• Decrease font size
  • Return font size to normal
  • Increase font size
U.S. Department of Health and Human Services

Radiation-Emitting Products

  • Print
  • Share
  • E-mail

NEXT Data Summaries

Each year the NEXT survey program selects a particular radiological examination for study and collects radiation exposure data from a nationally representative sample of U.S. clinical facilities. Surveys are repeated periodically to track trends as technology and clinical practices change. Since 1973, NEXT has been conducting surveys on examinations related to the adult chest, abdomen, lumbosacral (LS) spine, upper gastrointestinal fluoroscopy, mammography, computed tomography, dental radiography, and pediatric chest radiography. The following is a breakdown by year of the NEXT surveys that have been performed and the corresponding number of facilities surveyed:

 

Next Surveys Performed

Survey Year

Survey Type

Number of Facilities Surveyed

1984

Adult Chest

429

1985

Mammography

232

1986

Adult Chest (Private Practice)

137

1987

Abdomen and Lumbosacral (LS) Spine (Hospitals)

496

1988

Mammography

231

1989

Abdomen and LS Spine (Private Practice)

374

1990

Computed Tomography

264

1991

Upper GI Fluoroscopy

373

1992

Mammography

356

1993

Dental Radiography

322

1994

Adult Chest

314

1995

Abdomen and LS Spine

240 Abdomen /

          320 LS Spine

1996

Upper GI Fluoroscopy

344

1998

Pediatric Chest

397

1999

Dental Radiography

342

2000

Computed Tomography

265

2001

Adult Chest

220

2002

Abdomen and LS Spine

*200

2003

Upper GI Fluoroscopy

*

*As of 8/03       

The NEXT surveys today capture comprehensive data on radiation exposure and image quality associated with the practice of medical diagnostic radiology. Among the data obtained are the evaluations of film processing quality, the integrity of the film processing darkroom environment, x-ray film-image quality, and information about the facility's general practice.

 The following are data summary tables for the NEXT exams that have been performed:

Adult Chest Exam

 

2001

1994

1986

1984

Number of Facilities

220

314

137

429

Entrance Air Kerma (mGy)

0.13

0.14

0.14

0.14

Clinical kVp

109

101

87

104

Exposure Time (ms)

29

31

64

22

Percent Using Grids

93

79

32

71

Phantom Film Optical Density

1.64

1.67

1.42

1.43

Abdomen Exams

 

2002

1995

1989

1987

Number of Facilities

*200

240

374

496

Entrance Air Kerma (mGy)

2.73

2.82

3.39

3.23

Clinical kVp

75

76

78

75

Exposure Time (ms)

306

145

371

247

Phantom Film OD

1.83

1.74

1.73

1.80

Half-Value Layer (mm Al)

3.1

3.0

3.1

3.2

*Preliminary      

Lumbosacral Spine Exams

 

2002

1995

1989

1987

Number of Facilities

*200

320

374

496

Entrance Air Kerma (mGy)

3.21

3.22

3.85

3.71

Clinical kVp

78

78

80

77

Exposure Time (ms)

351

145

371

247

Phantom Film Optical Density

1.41

1.32

1.26

1.15

Half Value Layer (mm Al)

3.2

3.0

3.1

3.2

*As of 8/03       

Fluoroscopy- Upper GI Exam and Special Topics

 

1996

1996

1996

1991

Number of Facilities

321

25

52

320

Type

Upper GI

Cardiac Catch Labs

Mobile C-Arm Units

Upper GI

Entrance Air Kerma Rate (mGy/min)

45

38

22

43

Clinical kVp

99

82

78

102

Tube Current (mA)

2.3

5.1

3.0

2.1

Air Kerma Rate with  contrast* (mGy/min)

67

71

41

65

Maximum Air Kerma Rate (mGy/min)

70

74

44

67

*Copper is used to simulate the presence of barium contrast

Pediatric Chest Exam

 

1998

Number of Facilities

397

Entrance Air Kerma (mGy)

