Assignment 4

Question 1

what are the most frequently seen CNS tumors?

Answer 1

mets to the brain

Question 2

what percentage of all patients with cnacer have brain mets?

Answer 2

25%

Question 3

what is the most frequent presenting symptom for metastatic brain cancer?

Answer 3

headache pain

Question 4

what is papilledema?

Answer 4

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.

Question 5

What percentage of parenchymal mets occur in the supratentorial compartment?

Answer 5

80%

Question 6

What type of lung cancer is often treated prophylactically for brain mets?

Answer 6

Small cell or oat cell lung cancer

Question 7

While simulating a whole/helmet brain, what are the 2 most important parts of mask making?

Answer 7

Forming the bridge of the nose & chin on the patient.

Question 8

What can a Sim Tech do with patients who refuse a mask?

Answer 8

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.

Question 9

While simulating a whole/helmet brain, what device is used under the headrest?

Answer 9

shim

Question 10

What radiation dose is considered palliative for whole/helmet brain treatment?

Answer 10

300 cGy/fx x 10 fx = 3000 cGy on 6MV

Question 11

Why is flash used for whole/helmet brain treatment?

Answer 11

“The flash reduces the chances of clipping any of the anatomy as a result of the field size being too small”

Question 12

What is the most critical structure in whole/helmet brain treatment?

Answer 12

Lenses of the eyes

Question 13

What medication should be used to reduce edema in metastatic brain cancer patients? In what drug category is this medication?

Answer 13

• dexamethasone (i.e Decadron)

* corticosteroid

Question 14

What are the field borders for a typical whole/helmet brain treatment?

Answer 14

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

Question 15

Why is chemotherapy limited in the treatment of metastatic brain cancer?

Answer 15

Due to the inability of some chemotherapy drugs to cross the BBB (Blood Brain Barrier).

Question 16

Excluding skin cancer, what is the most common head and neck cancer?

Answer 16

Laryngeal cancer / cancer of the larynx

Question 17

The larynx is divided into 3 regions. List each.

Answer 17

Glottis, Supraglottis, & Subglottis

Question 18

Laryngeal cancer occurs is which region of the larynx the most?

Answer 18

Glottis (65% of laryngeal cancers)

Question 19

What is the most common histology of larynx cancer?

Answer 19

Squamous cell carcinoma

Question 20

What are the classic presenting symptoms of larynx cancer?

Answer 20

A persistent sore throat and hoarseness

Question 21

Describe patient positioning for simulating cancer of the larynx.

Answer 21

Supine, S Frame, C or Black HR w/ AccuForm Cushion, short mask, arms at sides holding jump ropes, knee sponge

Question 22

When are wedges indicated in the treatment of larynx cancer?

Answer 22

To even out the dose (and avoid hot spots) by compensating for the contours of the neck.

Question 23

What lymphatics are involved in vocal cord cancer?

Answer 23

None!

Question 24

What is the most common site of distant metastases for laryngeal cancer?

Answer 24

The lungs

Question 25

What is a poor prognostic indicator for laryngeal cancer?

Answer 25

Vocal cord immobility

Question 26

Describe verrucous carcinoma of the larynx.

Answer 26

“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