10 exam-style questions with answers and explanations, straight from our 1,030-question bank. Tap an answer to check yourself. When you're ready, take the scored version in the free practice test.
The RTT exam has 230 questions and runs 3 hours 50 minutes.
These 10 free RTT questions are organized by exam domain, so you can see how each part of the Registered Technologist - Radiation Therapy blueprint is tested. Reveal the answer and explanation under each question.
At contrast-enhanced CT simulation, a patient taking metformin has a stable eGFR of 46 mL/min/1.73 m² and no acute kidney injury. Intravenous iodinated contrast is ordered. The department follows the ACR Manual on Contrast Media, and no other reason to interrupt metformin is present. What does ACR guidance recommend for metformin in this situation?
Correct answer: B - Continue it without a routine renal recheck solely for this contrast exposure.
During an on-treatment assessment, a patient reports spending about three quarters of waking hours in bed or a recliner because of cancer-related weakness. The patient can walk a short distance to the bathroom but needs help bathing and dressing and cannot work. Which ECOG performance-status score best describes this function?
Correct answer: C - ECOG 3
Reviewing a new patient's history, the therapist finds a positive fecal immunochemical test (FIT) from colorectal cancer screening. The patient feels well and says a second FIT obtained a week later was negative, so the colonoscopy appointment was canceled. Which explanation accurately addresses the unresolved screening result?
Correct answer: D - The positive FIT still requires colonoscopic follow-up despite the negative repeat.
Two schedules would deliver the same 40 Gy to the same volume of a late-responding normal tissue: 20 fractions of 2 Gy or 10 fractions of 4 Gy. Assume complete repair between fractions and disregard overall-treatment-time effects. For a tissue with a low alpha/beta ratio, why are these schedules not biologically interchangeable?
Correct answer: A - The larger fractions produce greater late-tissue injury at the same total dose.
A vented ionization chamber is used for linac output constancy. Its baseline was 100.0 nC at 100.0 kPa; today's reading is 96.0 nC at 96.0 kPa. Temperature, monitor units, setup, and all other correction factors are unchanged. Neither reading has automatic air-density correction. The physicist's procedure compares pressure-corrected readings with a ±3% action limit. Which interpretation belongs in the QA record?
Correct answer: A - Corrected deviation is 0%; this measurement meets the output criterion.
Daily cone-beam CT for prostate-only treatment shows acceptable bony alignment, but the prostate is 4 mm anterior to its planned position. Bladder and rectal preparation are acceptable, with no meaningful rotation or deformation. The approved protocol permits therapist-applied target translations up to 5 mm, followed by verification imaging. How should the therapist correct this setup?
Correct answer: D - Move the patient 4 mm posteriorly and verify the corrected target position.
A two-field photon plan prescribes 180 cGy per fraction to a calculation point. The required dose contributions from fields A and B are in a 2:1 ratio. For field A, open-field output at dmax is 1.00 cGy/MU for the clinical field size and SSD, open-field PDD at the calculation point is 80%, and the physical-wedge factor at that point is 0.75. All remaining correction factors are 1.00. What monitor-unit setting gives field A its prescribed contribution?
Correct answer: C - 200 MU
A patient scheduled for palliative treatment of a rib metastasis mentions new mid-back pain that wakes him at night. Since yesterday, both legs have become weak and he has difficulty starting urination. He takes an opioid and has longstanding chemotherapy-related tingling in his toes. What should take priority before the rib treatment?
Correct answer: D - Hold treatment, assist with safe positioning, and obtain urgent assessment for spinal cord compression.
After complete macroscopic resection of a soft-tissue sarcoma, planning images show no residual mass. The radiation oncologist contours the operative bed and tissue at risk for microscopic extension. A separate geometric expansion is then added for delivery uncertainties. What is the first of these two volumes?
Correct answer: A - Clinical target volume (CTV)
Free-breathing and deep-inspiration breath-hold plans for left-breast tangential irradiation provide comparable breast coverage. The breath-hold plan exposes substantially less heart to the tangential fields. Which anatomic change most directly accounts for this benefit?
Correct answer: B - Lung expansion increases separation between the heart and anterior chest wall.
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