Xray Basic Test

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1

99% of an incoming electron's energy is transferred as

Heat

2

1% of an incoming electron's energy is transferred as

X-rays

3

The broad spectrum of x-ray energy (slowed)

Brems

4

The narrow spectrum of X-ray energy (peaks), which are specific to target electrode material

Characteristic

5

Passes through the filament and heats it

Current

6

Produces a cloud of free electrons dependent on temperature

Heated filament of the cathode

7

Electrons are attracted and accelerated towards

Target anode

8

Electrons that hang around the filament, causing lower kV and requiring more filament heating

Space charge

9

Units of heat for measuring x-ray tubes

Joules and HU's

10

Joule equals

watt per second

11

HU equals

(kV x mA x seconds) x 1.4

12

(80 x 200 x .15) x 1.4 equals

3360 HU

13

80 x 200 x .15 equals

2400 J

14

Two major effects of anode material on x-ray spectrum

Efficiency of production, presence of characteristic radiations and their energy.

15

Characteristic peaks of Tungsten (W)

10kV

16

Used for low-energy radiation (17kV or 20 kV) for soft tissue, specifically mammography

Molybdenum (Mo) and Rhodium (Rh)

17

As kV increases, photon energy

Increases

18

kV has a significant effect on

Relative amplitude of characteristic radiation

19

Has better penetration and used for dense or thick parts of the body

High-energy (60-120kV)

20

Used for soft tissue

Low-energy (20-40 kV)

21

mA controls_____________but does not change it's energy

Intensity of the beam

22

In an x-ray image, darker parts indicate

Little absorption and low density tissue

23

In an x-ray image, lighter parts indicate

High absorption and high density tissue

24

kV mainly affects image...

Contrast

25

mA mainly affects image

Brightness

26

Intensity of a beam at a given point in space, used to express output exposure of an x-ray device.

Roentgen

27

Tube current multiplied by time in seconds

mAs

28

Electrical charge produced in a unit mass of air

Quantity of ionization

29

Intensity of an x-ray beam is inversely proportional to the square of the distance from the x-ray source

Inverse square law

30

Inverse square law

Dose at distance 2=(Distance 1/Distance 2) x Dose at distance 1

31

Quantity of energy absorbed, per kilogram, in a unit of mass of material

RAD (Radiation Absorbed Dose)

32

Absorbed dose equivalent, regarding biological effects depending of type of ionizing radiation

REM (Radiation Equivalent Man)

33

1 REM equals

1 RAD

34

Absorbed dose measured at the skin level

Surface Dose

35

Another name for surface dose

Entrance dose

36

1 Gray equals

1 J/Kg

37

1 Sievert equals

100 REM

38

1 cGy (centigray) equals

1 Rad

39

115 Roentgen equals

1 Gray

40

Assemblies of the X-ray generator

PDU, step-up transformer, operator console, exposure control circuit

41

Functions of the x-ray generator

Control kV to tube (penetration), mA (quantity), exposure time, and switching

42

Types of generators

Single phase, 3 phase, HF

43

Full-wave rectified tube with maximum ripple

Single phase generator

44

More uniform kV output, less ripple, classified as 6 pulse or 12 pulse

Three phase generator

45

Uses a "wye" step-up transformer to reduce ripple to 13%

Six pulse generator

46

Uses "wye-delta" step up transformer to reduce ripple and reduce patient exposure to harmful radiation

12 pulse generator

47

AC converted to DC and applied to inverter/chopper to produce virtually no ripple, then converts back to AC at 20kHz and higher.

HF generator

48

The smallest generator type

High Frequency

49

Bucky provides housing for these assemblies

Cassette tray, grid

50

Two purposes of the cassette tray

Hold and center

51

Where is the cassette tray located?

Track below tabletop

52

A series of lead foil strips separated by x-ray transparent spacers.

Grid

53

Function of a grid.

