ARRT Review – Nuclear
Medicine 2026 | Questions,
Answers & Detailed
Rationales Study Guide
|Graded A+ | Guaranteed
success|
Updated 2026 Questions and Answers
100% Verified Exam Prep and Comprehensive
Rationales
Included
,Free radical Is an uncharged molecule that contains a single unpaired electron in its outermost
or valence shell, which it make it chemically unstable and highly reactive
Linear Energy Transfer (LET) describes a measurable of the rate at which energy is deposited as a charge
particle travels through matter.
Low LET radiation Electromagnetic radiation:
X- and Gamma rays
Produce few and sparse interaction because of their fast moving electrons.
High LET radiation Particulate radiation:
Alpha particles and neutrons
Highly ionizing and have substantial mass and/or charge, are more likely to
interact with tissue
Higher; greater the ____________ the LET of radiation, the ______________ the chance for a biological
interaction
Relative Biological Effectiveness (RBE) The relative effect of LET.
Measures the biological effectiveness of radiation having different LETs
Factors that influence RBE -radiation type
-cell or tissue type
-physiologic condition
-biologic result being examined
-radiation dose rate
Stochastic effects Thought to be nonthreshold, as damage to a few cells or even a single cell could
theoretically produce the disease
, Stocastic effects Associated with linear and linear quadratic dose response curves, therefore, even
small exposure could carry some increased risk
Ex. Radiation-induced cancer and genetic effect
Deterministic effects Also known as nonstochastic
Are thought to be threshold, as there are doses below which the effect is not
observed
Ex. Cataracts, erythema, fibrosis and hematopoetic damage
Hemopoietic acute effect 100 - 1,000 R will damage this system, also known to be the bone marrow system
Gastrointestinal acute effect 600 - 10,000 R damage this system, especially the small intestine
Central nervous system acute effect >10,000 R will damage this system, but also starting at a dose of >5,000 R
Somatic Mutations have consequences for only that person
Genetic Mutations can affect reproductive organs or the parents gametes, which may
affect future generation. It's cumulative.
Law of Bergonie and Tribondeau immature cells are significantly more radiosensitive than are mature cells
Immature cells Are known as undifferentiated, precursor or stem cells
Radiosensitive Mitosis and the passage from G1, into early S-phase, are judged to be the most.
Radioresistant Mid- to late S-phase is considered to be the most
Medicine 2026 | Questions,
Answers & Detailed
Rationales Study Guide
|Graded A+ | Guaranteed
success|
Updated 2026 Questions and Answers
100% Verified Exam Prep and Comprehensive
Rationales
Included
,Free radical Is an uncharged molecule that contains a single unpaired electron in its outermost
or valence shell, which it make it chemically unstable and highly reactive
Linear Energy Transfer (LET) describes a measurable of the rate at which energy is deposited as a charge
particle travels through matter.
Low LET radiation Electromagnetic radiation:
X- and Gamma rays
Produce few and sparse interaction because of their fast moving electrons.
High LET radiation Particulate radiation:
Alpha particles and neutrons
Highly ionizing and have substantial mass and/or charge, are more likely to
interact with tissue
Higher; greater the ____________ the LET of radiation, the ______________ the chance for a biological
interaction
Relative Biological Effectiveness (RBE) The relative effect of LET.
Measures the biological effectiveness of radiation having different LETs
Factors that influence RBE -radiation type
-cell or tissue type
-physiologic condition
-biologic result being examined
-radiation dose rate
Stochastic effects Thought to be nonthreshold, as damage to a few cells or even a single cell could
theoretically produce the disease
, Stocastic effects Associated with linear and linear quadratic dose response curves, therefore, even
small exposure could carry some increased risk
Ex. Radiation-induced cancer and genetic effect
Deterministic effects Also known as nonstochastic
Are thought to be threshold, as there are doses below which the effect is not
observed
Ex. Cataracts, erythema, fibrosis and hematopoetic damage
Hemopoietic acute effect 100 - 1,000 R will damage this system, also known to be the bone marrow system
Gastrointestinal acute effect 600 - 10,000 R damage this system, especially the small intestine
Central nervous system acute effect >10,000 R will damage this system, but also starting at a dose of >5,000 R
Somatic Mutations have consequences for only that person
Genetic Mutations can affect reproductive organs or the parents gametes, which may
affect future generation. It's cumulative.
Law of Bergonie and Tribondeau immature cells are significantly more radiosensitive than are mature cells
Immature cells Are known as undifferentiated, precursor or stem cells
Radiosensitive Mitosis and the passage from G1, into early S-phase, are judged to be the most.
Radioresistant Mid- to late S-phase is considered to be the most
