MDCb

MDCB EXAM QUESTIONS AND ANSWERS. A+ GRADED GUIDE. In TG 43, what variable is known as F? Anisotropy: provides dose falloff info using attenuation and scatter only perpendicular to the radial dose function This would be the "along" portion on the along and away tables, rotation away from central axis Steps done to complete a survey of an HDR brachytherapy procedure using an ion chamber survey meter? 1st. Before treatment survey of afterloader to confirm source is contained 2nd. Ac...

MDCB EXAM QUESTIONS AND ANSWERS. A+ GRADED GUIDE. Rule of thumb for proton attenuation? Protons will lose about 10 MeV per cm Typical treatment energy range for protons? From 80 MeV to 250 MeV What are the three dominant photon interactions in radiation oncology? Photoelectric Effect, Compton Scattering (incoherent scattering), and Pair Production What determines the energy of a released electron during the photoelectric effect? Energy of electron = energy of incoming photon - binding en...

MDCB EXAM QUESTIONS AND ANSWERS. A+ GRADED GUIDE. What is a half-life? Time it takes for a particular quantity (activity) to reduce to 50% What is the decay constant (lambda) formula? lambda = ln(2) / half-life What is the mean life formula? mean life = 1.44 (half-life) What is the formula for radioactive decay? A=A0 e^(-λt) Half-life of Pd-103? 17 days Half-life of I-125? 59.4 days Half-life of Ir-192? 73.8 days Half-life of Cs-137? 30.2 years Half-life of Co-60? 5.26 years ...

MDCB EXAM QUESTIONS AND ANSWERS. A+ GRADED GUIDE. The energy equivalent of an atomic mass unit is: (A) 0.5 MeV. (B) 1.0 MeV. (C) 931.0 MeV. (D) 1000.0 keV. (C) 931.0 MeV. Which of the following describe(s) the Becquerel (Bq)? (A) 3.7 x 108 mCi (B) 3.7 x 1010 mCi (C) 2.7 x 10-8mCi (D) 2.7 x 10-10mCi (C) 2.7 x 10-8mCi The best way to reduce dose to a patient's right optic nerve while treating a right lacrimal gland tumor with non-coplanar 6 MV photons is to instruct the patient to:...

MDCB EXAM QUESTIONS AND ANSWERS. A+ GRADED GUIDE. The measured and computer generated isodose curves should agree within: A. +/- 3%, 2mm. B. +/- 2%, 3mm. C. +/- 2%, 2mm. D. +/- 3%, 3mm. C. +/- 2%, 2mm. Dose variation across the field at a specified depth is referred to as: A. medial alignment B. dose profile C. beam profile D. lateral alignment C. beam profile An Ir-192 HDR source is being utilized in conjunction with a breast balloon for a breast treatment. What would be the typica...

MDCB EXAM QUESTIONS AND ANSWERS. A+ GRADED GUIDE. According to QUANTEC guidelines, in order to avoid a 5% risk of dysfuntion, less than 55% of the volume of Kidneys should receive what dose? A. 6 Gy B. 12 Gy C. 24 Gy D. 32 Gy B. 12 Gy According to QUANTEC guidelines, what rate of spinal cord myelopathy would be expected if 70 Gy were delivered to the spinal cord with conventional fractionation of 2 Gy per day? A. < 5% B. 20% C. 50% D. 100% C. 50% A radiation oncologist is designi...

MDCB EXAM QUESTIONS AND ANSWERS. A+ GRADED GUIDE. The minimum nominal distance a tissue compensator should be placed from the skin surface without affecting the skin sparing effect is: A. 5.0 cm. B. 10.0 cm. C. 20.0 cm. D. 25.0 cm. C. 20.0 cm. The radiation therapy technique which utilizes many shaped beams which may NOT conform to the target volume to achieve a highly conformal distribution is: A. conventional forward treatment planning. B. intensity modulated radiation therapy (IMRT)....

MDCB EXAM QUESTIONS AND ANSWERS. A+ GRADED GUIDE. Although they receive the same dose, some tissues exhibit acute radiation damage earlier than others because they have a: A. smaller number of metabolizing cells. B. reduced blood flow. C. lower number of hypoxic cells. D. higher mitotic index. D. higher mitotic index. Unless otherwise permitted by the NRC, brachytherapy needles and tubes must be leak tested by the user at intervals NOT to exceed: A. 1 month. B. 3 months. C. 6 months. ...

MDCB EXAM QUESTIONS AND ANSWERS. A+ GRADED GUIDE. Extra consideration of immobilization for SBRT patients is needed due to: A. rapid dose falloff. B. length of treatment time. C. multiple beams. D. increased imaging time. A. rapid dose falloff. What lead thickness is required to reduce the transmission to less than 5 percent for a 12.5 x 12.5 cm2, with a 12 MeV electron field? A. 1.2 mm B. 3.0 mm C. 5.6 mm D. 8.0 mm C. 5.6 mm Brachytherapy cervix applicators are often made of titani...

MDCB EXAM QUESTIONS AND ANSWERS. A+ GRADED GUIDE. What factors are instrumental in determining the dose uniformity in equally weighted parallel opposed beams? A. beam energy, tissue inhomogeneity and patient thickness B. beam energy, patient thickness and tissue maximum ratio C. beam flatness, patient thickness and collimator scatter D. patient thickness, inhomogeneity and collimator scatter A. beam energy, tissue inhomogeneity and patient thickness Two adjacent electron fields are to be ...