Improve contrast by blocking secondary radiation.

54

Difference between height of the lead strips and distance between them, usually expressed as two numbers 4:1, 16:1, etc.

Grid ratio

55

As grid ratio increases, grid function becomes

Better

56

Material that is relatively transparent to x-ray

Aluminum

57

Part of grid that removes scatter

Lead strips

58

May cast a pattern of strips onto the xray image that appear as a series of fine, parallel, unexposed lines.

Stationary grid

59

Eliminates grid lines by blurring the grid line images, removing scatter, and having no effect on primary beam transmission

Moving grid

60

Usually moves transversely in a simple front to back oscillation

Bucky

61

Two types include focused or parallel lead strips

Grid patterns

62

Lead strips are angled

Focused grid

63

Distance from the grid to the point of intersection

Focal distance

64

Lead strips are not angled

Parallel grid

65

In a parallel grid, uniform density is limited to this

Width of about 10 cm

66

What is an advantage of a parallel grid

Long focal distance

67

Higher grid ratio

More scatter radiation absorbed

68

Lower grid ratio

Less contrast in image

69

Higher grid ratio

Higher radiation exposure to patient

70

Lower grid ratio

Less necessity to accurately position grid under tube

71

Most frequent grid ratios

8:1-12:1

72

Frequency of the grid

Fineness

73

The number of lead strips (lines) per cm

Frequency

74

Lower grid frequency usually results in

Move visible lines and thicker grid line material

75

The result of poor alignment between primary x-ray beam and lead strips of grid

Grid cutoff

76

Appearance of grid cutoff in image

Lightness

77

Results in progressively decreased density toward edges of film from shadows proportionate to distance from central beam

Parallel Grid Cutoff

78

Common cause of parallel grid cutoff

Tube too close to grid

79

Happens when tube is outside of a specified range

Focused grid cutoff

80

Results in severe cutoff on edges of film and dark band of exposure in the center, usually caused by inserting a grid upside down

Inverted focused grid cutoff

81

Uniform loss of radiation over entire surface of grid

Off-center cutoff

82

Most common type of grid cutoff, usually attributed to incorrect exposure settings, and can be minimized by low ratio grids and long focal distances.

Off-center cutoff

83

Xray beam restrictor

Collimator

84

Collimator controls

Dimensions of x-ray beam

85

Collimator aligns

X-ray beam, patient, and bucky prior to exposure

86

Collimator limits

patient and technician exposure to radiation

87

Collimator reduces

Scatter radiation

88

Thin metal sheets that attenuate low energy radiation and reduce absorbed patient dose

Spectral filters

89

X-ray beam control uses these to control beam dimensions

Shutters

90

Simulates the position of the central beam and allows technologist to pre-center

Collimator light

91

Used to alight image receptor to collimator

Bucky alignment light

92

Detent button controls this alignment

Transverse

93

This alignment must often be done manually

Longitudinal

94

Posiiton alignment light on center of

Bucky handle

95

Controls the shutter blades to adjust automatically to the size of the film cassette

Automatic collimation

96

Cassette size information is sent to

Collimator motor control circuits

97

For small areas, can collimator blades be manually adjusted smaller than film cassette?

Yes

98
card image

Basic collimator control circuit

99

Made of several metals and used to evaluate image quality and contrast

Cardio Vascular Phantom

100

Cylinder with pin hole in base and leaded glass output phosphore

Collimator Alignment Tool

101

Made of lead converging lines shown in pairs per mm and used to evaluate image chain resolution or focus

Funk Phantom

102

Another name for Funk Phantom

Line Pair

103

Used to display voltage signals as waveform

Oscilloscope

104

Used to measure actual x-ray tube beam current (mA) and plugged into connectors at generator high voltage tank (after removing jumper connecting the two terminals

mA meter

105

Used to measure kV by plugging into kV packs and connecting to o-scope

Keithley kV meter

106

Used to measure kV by placing directly in the beam and performing exposure

RMI kV meter

107

Used to measure dose or dose-rate

Rad dose meter

108

Consists of kV meters, mAs meter, base unit, and dose chambers

Keithley Triad

109

Used to compare light intensity on one side of a piece of processed film with the light intensity emerging from the other side.

