CPHON Radiation Therapy in Pediatric Oncology 1 — Questions and Answers
Question 1: What is the standard SI unit used to measure absorbed radiation dose in radiation therapy?
- Roentgen
- Gray (Gy) (Correct answer)
- Sievert (Sv)
- Rad
Correct answer: Gray (Gy)
The Gray (Gy) is the SI unit of absorbed radiation dose, defined as 1 joule of energy absorbed per kilogram of tissue.
Question 2: Which type of radiation therapy delivers radiation from a source placed directly inside or adjacent to the tumor?
- External beam radiation therapy (EBRT)
- Proton beam therapy
- Brachytherapy (Correct answer)
- Stereotactic radiosurgery (SRS)
Correct answer: Brachytherapy
Brachytherapy places a radioactive source inside or near the tumor, delivering a high local dose while limiting exposure to surrounding healthy tissue.
Question 3: Which pediatric brain tumor most commonly requires craniospinal irradiation as part of its treatment?
- Pilocytic astrocytoma
- Medulloblastoma (Correct answer)
- Craniopharyngioma
- Ependymoma
Correct answer: Medulloblastoma
Medulloblastoma carries a high risk of leptomeningeal dissemination via cerebrospinal fluid, making craniospinal irradiation a standard component of treatment.
Question 4: What is the primary advantage of proton therapy over conventional photon radiation in pediatric oncology patients?
- Lower treatment cost and wider availability
- Shorter overall treatment duration
- Reduced exit dose and significantly less radiation to healthy surrounding tissues (Correct answer)
- Higher tumor kill rate than photon therapy
Correct answer: Reduced exit dose and significantly less radiation to healthy surrounding tissues
Protons deposit maximum energy at the Bragg peak and produce minimal exit dose, dramatically reducing radiation exposure to healthy tissues beyond the tumor—critical in growing children.
Question 5: According to the CTCAE grading scale, which finding characterizes grade 2 radiation dermatitis?
- Faint erythema with dry desquamation
- Moderate to brisk erythema with patchy moist desquamation in skin folds (Correct answer)
- Confluent moist desquamation over areas of trauma
- Skin necrosis requiring surgical intervention
Correct answer: Moderate to brisk erythema with patchy moist desquamation in skin folds
Grade 2 radiation dermatitis is defined by moderate to brisk erythema with patchy moist desquamation, primarily confined to skin folds.
Question 6: Which of the following is an acute side effect of radiation therapy directed to the head and neck region in a pediatric patient?
- Secondary malignancy
- Growth hormone deficiency
- Mucositis (Correct answer)
- Cognitive processing deficits
Correct answer: Mucositis
Mucositis is an acute side effect of head and neck radiation that typically appears within the first 1–2 weeks of treatment due to injury to rapidly dividing mucosal cells.
Question 7: What is the most appropriate nursing recommendation for managing radiation-induced fatigue in a school-age child?
- Enforce strict bed rest throughout the entire treatment course
- Prohibit all physical activity to conserve energy reserves
- Schedule important activities during peak energy periods and encourage light exercise as tolerated (Correct answer)
- Routinely administer stimulant medications to maintain alertness
Correct answer: Schedule important activities during peak energy periods and encourage light exercise as tolerated
Energy conservation strategies combined with light physical activity during periods of highest energy best manage radiation-induced fatigue without causing deconditioning.
CPHON Radiation Therapy in Pediatric Oncology 1
What is the standard SI unit used to measure absorbed radiation dose in radiation therapy?