What’s NEXT?The FDA Center for Devices andRadiological Health (CDRH) collaborateswith the Conference of Radiation ControlProgram Directors (CRCPD) in a uniquefederal-state partnership to characterize theradiation doses patients receive and to docu-ment the state of the practice of diagnosticradiology. Each year the NationwideEvaluation of X-ray Trends (NEXT) surveyprogram selects a particular radiologicalexamination for study and captures radia-tion exposure data from a nationally repre-sentative sample of U.S. clinical facilities.From1973 to 1983 the NEXT program annuallysurveyed facilities performing twelve commondiagnostic x-ray examinations. Exposuredata was collected using manual techniquesselected for a standard reference patient.With the implementation of automaticexposure controlled (AEC) x-ray equipment,it became necessary to develop a method to

simulate the radiographicattenuation properties of areal patient. These phan-toms, as they are referredto, had to invoke a responseby the AEC system similarto that for a real patient fora wide range of practicalx-ray conditions (beamkilovoltage peak, beamquality), yet also had to be

economical, easily transportable, and mostimportantly produce consistent, clinicallyrepresentative results. The first phantoms tobe developed by CDRH were the adultchest and the adult abdomen-lumbosacralspine phantoms, and the adult chest surveysof 1984 and 1986 provided the testingground for the new phantoms. There are

now seven phantoms inthe NEXT family: AdultPA chest, adultabdomen-lumbosacralspine, adult fluoroscopy,dental, pediatric PA chest,computed tomography(CT), and mammography.The CT head phantomused for NEXT is con-

structed to conform to the CT dosimetryphantom parameters specified in CFR1020.33(b)(6). The phantom used for the NEXTmammography surveys is commerciallyavailable, and is approximately equivalent toa 4.2 cm compressed breast. Currently noNEXT survey of mammography is plannedbecause data on U.S. population dose fromthis x-ray exam is collected from the 10,000annual MQSA inspections using the samemammography phantom. The NEXT adultchest, fluoroscopy, and dental phantoms arealso now commercially available.

The NEXT surveys today capture comprehensivedata on the practice of diagnostic radiologyincluding the evaluation of film processingquality, the integrity of the film processingdarkroom environment, x-ray film imagequality, and information about the facility’sgeneral practice. With digital x-ray imagingtechnology now available, the establishedrelationship between patient exposure andfilm image quality will no longer hold forsuch systems. Theimpact on patientexposure can besignificant becausethere is no film tounder- or over-expose. Will facilitiesusing digital x-ray

systems tend to have lower or higher patientexposure levels compared to facilities usingstandard film systems? NEXT will providethe means of answering this question andmany others that relate to FDA’s mission toprotect the general public from unnecessaryexposure to radiation.

On the Horizon...NEXT is finding its way across the U.S.borders, with a number of internationalorganizations and countries requestingNEXT program information as well asphantoms for use in various projects.Organizations expressing such interestinclude the International Atomic EnergyAgency (IAEA), which is developingrecommendations for the determination ofpatient doses in common x-ray exams, andthe American Association of Physicists inMedicine (AAPM), which is working todevelop reference exposure values forcommon diagnostic exams.

NEXT Adult ChestPhantom

NEXT FluoroscopyPhantom

NEXT Dental Phantom

Image Quality Test Tools

For more information on NEXT contact:

Food and Drug Administration1350 Piccard Drive, HFZ-240

Rockville, MD 20850301-594-3332

CRCPD205 Capital Avenue, Frankfort, KY 40601

502-227-4543 ext. 2231www.CRCPD.org

NationwideEvaluation ofX-rayTrends

NationwideEvaluation ofX-rayTrends

Twenty-fiveYears

of NEXT

Twenty-fiveYears

of NEXT

Adult Chest1984 1986 1994 2001*

Entrance Air Kerma (mGy) 0.14 0.14 0.14 0.13Clinical kVp 104 87 101 109Exposure Time (ms) 22 64 31 29Percent using Grids 71 32 79 93Phantom Film Opitcal Density 1.43 1.42 1.67 1.64

Abdomen andLumbosacral Spine

1987/89 1995 1987/89 1995 Abdomen Abdomen LS Spine LS Spine

Entrance Air Kerma (mGy) 3.2 2.8 3.8 3.2Clinical kVp 76 76 79 78Exposure Time (ms) 198 145 371 247Percent using Grids 95 97 96 96Phantom Film Opitcal Density 1.79 1.74 1.20 1.32

Fluoroscopy1991 1996 1996Cardiac 1996

Upper GI Upper GI Cath Labs C-Arm Units

Entrance Air Kerma (mGy/min)H 43 45 38 22Clinical kVp 102 99 82 78Fluoroscopic Tube Current (mA) 2.1 2.3 5.1 3.0Air Kerma Rate w/Contrast* (mGy/min)H 65 67 71 41Maximum Air Kerma RateH 67 70 74 44

H Determined at 1 cm off the table top and does not include contributions from over-table units.

*Cooper is used to simulate the presence of barium contrast medium.

Film ProcessingProcessing % below Darkroom

Speed N 80** Fog (OD)

84 Chest (Hospitals) 96 408 18.9 N/A85 Mammography 91 139 20.9 N/A86 Chest (Private Practice) 86 99 40.4 N/A87 Abdm/LS Spine (Hospitals) 88 261 37.2 N/A88 Mammography 102 176 10.2 N/A89 Abdm/LS Spine (Private Practice) 89 301 41.9 N/A91 Fluoroscopy 96 349 18.6 N/A92 Mammography 98 238 7.1 0.1293 Dental 83 103 49.5 0.0894 Chest (Hospitals) 115 134 4.5 0.0994 Chest (Private Practice) 107 148 15.5 0.1195 Abdm/LS spine (Hospitals) 98 141 7.2 0.0995 Abdm/LS Spine (Private Practice) 92 178 27 0.1295 Chiropractic Facilities 87 62 37.1 0.0995 Mammography* 98 7100 5.0 0.0496 Fluoroscopy 107 316 10.3 0.0697 Mammography* 107 5737 1.0 0.0398 Pediatric Chest 100 380 5.6 0.1399 Dental 99 122 31.0 0.072000 Mammography* 101 9300 1.6 0.02

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

Pediatric Chest1998

Entrance Air Kerma (mGy) .05Clinical kVp 71Exposure Time (ms) 12Percent Using Grids 9.0Phantom Film Optical Density 1.83Most Popular Patient Restraint Method AdultPercent AP / Percent PA 41/59

Dental Intraoral Exam 1993 1999

Entrance Air Kerma (mGy) 1.9 1.6Clinical kVp 72 71Percent Manual Film Processing 29.0 10.0Phantom Film Optical Density 1.48 1.49Percent using D-speed Film 90 85

Mammography

Computed TomographyHead Exam

1990 2000*

MSAD (mGy) 45.9 50.3mAs 459 355kVp 122 127Effective dose (mSv) - 2

Computed TomographyBody Exams Effective Dose (mSv)*

1990 2000*

Chest - 7Abdomen - 7Pelvis - 6

*Results are preliminary.

February 4, 2003

*Results are preliminary.

Note: 1 mR = 0.00876 mGy