Final Exam - Treatment Procedures

Question 1

What is included in the scope of practice of a radiation therapist?

Answer 1

Pre-planning
Simulation
Dose planning
Administration of prescribed RT

Question 2

What items would you expect to see in a patient’s radiation oncology record

Answer 2

# of fractions
RX
Plan
Diagnosis/pathology test completed
medical history
immobilization
Patient set up
CA measurements
SSD's
schedules

Question 3

Examples of beam shaping device

Answer 3

MLCs and blocks

Question 4

Examples of beam modifying device

Answer 4

bolus
compensators
wedges
transmission filters

Question 5

What is the difference between beam shaping and beam modifying device?

Answer 5

• beam shaping modifys the “shape” in which the treatment field is delivered. It makes shapes that can more closely resemble the tumor shape in a specific field
• beam modifying devices alter how the dose is delivered to the body. This can cause the beam to change its dose distribution of level at which Dmax is reached inside the body

Question 6

What setup landmarks can be used?

Answer 6

Tattoos
surface anatomy
palpable bony protrustions
semi-permanent ink marks

Question 7

Define treatment field

Answer 7

• a field in which patients receive radiation and is shaped to the tumors characteristics
• patients can have multiple treatment fields
• field is outlined by the field light from the gantry head

Question 8

What is a common treatment technique for whole brain irradiation?

Answer 8

2 opposed rt. and lt lateral fields

Question 9

SRS

Answer 9

Stereotactic Radio Surgery

Question 10

IMRT

Answer 10

Intensity modulated radiation therapy

Question 11

SBRT

Answer 11

stereotactic body radiation therapy

Question 12

IGRT

Answer 12

image guided radiation therapy

Question 13

What can be used to manage a patient’s respiratory motion?

Answer 13

• using a vacuum seal positioning bag
• abdominal compression
• respiratory gating

Question 14

What are benefits of volumetric imaging?

Answer 14

• allows us to better see surrounding critical structures

- helps us to better account for movement in the patient and how the movement alters their treatment plan

Question 15

Define GTV, CTV, and PTV

Answer 15

GTV: Gross Tumor Volume
this is how much of the tumor is visible on scans

CTV: Clinical Tumor Volume
this is the GTV plus margins where additional cancerous cells could be

PTV: Planned treatment volume
this is CTV plus additional margins that account for possible movement during treatment delivery

Question 16

What perspective are treatment portals designed from?

Answer 16

Beam’s eye view

Question 17

Which is the smallest and largest treatment volume

Answer 17

largest –>PTV

smallest –>GTV

Question 18

What does IMRT help us better to achieve the goal of radiation therapy?

Answer 18

• Helps to increase dose to PTV
• helps to create tighter margins around the tumor due to MLC’s being used
• delivers non-uniform radiation to a treatment area. Uniform beams deliver radiation in a convex shape where as IMRT allows us to deliver radiation in concave fashion. allows us to give lower doses to surrounding critical structures
• bixels and control radiation to each bixel