Densitometer

110

Safety equipment that must always be worn in the lab

Safety shoes

111

Must be worn in fluoro rooms with x-ray on

Lead apron

112

Stand behind this to protect from x-ray

Lead screen

113

Use these when turning main breaker on or off or connecting a DVM to a live circuit.

Safety glasses

114

Any devices, such as a fluorescent screen, radiographic film, x-ray image intensifier tube, solid-state detector, or gaseous detector, which transforms incident x-ray photons into a visible image or form which can produce a visible image

Image Receptor

115

Analog image receiver

Film

116

Types of digital receivers

Indirect and direct

117

A type of indirect digital image receiver

Computed Rad

118

A latent image is captured onto a transporting media and then read into digital format

Computed rad

119

Types of digital image receivers that use indirect xray detection

Amorphous silicon, charge-coupled device, closed-circuit TV tube.

120

Types of digital image receivers that use direct xray detection

Complementary metal-oxide semi-conductor, gas-filled ionization chamber detector, amorphous selenium

121

A photo-conductor that directly converts XR to signal

Amorphous selenium

122

The most common radiographic recording device

Film

123

Characteristics of film

Sensitive to light, low sensitivity to x-ray

124

Percentage of x-rays absorbed by film

2-3

125

An acceptable way to produce an acceptable x-ray image on film

Convert to light rays

126

Developed to reduce patient exposure to x-rays using scintillation effect to convert x-rays to visible light.

Fluorescent intensifying screens

127

Another name for FIS

Intensifying screen

128

A high energy photon is converted to many low energy photons (visible light)

Scintillation effect

129

Scintillation materials

Phosphor, cesium iodide, selenium

130

Where are intensifying screens mounted

Inside a padded cassette

131

When placing an intensifier screen in cassette, pay attention to these things

Proper contact, film sensitivity matches light frequency

132

Top layer of intensifying screen

External protective coating

133

Second layer from top of intensifying screen

Bonded phosphor crystals

134

Second layer from bottom of intensifying screen

Thin layer of reflecting material

135

Bottom layer of intensifying screen

Plastic base support

136

Materials used to make phosphor layer

Calcium Tungstate and rare earth

137

Emits blue light photons

Calcium tungstate

138

Emits green light photons

Rare earth

139

When using intensifying screens, X-ray film images are produced primarily by

Visible light from the intensifying screen

140

The ability of fluorescent material to convert x-ray photons to light photons

Intrinsic efficiency

141

Intrinsic efficiency of calcium tungstate

5 percent

142

Intrinsic efficiency of rare earth

20 percent

143

The ability of light created by intensifying screen to reach the film (typically about 50% of light photons produced reach the film)

Screen efficiency

144

As kV increase, amount of light from the screen

increases

145

As kV decreases, amount of light from the screen

decreases

146

This is determined by the thickness of the flourescent phosphor layer

Speed of an intensifying screen

147

Has a relatively thick phosphor layer

Fast screen

148

Has a relatively thin phosphor layer

Slow screen

149

Fast screens have

Increased image brightness

150

Slow screens have

Increased image resolution

151

Fast screens reduce image blurring by having

Shorter exposures

152

Slow screens increase patient dose due to

Longer exposures

153

Characteristics of film

Stiff, dimensional stability, low water absorbsion

154

How many layers are in double sided film

7

155

The outermost layer of film

T coat

156

Second outermost layer of film

Emulsion

157

Third outermost layer of film

Adhesive

158

Innermost layer of film

Base

159

Roughly how thick is modern film

0.2 mm

160

What color is film

Clear or blue tint

161

The active layer of film that absorbs radiation (x-ray or light) and records the latent image

