Assignment 4 Flashcards
what are the most frequently seen CNS tumors?
mets to the brain
what percentage of all patients with cnacer have brain mets?
25%
what is the most frequent presenting symptom for metastatic brain cancer?
headache pain
what is papilledema?
Papilledema is a serious medical condition that occurs when there is a buildup of pressure in or around the brain, causing the optic nerve to swell. This causes visual disturbances, headaches, and nausea.
What percentage of parenchymal mets occur in the supratentorial compartment?
80%
What type of lung cancer is often treated prophylactically for brain mets?
Small cell or oat cell lung cancer
While simulating a whole/helmet brain, what are the 2 most important parts of mask making?
Forming the bridge of the nose & chin on the patient.
What can a Sim Tech do with patients who refuse a mask?
Take a chin to SSN measurement during Sim, then write that measurement in the patient’s setup notes so that Radiation Therapists take that same measurement for every treatment.
While simulating a whole/helmet brain, what device is used under the headrest?
shim
What radiation dose is considered palliative for whole/helmet brain treatment?
300 cGy/fx x 10 fx = 3000 cGy on 6MV
Why is flash used for whole/helmet brain treatment?
“The flash reduces the chances of clipping any of the anatomy as a result of the field size being too small”
What is the most critical structure in whole/helmet brain treatment?
Lenses of the eyes
What medication should be used to reduce edema in metastatic brain cancer patients? In what drug category is this medication?
- dexamethasone (i.e Decadron)
* corticosteroid
What are the field borders for a typical whole/helmet brain treatment?
Superior: 1.5 cm flash off the SKIN at the top of the head
Inferior: C2
Anterior: 1.5cm flash off the skin of the anterior frontal bone
Posterior: 1.5cm flash off the skin of the posterior occipital bone
Why is chemotherapy limited in the treatment of metastatic brain cancer?
Due to the inability of some chemotherapy drugs to cross the BBB (Blood Brain Barrier).
Excluding skin cancer, what is the most common head and neck cancer?
Laryngeal cancer / cancer of the larynx
The larynx is divided into 3 regions. List each.
Glottis, Supraglottis, & Subglottis
Laryngeal cancer occurs is which region of the larynx the most?
Glottis (65% of laryngeal cancers)
What is the most common histology of larynx cancer?
Squamous cell carcinoma
What are the classic presenting symptoms of larynx cancer?
A persistent sore throat and hoarseness
Describe patient positioning for simulating cancer of the larynx.
Supine, S Frame, C or Black HR w/ AccuForm Cushion, short mask, arms at sides holding jump ropes, knee sponge
When are wedges indicated in the treatment of larynx cancer?
To even out the dose (and avoid hot spots) by compensating for the contours of the neck.
What lymphatics are involved in vocal cord cancer?
None!
What is the most common site of distant metastases for laryngeal cancer?
The lungs
What is a poor prognostic indicator for laryngeal cancer?
Vocal cord immobility
Describe verrucous carcinoma of the larynx.
“Verrucous carcinoma is generally a well-differentiated, slow-growing, wart-like lesion that is relatively radioresistant. It has a tendency to convert to a highly anaplastic neoplasm after radiation therapy
