rad onc 3
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- Why must circumfrential radiation of STS be avoided?
- To avoid excessive fibrosis and edema
- With the use of a shrinking field technique the total dose for STS may exceed how many cGy?
- 7500
- Hodgkins lymphoma is characterized by the presence of what?
- Reed Sternberg cell
- Why does spleen involvement in HD indicate a poorer prognosis?
- Indicates late stage and increased risk bone marrow or liver involvement.
- For head and neck cancers with negative margins what is curative dose with radiation alone?
- 50 Gy
- For head and neck cancers what dose should positive nodes be irradiated for curative tx?
- 60 Gy
- What is the external radiation dose for gross disease in the floor of the mouth?
- 70 Gy, off cord at 45 Gy
- What is the boost dose to primary oropharyngeal tumors?
- 70 -75 Gy
- Describe the route of spread for cancer of the larynx.
- There are no capillary lymphatics so mets do not occur until tumor spreads beyond true vocal cords
- What is the external radiation dose for glottic lesions confined to the vocal cords?
- 66 Gy
- What is the dose to positive nodes in the neck region of the hypopharynx?
- At least 60 Gy
- What is the dose for gross disease of the hypopharynx?
- 70 Gy
- What is the initial dose to the lateral neck target volume for nasopharynx?
- 50.4 Gy
- What boost dose is given to nodal disease in nasopharynx?
- 65-75 Gy depending on staging
- What is the dose to the anterior neck in nasopharyngeal disease?
- 45-50 Gy
- Describe the route of spread for gliomas.
- Through local invasion along white matter tracts
- What is the conventional dose for partial brain fields?
- 60 Gy
- Describe the route of spread for pituitary tumors.
- Typically they are benign and cause damage by compression or local invasion.
- What is the conventional dose fractionation for pituitary tumors?
- 45-50 Gy
- What dose is needed to eliminate gross HD?
- 36-44 Gy
- What is the survival prognosis for lung caner?
- 10% in 5 yrs
- Describe the conventional dose fractionation used in cancer of the esophagus.
- 30-50 Gy for palliation
- Describe the conventional radiation therapy fractionation for superior vena cava syndrome.
- 3-4 Gy for 2-3 days followed by conventional fx
- what are the two most common malignancies causing SVCS?
- Lung caner and lymphomas
- Describe the treatment portal for SVCS?
- Primary tumor with 2-3 cm margins plus mediastinal, hilar, and superclavicular areas
- Describe the treatment portal for spinal cord compression.
- Single post port with 3-4 cm margins above and below lesion
- Describe the dose to tumor for spinal compression.
- 30 - 40 Gy in 2 weeks, beginning with higher fractionation for 3-4 tx
- What is the conventional dose for pre-op STS?
- 50 Gy
- What is the conventional dose for post-op STS?
- 65 Gy total dose with field reduction at 45-50
- What is the most common STS in children?
- Rhabdomyosarcoma
- What is the long term prognosis for children with rhabdomyosarcoma?
- 2/3 survivors
- What is the conventional CNS radiation dose?
- 24 Gy/12/2 to whole brain and 12/6/2 to spine with concurrent chemo
- The whole abdomen is treated to this dose for ovarian cancer.
- 25-30 Gy at 1.5/fx
- Describe dose fractionation for cancer of the rectum.
- 45 Gy conv fx, up to 50 Gy advanced disease
- Primary lymphatic drainage of lower lip
- submental nodes
- Most common primary head and neck tumor
- squamous cell