Emulsion

162

Consists of microscopic crystals of silver halide suspended in gelatin

Emulsion layer

163

Hard protective coating of film

T coat

164

What is located between intensifying screens in a cassette

Film

165

This is created on film emulsion by exposure to either ionizing radiation or light

Latent image

166

Another name for latent image

Radiographic image

167

Acts on silver halide to create an image

Photons

168

These are used to make the invisible film image visible

Processing chemicals

169

This processing stage amplifies the latent image by a factor of hundreds of millions to form a visible metallic silver (black) image

Developing

170

How many film processing stages are there

4

171

This film processing stage removes unexposed silver halide crystals and hardens the gelatin, preventing the image from fading over time

Fixing

172

This film processing stage removes all chemicals and prevents discoloration

Washing

173

This film processing stage allows the film to be handled

Drying

174

How many major characteristics does film have

4

175

Measures the blackening of a film

Density

176

The ability to display a range of densities from white to gray to black

Contrast

177

The ability to respond to light or ionizing radiation

Speed or sensitivity

178

Range of relative exposures that will produce density within the accepted range for diagnostic radiology.

Latitude

179

A heavier deposit of silver produces

Greater absorption of light and darker area

180

Blackness

Density

181

Range of useful densities on a radiograph

0.25 to 2.5

182

Higher density equals

More darkness on film

183

Density of 2 is how many times darker than density of 1

10

184

Compares light intensity on one side of processed film with light intensity on other side

Densitometer

185

Densitometer's digital output range

0.0-3.6

186

Used to make a carefully controlled series of exposures on a strip of film

Sensitometer

187

The parts of an H-D curve

Toe, Shoulder, Intermediate density region

188

Region below the straight line of the characteristic curve (low density)

Toe

189

Region above the straight line of the characteristic curve (high density)

Shoulder

190

Nearly vertical, straight line portion of characteristic curve (area of maximum contrast)

Intermediate density region

191

Ideally, radiographic exposures fall within this section of the H-D curve

Intermediate density region

192

Density of the film without exposure to radiation (result of dye added to most film during manufacturing).

Base density

193

The purpose of dye in film

Relieve eyestrain

194

Undesirable effect caused by film age, background radiation, chemical vapors, or warm temperatures

Fogging of fog density

195

Used to prevent fogging

Passboxes

196

Affected by film type, processing conditions, density level, fog level

Film contrast

197

Steepness of characteristic curve

Slope

198

Uses re-usable image plates

Computed radiology (CR)

199

Used to scan plates and send image data to workstation

Digitizer

200

Processes and reviews images

Workstation

201

Where released images are sent to

PACS

202

Used to identify cassette

ID Tablet or Bar code system

203

Digitizer uses this to scan image and release as visible light

Laser beam

204

Increases contrast and other features for better quality

Post processing

205

Minimizes errors in x-ray technique by allowing technologist to select kV and mA and determining exposure time

Automatic Exposure Control (AEC)

206

Advantages of AEC

Limit patient exposure, reduce operator mistakes and re-takes of exam.

207

When is AEC usually calibrated

At time of installation

208

Senses radiation and produces a proportional electrical signal

Detector circuit

209

Types of detector circuits

Ionization chamber, photomultiplier tube, silicon cell (solid state, digital)

210

Adds output from the detector

Integrator

211

Compares integrator output to a voltage reference that equals desired film density

Comparator

212

Signal created when input voltage equals reference voltage

Exposure stop

213

Where is exposure stop signal fed to

Generator

214

Compensates for variations in kV, time, and cassette size

Reference voltage

215

Located above x-ray film for AEC

Entrance detector

216

Located below x-ray film for AEC

Exit detector

217

Converts transmitted radiation to an electrical signal and under the grid in the bucky assembly in table or chest stand.

