18 Questions
What is the primary aim of treatment planning?
To deliver uniform dose to the target volume and minimize dose to surrounding tissues
What is the Gross Tumor Volume (GTV)?
The gross palpable, visible, and demonstrable extent and location of malignant growth
What is the Clinical Target Volume (CTV)?
The tissue volume that contains the GTV and subclinical microscopic disease
What is the Planning Target Volume (PTV)?
The CTV and includes margins for geometric or position uncertainties
What is the primary purpose of the Planning Target Volume (PTV)?
To allow for limitations in treatment technique
What is the Treated Volume?
The volume of tissue enclosed by an isodose surface, selected and specified by the radiation oncologists
What is the primary purpose of a conventional simulator in radiotherapy?
To localize the target volume and normal tissue
What is the purpose of the graduated scale or grid in the head of the conventional simulator gantry?
To broadcast an image of two perpendicularly crossed axes onto the patient's skin
What is the process of defining the treatment target and outlining organs in radiotherapy?
Target definition and outlining
What is the role of the X-axis in the XYZ coordinate system used for isocenter localization?
Extending right to left in the patient
What is the primary difference between a conventional simulator and a CT simulator in radiotherapy?
The use of virtual simulation
What is the purpose of radiographs taken during conventional simulation?
To document the gantry angles, field sizes, collimator angles, and table angles
What is the purpose of digitally reconstructed radiographs in the treatment planning process?
To visualize internal structures for tumor localization
Why is it important to position the patient in a reproducible manner during simulation?
To ensure accurate alignment of the radiation fields
What is the purpose of immobilization devices in simulation?
To maintain patient position during simulation
What is the primary function of field lights in patient alignment?
To align the radiation fields on the patient
What is the purpose of the protractor or gantry angle indicator?
To indicate the gantry angle during treatment
What is the role of lasers in patient alignment?
To provide a visual cue for patient positioning
Learn about the principles of radiation therapy treatment planning, including 3D rendering of patient outlines, target volume delineation, and minimizing dose to surrounding tissues. Understand the ICRU Reports 50/62 recommendations for target margins and more.
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