Detection Equipment/Usage

Question 1

LINAC Commissioning Equipment

Answer 1

Water Scanner - 2 ion chambers

Question 2

LINAC X-Ray Calibration Equipment

Answer 2

Ion Chambers - farmer detector (.3cc to .6cc)

Question 3

LINAC e’ Calibration Equipment

Answer 3

Ion Chambers - Parallel Plate

Question 4

LINAC Flatness/Symmetry Equipment

Answer 4

Ion Chamber, Film

Question 5

LINAC Daly Output Equipment

Answer 5

Ion Chamber, Diode

Question 6

Pt dosimetry equipment

Answer 6

TLD’s, Diodes, OSL - positioning

Question 7

Personal Monitoring equipment

Answer 7

Film, TLDs

Question 8

Shielding survey leaks Equipment

Answer 8

GM Detector

Question 9

Shielding survey X-Ray Equipment

Answer 9

Ion Chamber

Question 10

Shielding survey Neutron Equipment

Answer 10

Proportion Counter - Rem-Ball or Activation Method

Question 11

Brachy Pt Survey Equipment

Answer 11

Ion Chamber

Question 12

Lost Seed Survey Equipment

Answer 12

GM Detector

Question 13

HDR/LDR Source Calibration Equipment

Answer 13

Ion Chamber - RE-entrant chamber

Question 14

Nuc Med Calibration Equipment

Answer 14

Ion Chamber

Question 15

Thyroid Uptake Equipment

Answer 15

Scintillation Detector - sodium iodide

Question 16

Nuc Med Camera Equipment

Answer 16

Scintillation Detector

Question 17

What is used to find leaks, lost sources, etc…, and measures beta and gamma

Answer 17

GM Detector

Question 18

What is used for pt surveys and shielding surveys, and measures beta and gamma

Answer 18

Handheld ion chamber

Question 19

Used for pt surveys and general surveys, and measures alpha, beta, and gamma

Answer 19

Cutie Pie Ion Chamber

Question 20

Used for contamination surveys

Answer 20

Alpha Probe

Question 21

Used for Neutron surveys

Answer 21

Rem Ball

Question 22

Used for LINAC Calibration, and measures photons and electrons

Answer 22

Farmer Chamber

Question 23

Used for LINAC Calibration of electrons

Answer 23

Parallel Plate Ion Chamber

Question 24

Used for HDR source calibration

Answer 24

RE-entrant Ion Chamber

Question 25

Used for contamination survey

Answer 25

Well detector (Nal)

Question 26

Used for thyroid bioassay (uptake)

Answer 26

Nal detector

Question 27

Used for pt dosimetry measurements

Answer 27

Diodes

Question 28

Used for IMRT QA

Answer 28

Detector Array (1000 diodes)

Question 29

Used for LINAC commissioning

Answer 29

Water Scanner

Question 30

How are gas filled detectors measured?

Answer 30

DC voltage (x-axis) x Voltage Pulse Height (signal)

Question 31

Name the sections and ranges of gas-filled detectors:

Answer 31

``` A: recombination - < 150 volts B: Ion chamber Region - 150 to 500 volts** C: Proportional Region** D: Geiger Muller Region** E: Continuous Discharge Region ```

Question 32

Describe the Ionization Region of gas-filled detectors:

Answer 32

1. voltage is sufficient to prevent recombination 2. Does NOT count individual event 3. Prevents Gas multiplication by - low V battery, and large collecting electrode 4. Used as survey meters, dose calibrators, and therapy chambers

Question 33

Describe the Proportional Region of gas-filled detectors:

Answer 33

1. Gas Multiplication 2. Detects individual events 3. Can distinguish between alpha and beta 4. Detects thermal neutrons 5. Used for LINAC shielding surveys (Rem Ball)

Question 34

Describe the Geiger Muller Region of gas-filled detectors:

Answer 34

1. Output pulse is constant regardless of E 2. Multiplication factor of 10^8 to 10^10 3. Unable to distinguish E 4. Detects individual events 5. Long Dead Time (300 usec) - cannot measure the radiation during this time 6. Saturation - may read background dose under high dose rate conditions 7. Used to detect presence of radiation (not dose measuring)

Question 35

Name the uses of Gafchromic Film:

Answer 35

1. Opthalmic Applicator dosimetry: Sr-90 2. Brachy Dosimetry 3. Stereotactic Radiosurgery Dosimetry 4. Dosimetry in the Penumbra Region 5. Intravascular Brachytherapy Dosimetry 6. Proton Dosimetry

Question 36

Gafchromic film depends on what?

Answer 36

1. Absorbed dose 2. Temp during irradiation 3. Post-Irradiation Reading Time - must wait at least 24hrs

Question 37

Name the advantages of TLD:

Answer 37

1. Range: mrad to 10^3 2 Dose Rate Independent 3. Small size and reusable

Question 38

Name the disadvantages of TLD:

Answer 38

1. Storage instability 2. Fading 3. Lack of Uniformity

Question 39

What are the uses of TLDs?

Answer 39

Personal Monitoring and Dosimetry Measurements

Question 40

For scintillation detectors, light is _____ to energy deposited?

Answer 40

proportional

Question 41

What are the advantages of a Scintillation Detector?

Answer 41

Efficient

Question 42

What are the disadvantages of a Scintillation Detector?

Answer 42

Fragile, hygroscopic, and expensive

Question 43

What are common uses for Scintillation Detectors?

Answer 43

Surveys for low E radiation, and for thyroid uptake studies

Question 44

Name 3 types of Point Detectors:

Answer 44

1. PP - electrons 2. diodes 3. Microchamber - really small volume

Question 45

What are the advantages of diodes?

Answer 45

1. small size 2. high sensitivity 3. instantaneous read-out 4. no bias voltage 5. simple

Question 46

What are the disadvantages of diodes?

Answer 46

1. cables 2. background signal: low dose rate problem 3. long-term calibration drift 4. variability of calibration with temp 5. can be unreadible 6. damage

Question 47

What are common uses of diodes?

Answer 47

1. Water tank dosimetry 2. TBI Doses 3. Electron measurements 4. Pt dose monitoring