Ion chamber

218

Wall stand ion chamber contains how many sensing areas

3

219

The sensing area in center of wall stand

2

220

The sensing areas in corner of wall stand

1 and 3

221

Detector typical used in mammography and centered underneath the breast

Photomultiplier tube (PMT)

222

Parts of a CR system

Digitizer, processing computer, ID tablet, cassettes

223

Digitizer uses this to communicate with processing pc

ethernet

224

ID tablet connects to processing computer using this

USB link

225

On Agfa CR, LGM value should be between

2.1 and 2.3

226

The primary x-ray beam, leaving the tube target surface at 90 degrees, but does not necessarily pass through the point of maximum beam intensity.

Central ray

227

Used in radiographic applications to align the x-ray system with anatomical area of interest

Central ray

228

Where electron beam from tube filament lands on the angled target surface

Actual focal spot

229

What shape is the actual focal spot bombarded by a stream of electrons

Rectangular

230

Area from where the x-ray beam appears to come from

Effective focal spot

231

From central ray perspective, what shape is the effective focal area

Square

232

Which spot is commonly called the focal spot

Effective focal spot

233

Determined by length of tube filament, diameter of filament wire coil, width and length of focusing cup slot, and depth of focusing cup

Size and shape of actual focal spot

234

Determined by viewing the target at a 90 degree angle from the anode target

Effective focal spot size

235

Used to measure focal spot size, especially in mammo and cardio systems

Star pattern

236

Positioned about midway between the focal spot and the film, parallel to film, in central ray of the beam.

Star pattern

237

Tool used for measuring focal spot size that produces image of focal spot on a piece of film

Pin-hole camera

238

Set at an angle to bend x-rays to output port

Target

239

Another name for output port

Window

240

As target angle increases, effective focal spot size

Increases

241

As target angle increases, maximum loading must be ___________ to prevent creating a melt spot on the target

Decreased

242

As target angle decreases, it can absorb _____________ heat

More

243

As target angle decreases, maximum kilowatt rating can be

Increased

244

The distribution of x-ray beam intensity is greatest at the side of the target closest to filament

Heel effect

245

Detectable variation in film density due to variation in beam intensity

Cut-off

246

What side of the target should thickest section of patient be positioned

Cathode side

247

Out of focus shadow around outer edge

Penumbra

248

Effect of penumbra that distinguishes it from other causes

Geometric unsharpness

249

(X1 + X2)/SID x 100=

X-ray to light field error.

250

Used for imaging a selected plane, or layer of anatomy

Tomography

251

Maintains the same position on the film during tomography

Fulcrum

252

Thickness of tomographic slice depends on

Length of tube travel

253

Wide angles of tube movement (>10 degrees) produce

Thin sections

254

Narrow angles of tube movement (<10 degrees) produce

Thick sections

255

Lower contrast used for bone

Wide angle tomography

256

Higher contrast used for soft tissue

Narrow angle tomography

257

Tomographic methods

Arc-line, rectilinear (line-line), curvilinear (arc-arc)

258

Tube moves in arc, while bucky moves in straight line in opposite direction

Arc-line

259

Characteristics of arc-line

SID constant, ratio of source-object distance varies, magnification varies, edge-edge image sharpness varies

260

Tube and bucky move in straight line in opposite directions

Rectilinear

261

Characteristics of rectilinear

SID varies, source object ratio remains constant, magnification constant, edge-edge sharpness constant

262

Tube and bucky move in opposite directions through an arc

Curvilinear

263

Characteristics of curvilinear

SID, source-object ratio, magnification, and edge-edge sharpness all constant

264

Another name for curvilinear method that is basis for CT

Grossman principle

265

Types of GE digital detectors

Tethered (TRAD) and fixed

266

Uses an external chiller to keep the detector temp constant

Fixed detector

267

Advantages of digital detectors

Replaces film, image intensifiers, need for dark room, processor, chemicals, storage.

