Technical Terminology Practice Test

As used in the passage, the term radiosensitive most nearly means...

A section on pediatric imaging explains why children often receive modified protocols. The passage states that some tissues are more radiosensitive, meaning they are more likely to be harmed by a given radiation dose. Rapidly dividing tissues, such as bone marrow, are highlighted because DNA replication provides opportunities for radiation-induced errors to become fixed as mutations. The passage also notes that children have longer remaining lifespans, giving more time for radiation-related cancers to develop. By describing tissues as radiosensitive, the author is not implying they “sense” radiation consciously; rather, the term indicates biological vulnerability to radiation-induced damage.

As used in the passage, the term ionization most nearly means...

A radiology instructor describes why some forms of radiation are called “ionizing.” Atoms normally contain electrons (negatively charged particles) bound to a nucleus. When an incoming X-ray or gamma-ray photon carries enough energy, it can knock an electron out of an atom, leaving behind a charged atom called an ion. This event—electron removal that creates ions—is ionization. In living tissue, ionization can occur in water molecules, producing reactive fragments such as free radicals, which are chemically aggressive species with unpaired electrons. These radicals may attack DNA, producing strand breaks; if the cell repairs the breaks incorrectly, mutations can accumulate. Because risk depends on how much energy is deposited, clinicians quantify radiation dose and reduce unnecessary exposure by collimation (narrowing the beam), avoiding repeat scans, and choosing non-ionizing alternatives like ultrasound when appropriate. Nonetheless, ionizing radiation has clear benefits: it can reveal fractures, pneumonia, or internal hemorrhage quickly, enabling timely treatment. The passage emphasizes that the same property that makes ionizing radiation useful for imaging—its ability to interact strongly with matter—also underlies its biological hazard.