(a) Shielding blocks are most commonly made of: (i) gold (ii) tin (iii) iron (iv) lead (b) Tenth value layer will reduce the primary intensity by: (i) 50% (ii) 10% (iii) 20% (iv) n... (a) Shielding blocks are most commonly made of: (i) gold (ii) tin (iii) iron (iv) lead (b) Tenth value layer will reduce the primary intensity by: (i) 50% (ii) 10% (iii) 20% (iv) none of these (c) The melting point of cerrobend block is: (i) 327°C (ii) 70°C (iii) 270°C (iv) none of these (d) Asymmetric collimation changes: (i) transmission pernumbra (ii) geometric penumbra (iii) physical penumbra (iv) none of these (e) The interleaf transmission of MLC is usually less than: (i) 3% (ii) 2.5% (iii) 5% (iv) none of these (f) Electron contamination of photon beam: (i) increases skin sparing effect (ii) decreases skin sparing effect (iii) keep same the skin sparing effect (iv) none of these (g) Head and Neck cancer RT treatment spine shield after: (i) 50Gy (ii) 44Gy (iii) 56Gy (iv) 60Gy (h) Wedge field used in treatment of: (i) Ca-Tonsil (ii) Ca-tounge (iii) Ca-Maxilla (iv) Ca-Breast
Understand the Problem
The image presents a series of multiple-choice questions related to radiation therapy and medical physics. The questions cover topics such as shielding materials, radiation intensity reduction, cerrobend block melting points, collimation, MLC transmission, electron contamination, and treatment techniques.
Answer
(a) lead, (b) 10%, (c) 70°C, (d) geometric penumbra, (e) 3%, (f) decreases skin sparing effect, (g) 44Gy, (h) Ca-Breast
Here are the answers to the multiple-choice questions:
(a) Shielding blocks are most commonly made of: (iv) lead (b) Tenth value layer will reduce the primary intensity by: (ii) 10% (c) The melting point of cerrobend block is: (ii) 70°C (d) Asymmetric collimation changes: (ii) geometric penumbra (e) The interleaf transmission of MLC is usually less than: (i) 3% (f) Electron contamination of photon beam: (ii) decreases skin sparing effect (g) Head and Neck cancer RT treatment spine shield after: (ii) 44Gy (h) Wedge field used in treatment of: (iv) Ca-Breast
Answer for screen readers
Here are the answers to the multiple-choice questions:
(a) Shielding blocks are most commonly made of: (iv) lead (b) Tenth value layer will reduce the primary intensity by: (ii) 10% (c) The melting point of cerrobend block is: (ii) 70°C (d) Asymmetric collimation changes: (ii) geometric penumbra (e) The interleaf transmission of MLC is usually less than: (i) 3% (f) Electron contamination of photon beam: (ii) decreases skin sparing effect (g) Head and Neck cancer RT treatment spine shield after: (ii) 44Gy (h) Wedge field used in treatment of: (iv) Ca-Breast
More Information
The tenth value layer (TVL) is the thickness of material required to attenuate the beam intensity to 1/10th of its original value, thus reducing the primary intensity by 10%. Cerrobend is an alloy commonly used for radiation shielding due to its low melting point.
Tips
Some of the terms are very similar, so read each answer carefully.
Sources
- Treatment Planning III: Field Shaping, Skin Dose, and Field Separation - radiologykey.com
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