268

Compared to CR and film, digital provides

Better image quality at lower dose and advances processing algorithms.

269

Absorbs x-ray photons in digital detector and converts them to light

Cesium iodide scintillator

270

In digital detector, absorbs light and converts it into an electronic charge, each representing a pixel or picture element

Amorphous Silicon Panel Photodiode array

271

Interprets charge at each pixel and converts to digital data that is sent to an image processor

Read out electronics

272

The process of making permanent photographic records of anatomy through which an ionizing beam of radiation has passed

Radiography

273

Well adapted to image high contrast, slow, or non-moving objects

Radiography characteristic

274

Includes skull, spine, pelvis, extremitites

Bony skeleton

275

Lungs, abdomen, urinary tract

Soft tissues

276

Objects such as coins, utensils, light bulbs

Foreign bodies

277

First radiographic procedure

Physician referral

278

After physician referral is this radiographic procedure step

Exam request

279

The third radiographic procedure

Exam

280

Following a radiographic exam, this step takes place

Reading

281

The final step in a radiographic procedure

Report

282

An example of a service provider

Radiology department

283

How many primary components in an Xray system

Six

284

Used to operate the x-ray system

Hand switch

285

What are the positions of the hand switch

Prep and expose

286

This happens during the prep stage

Signal and power go from x-ray controller to tube filament power supply to tube filament. Filament warms up and rotor is powered up to speed.

287

What happens when cassette is placed in bucky tray

Collimator will adjust to match film

288

This happens during exposure stage

X-ray controller sends signal to power unit, HV transformer boosts current and voltage, tube emits, radiation detector sends signal to AEC.

289

Who discovered X-rays

Wilhelm Conrad Roentgen

290

When were x-rays discovered

November 8, 1895

291

The "x" in x-rays represents

An unknown

292

After announcement of x-ray discovery, when did GE produce their first x-ray system?

A few months later.

293

Who demonstrated the first use of x-rays for diagnosis of fractures and location of foreign objects within the human body?

Elihu Thomson

294

Who started the first school of radiography

Eddy C. Jerman

295

Invented hot-filament cathode tube (thermonic emission tube) in 1913

William David Coolidge

296

Purchased Victor X-ray corporation in 1926

General Electric

297

What year were the first rotating anode tubes

1937

298

GE entered this field in 1957 with use of an image intensifier

Flouroscopy

299

What year did GE develop the first digital detectors

1990

300

When an electron is submitted to an electrical field, it is accelerated ______________ to the applied voltage

Proportional

301

The expression of an electron's speed

Electron Volt (eV)

302

Kinetic energy when an electron reaches positive electrode

1 KeV

303

Unit of energy measurement of photons

Electron volt

304

In the electromagnetic spectrum, what wavelength range are x-rays

Short

305

Measurement of wavelength

Angstroms

306

Measurement of frequency

Hertz

307

Measurement of x-ray

eV

308

Which wavelength is longer, x-ray or visible light

Visible light

309

Which wavelength is shorter, infrared or radio (microwave)

