NRRPT Internal Dosimetry and Bioassay 2

Question 1

Which analytical technique is commonly used for indirect bioassay of uranium in urine samples?

Accepted Answer

Fluorometric analysis or ICP-MS

Answer

Uranium is detected in urine via fluorometric analysis or inductively coupled plasma mass spectrometry (ICP-MS) because natural uranium emits very weak radiation.

Question 2

What ICRP lung model parameter describes how quickly an inhaled material is cleared from the respiratory tract?

Accepted Answer

Absorption type (F, M, or S)

Answer

The ICRP Human Respiratory Tract Model classifies inhaled materials as Fast (F), Moderate (M), or Slow (S) based on their rate of absorption into blood.

Question 3

A whole-body counter (WBC) is most sensitive for detecting which type of emitter inside the body?

Accepted Answer

Gamma emitters

Answer

WBCs detect gamma photons penetrating the body using NaI or HPGe detectors, making them most useful for gamma-emitting radionuclides.

Question 4

Which organ is the critical organ for dosimetry purposes when a worker inhales tritium (H-3) as HTO?

Accepted Answer

Whole body (uniform distribution)

Answer

Tritiated water (HTO) rapidly distributes uniformly throughout body water, so the whole body is used as the reference tissue for dose calculations.

Question 5

What is the effective half-life (T_eff) of a radionuclide in the body?

Accepted Answer

The combined half-life accounting for both physical decay and biological elimination

Answer

T_eff = (T_physical × T_biological) / (T_physical + T_biological), combining radioactive decay with the body's elimination rate.

(NRRPT) National Registry of Radiation Protection Technicians Practice Test

(NRRPT) National Registry of Radiation Protection Technicians Practice Test

NRRPT Internal Dosimetry and Bioassay 2