interest

Financial or personal interest that could bias professional judgment; must be disclosed and managed (recusal, divestment) per institutional policy.

Scope of practice

Legal and ethical boundary of professional duties; provide only services for which you are credentialed and competent; refer outside expertise.

Mandatory reporting

Legal duty to report suspected abuse, impaired colleagues, or serious safety events to designated authorities; failure may carry civil or criminal liability.

ALARA principle

As Low As Reasonably Achievable; optimization of radiation protection considering economic and social factors; applied to occupational and patient exposures.

Justification principle

No radiation exposure without net benefit; medical exposures must be justified by referring clinician and radiologist; research exposures require ethics review.

Dose limits

Occupational: 50 mSv/y effective; public: 1 mSv/y; lens 150 mSv/y (occupational); pregnancy declared: 0.5 mSv/month fetal; institutional constraints often lower.

Data integrity

Accurate recording, retention, and reporting of research and clinical data; avoid fabrication, falsification, and plagiarism; correct errors transparently.

IRB approval

Institutional Review Board reviews human-subjects research for risk/benefit, consent, and equity; ongoing review and reporting of adverse events required.

Patient autonomy

Respect for patient's right to make informed decisions, including refusal; requires capacity assessment and disclosure; overrides paternalism.

Professional competence

Maintain knowledge and skills through continuing education, peer review, and credentialing; practice within evolving standards; document training.

Research misconduct

Fabrication, falsification, or plagiarism in proposing, performing, or reporting research; does not include honest error; reported to institutional officials.