.051

Clinical kVp

71

Exposure Time (ms)

12

Percent Using Grids

9.0

Phantom Film Optical Density

1.73

Patient Restraint Method

Most Frequent Used

Adult

Percent AP / Percent PA

40/60

Dental (Intraoral) Exam

 

1999

1993

Number of Facilities

342

320

Entrance Air Kerma (mGy)

1.60

1.90

Clinical kVp

71

72

Percent Manual Film Processing

10.0

29.0

Phantom Film Optical Density

1.49

1.48

Percent using D-speed Film

65

90

Computed Tomography

Head Exam (axial scanning)

 

2000

1990

MSAD (mGy)

50.3

45.9

mAs

347

459

kVp

127

122

Effective Dose (mSv)

1.2

--

Body Exams (helical scanning) - Effective Dose (mSv)

 

2000

1990

Chest

9.3

--

Abdomen+Pelvis

13.7

--

Abdomen9.1--
Pelvis

6.2

--

Darkroom Fog and Film Processing

Darkroom fog is a measure of optical density on clinical radiographs that results from ambient light conditions in the darkroom.  Darkroom fog can result from light leaks, improper safelight conditions from the use of inappropriate bulbs or damaged filters, and from inadvertent exposure during film storage or handling.

The quality of film processing is evaluated by a procedure known as the "Sensitometric Technique for the Evaluation of Processing" or STEP. This test utilizes a selected control batch of radiographic film with a pre-determined sensitometric curve when processed according to film manufacturer recommendations. The control film is flashed by a sensitometer and then processed the same way as film is processed normally at the facility. A comparison is made of the optical densities obtained at the facility with what should be obtained were the control film processed as required by the film manufacturer. Any deviation of the control film optical density produced at the facility from what should be obtained were the facility processing according to the "gold standard" determines the extent of under- or over-processing of the film by the facility. The resulting processing speed value is then determined, with a speed range of 80 to 120 considered acceptable for standard cycle processing. Under processing, which corresponds to a processor speed value of below 80, is an inefficiency that maybe inappropriately compensated with increased radiation exposure to patients.

The following is an overall survey comparison of Film Processing and Darkroom Fog:

Year

Survey Type

N

Mean Processing Speed

Percent (%) of Under-processing**

Darkroom Fog (OD)

1984

Chest (Hospitals)

408

96

18.9

N/A

1985

Mammography

139

91

20.9

N/A

1986

Chest (Private Practice)

99

86

40.4

N/A

1987

Abdomen/LS Spine (Hospitals)

261

88

37.2

N/A

1988

Mammography

176

102

10.2

N/A

1989

Abdomen/LS Spine (Private Practice)

301

89

41.9

N/A

1991

Fluoroscopy

349

96

18.6

N/A

1992

Mammography

238

98

7.1

0.12

1993

Dental

103

83

49.5

0.08

1994

Chest (Hospitals)

134

115

4.5

0.09

1994

Chest (Private Practice)

148

107

15.5

0.11

1995

Abdomen/LS spine (Hospitals)

141

98

7.2

0.09

1995

Abdomen/LS Spine (Private Practice)

178

92

27

0.12

1995

Abdomen/LS Spine (Chiropractic)

62

87

37.1

0.09

1995

Mammography*

7100

98

5.0

0.04

1996

Fluoroscopy

316

107

10.3

0.06

1997

Mammography*

5737

107

1.0

0.03

1998

Pediatric Chest

380

100

5.6

0.13

1999

Dental

122

99

31.0

0.07

2000

Mammography*

9300

101

1.6

0.02

2001

Chest

220

101

5.7

0.10

2002

Abdomen/LS Spine (Hospitals)

41

107

4.2

0.09

2002

Abdomen/LS Spine (Private Practice)

90

104

6.7

0.14

2002

Abdomen/LS Spine (Chiropractic)

15

102

5.3

0.07

*Results are from MQSA inspections

**The range of acceptable processing speed is 80 to 120 (standard cycle), and 100-130 (extended cycle)