Question 1

In the conventional simulator, the _____________ represent(s)the radiation field.

Accepted Answer

The blades, also called the beam-restricting diaphragms, delineate the radiation field.

Question 2

Most computed tomography (CT)scanners today are _______-generation imaging systems.

Accepted Answer

In the third-generation scanners, the x-ray tube and detector array continue to rotate around the patient.

Question 3

Conventional simulators are designed to simulate the ____________, geometric, and optical properties of a variety of treatment units.

Accepted Answer

A benefit of a conventional simulator is that it can simulate the same conditions of treatment units, which include mechanical, geometrical, and optical properties.

Question 4

The CT number for dense bone is _________.

Accepted Answer

The CT values range from -1000 for air to 1000 for bone.

Question 5

The CT number for water is _____________.

Accepted Answer

The CT value for water is 0, which is the middle of the range of numbers.

Question 6

Where are positioning lasers located?
I.Side (lateral)
II.Overhead
III.Sagittal
IV.Coronal

Accepted Answer

The positioning lasers located on the side, overhead, and sagittal align at the isocenter.These lasers are used to mark the patient for setup in the treatment room.

Question 7

Which of the following represents the path of a photon when it enters the image intensifier?

Accepted Answer

The photons hit the input phosphor, which converts the x-rays to light.The light is then absorbed by the photocathode, which converts the light to electrons.The electrostatic lenses help the electrons focus to the anode.The output screen converts the electrons into an electrical signal that is transmitted to a screen.

Question 8

The matrix size is determined by the number of ___________.

Accepted Answer

The number of pixels determines the matrix size.The larger the number matrix, the better is the resolution.

Question 9

The central axis of the beam is ________________________.

Accepted Answer

The central axis of the beam always passes through the isocenter and is nondivergent.If asymmetric jaws are used, the central axis will not be the center of the field.

Question 10

___________ takes into consideration how much a machine will run in a normal week.

Accepted Answer

The workload is defined as the current (mA)multiplied by the time (minutes)a department expects to run the machine in the normal week.

Question 11

Which of the following details the difference in completing an axial scan as compared to spiral CT?

Accepted Answer

In a spiral CT scanner, the table moves during the scan, creating a helical pattern that looks like a Slinky.

Question 12

The patient couch tabletop is created out of this material, which has a low density and low x-ray absorption.

Accepted Answer

Tabletop manufacturers use carbon fiber for the table, which enables the radiation to pass through the table with minimal attenuation.

Question 13

Light photons are produced and transmitted electronically through to a video image at which of the following?

Accepted Answer

The light photons are converted from electrons at the output phosphor, which is then converted into an electronic image on a television screen.

Question 14

The Hounsfield unit for fat would be _________________.

Accepted Answer

The CT number or Hounsfield unit for fat is -100.

Question 15

__________ takes into consideration how an area on the other side of an irradiated wall is going to be used.

Accepted Answer

Occupancy factor will vary if the room adjacent to the simulator is a closet or has an employee there for 40 hours per week.

Question 16

As the field of view increases and the matrix size remains constant, the spatial resolution ____________.

Accepted Answer

As the field of view increases, each individual pixel increases in size, which results in less detail.

Question 17

The conventional simulator can define treatment fields by using which of the following?

Accepted Answer

The wires of the conventional simulator define the treatment field as delineated by the physician.The blades represent the radiation field.

Question 18

CT numbers are also known as which of the following?

Accepted Answer

A CT number is also called a Hounsfield unit after Sir Godfrey Hounsfield, who developed the first clinical CT scanner.

Question 19

A(n)_________ ring allows the CT x-ray tube to rotate in a continuous motion without the concern of cables becoming tangled.

Accepted Answer

The slip ring is similar to the metal on the ceiling of a bumper car ride.The power to the CT is conducted by the metal brushes on the ring.

Quiz 21: Simulator Design

In the conventional simulator, the _____________ represent(s) the radiation field.

Most computed tomography (CT) scanners today are _______-generation imaging systems.