Infrared

310

X-rays that originate from the source before they hit the body

Incident beams

311

Photons that disappear, transferring energy to the material

Absorbed

312

Photons that deviate with loss of energy

Scattered

313

Photons that do not interact

Transmitted

314

Composed of atoms

Matter

315

Composed of particles such as protons, neutrons, and electrons

Atoms

316

More dense material results in more

Interactions

317

Increases with density of material

Absorption

318

What can be seen photographically to assess density of various parts of the body

Transmission

319

Reduces quality of an image

Scatter

320

On film, lower absorption equals

Darker film

321

High energy photon is converted into many lower energy photons

Scintillation effect

322

Photon energy is transferred to many lower energy electrons

Photo-electric effect

323

Adding or removing an electron to or from an atom

Ionization effect

324

At rest, atoms of a material are electrically _____________________

Neutral

325

Process by which we measure x-ray quantity and strength

Ionization

326

Effect that is responsible for potential biological damage in x-rays

Ionization

327

Used to measure radiation passing through it

Ionization chamber

328

In an ion chamber, this is proportional to the number of incoming photons

Measurable current

329

Ionization may cause damage to

DNA

330

Damage to DNA may cause

Cancer or death

331

Intensity of beam at given point in space

Roentgen

332

There is a direct relation between R and

mAs

333

Electrical charge produced in a unit mass of air

Roentgen

334

1 RAD equals

1 REM

335

Measurement device to determine x-ray exposure

Film badge

336

Absorbed dose equivalent

REM

337

Quantity of energy absorbed

RAD

338

Used to express dose received by an object

RAD

339

Used to express dose received by a patient or radiation worker

REM

340

Another term for patient dose

Surface dose

341

Gray is an example of this type of unit

System International

342

One Gy is equal to

100 RAD

343

One Sv is equal to

100 REM

344

One Gy is equal to this amount of radiation necessary to deliver an absorbed dose of one gray

115 R

345

A typical chest exam produces

2 mREM

346

A typical skull exam produces

7 mREM

347

A typical abdominal exam produces

100 mREM

348

How much natural radiation does a person receive per year on average

200 mREM

349

A typical CT abdomen exam produces

1000 mREM

350

The most frequent interactions occur within an atom's

Outer shell

351

As an electron returns to its original orbit, it

Releases energy

352

99 percent of released energy is converted to

Heat

353

One x-ray photon is created when and electron

Is deflected by the nucleus of an atom or moves to an inner shell after a hole is created by collision

354

German word for braking

Bremsstralung

355

In characteristic radiation, energy of a photon is equal to

Difference between two orbits

356

This radiation type has a narrow spectrum

Characteristic radiation

357

This radiation has a broad spectrum

General radiation

358

Electrons which are slowed

Brems

359

Peaks of energy specific to target material

Characteristic

360

Typical current passing through filament

3-5 amps

361

Attracted to and accelerated towards target anode

Free electrons

362

Has a characteristic peak of 10 kV

Tungsten

363

Has a characteristic peak of 17kV

Molybdenum

364

Has a characteristic peak of 20 kV

Rhodium

365

As kV increases

Photon energy increases

366

60-120 kV x-rays

High energy

367

20-40 kV x-rays

Low energy

368

As mA increases

Photon production increases

369

mA does not affect

Energy of the beam

370

mA does affect

Intensity of the beam

371

Produces a pale image and lack of detail

Low kV

372

Produces a dark and detailed image

High mA

373

Harmful to the patient

Low energy x-rays

374

Used to filter low energy photons

Aluminum or tunsten

375

Defines the specific peak of x-ray

Anode material

376

Reduces harmful and unusable x-rays

Filter

377

Determines the presence of characteristic radiation and its energy

Anode material

378

Affects amplitude of characteristic radiation

Variation in kV

379

Film container must be

Light-proof

380

This will occur if film and screen are not in contact

Loss of detail

381

Turns x-rays into light

Flourescent screens

382

Main purpose of intensifying screens

Reduce patient dose

383

Emits blue light photons

Calcium tungstate

384

Has in intrinsic efficiency of 20%

Rare earth

385

Has an intrinsic efficiency of 5%

Calcium Tungstate

386

More light can be produced by intensifying screen by

Increasing kV

387

More blue light can be produced on calcium tungstate by

Increasing kV

388

Each strip of a sensitometer increases by a factor of

Two

389

Density of film from 0.25 to 2.5

Useful density

390

A film with a density of 2 allows _____________ times the amount of light through than a film with a density of 3

Ten

391

Should have a density less than 0.25

Base plus fog

392

Fast film may appear

Noisy or grainy

393

Slow film has ___________________ than fast film

Finer detail