AAPM REPORT NO. 33

STAFFING LEVELS AND RESPONSIBILITIESOF PHYSICISTS IN DIAGNOSTIC RADIOLOGY

Published for theAmerican Association of Physicists in Medicine

by the American Institute of Physics

AAPM REPORT NO. 33

STAFFING LEVELS AND RESPONSIBILITIESOF PHYSICISTS IN DIAGNOSTlC RADIOLOGY

REPORT OF TASK GROUP 5DIAGNOSTIC X-RAY IMAGING COMMITTEE

Members

Edward L. Nickoloff (Chair)

James V. AthertonPriscilla F. Butler

Robert Y. L. Chu

Lance V. HefnerMitchell G. Randall

Louis K. Wagner

Consultant Reviewers

Stephen Balter

Joseph S. Blinick

G. Donald Frey

Joel E. Gray

Mary E. Moore

Robert G. Waggener

April 1991

Published for theAmerican Association of Physicists in Medicine

by the American Institute of Physics

DISCLAIMER: This publication is based on sources andinformation believed to be reliable, but the AAPM and theeditors disclaim any warranty or liability based on or relat-ing to the contents of this publication.

The AAPM does not endorse any products, manufac-turers, or suppliers. Nothing in this publication should beinterpreted as implying such endorsement.

Further copies of this report ($10 prepaid) may be obtained from:

American Institute of Physicsc/o AIDC

64 Depot RoadColchester, Vermont 05446

(l-800-445-6638)

Library of Congress Catalog Number: 91-71645International Standard Book Number: 0-88318-913-5International Standard Serial Number: 0271-7344

© 1991 by the American Associationof Physicists in Medicine

All rights reserved. No part of this publication may be re-produced, stored in a retrieval system, or transmitted inany form or by any means (electronic, mechanical, photo-copying, recording, or otherwise) without the prior writ-ten permission of the publisher.

Published by the American Institute of Physics, Inc.335 East 45th Street, New York, NY 10017-3483

Printed in the United States of America

TABLE OF CONTENTS

Page

Report Summary 1

Table 1 AAPM Recommendations on Physics Staffing 2

I. Introduction 3

II. The Need for Diagnostic Physicists 5

III. Professional Responsibilities and Services 6

A. Essential Functions 6

1.2.3.4.5.6.

7.8.9.

10.11.12.

Policies and Procedures 6Quality Control Program 6New Equipment Specification and Evaluation 8Acceptance Testing 8Interface with Maintenance Operations 9Implementation of New ClinicalInstumentations or Procedures 9Radiation Safety Operations 10Radiation Dosimetry 10Preparation for JCAHO andRegulatory Inspections 11Teaching 12Administrative Duties 12Continuing Education 12

B. Development of New Diagnostic Techniques

1. Computer Support2. Mathematical Analysis of Data3. Research and Publications4. Consultation Services5. Other Training Programs

IV. Recommendations for Physics Staffing

Table 2 - Example of Physics StaffingDetermination

V. Conclusions

Appendix I References about PhysicsSupport in Diagnostic Radiology

Appendix II Quality Control Test Procedures

References

13

1313131314

15

17

18

19

27

30

REPORT SUMMARY

This report reviews the need for diagnosticradiological physics services in any facility that providesdiagnostic imaging or related diagnostic techniques. Basedon these needs, the American Association of Physicists inMedicine (AAPM) has developed guidelines for the physicsstaff and support personnel required to manage thediagnostic image quality, radiation safety, and associatedpatient care responsibilities of a facility. Such staffinglevels can assure the regulatory and accreditationrequirements are satisfactorily met.

The AAPM recommendations for physics staffing are basedupon the type and amount of equipment in the radiologyfacility. However, the physics services extend far beyondthe support of the listed equipment. The equipment merelyserves as an index value for assessment of the neededphysics staff. The AAPM recommendations are given in Table#1.

1

Table 1

AAPM Physics Staffing Recommendations

Amount of Equipment Staff Recommendations*For Physicists

I. Diagnostic X-ray

For each mobile radiography unitFor each general x-ray roomFor each mobile fluoroscopeFor each R/F roomFor each Special Procedures RoomFor each digital system**For each CT scanner

II. In Nuclear Medicine

For each scintillation cameraFor each image processing computerFor each SPECTFor each PET

0.015 FTE0.015 FTE0.03 FTE0.05 FTE0.08 FTE0.04 FTE0.08 FTE

0.10 FTE0.25 FTE0.25 FTETBD***

III. Ultrasound

For each ultrasound scanner

IV. MRI

0.015 FTE

For each MRI 0.1 - 0.25 FTE

* These FTE numbers given above pertain only to thephysics staff. Additional staff must be provided to supportthe physics operations. The ratio of support staff tophysicists should be about 1.5:1. The support staff shouldconsist of QC technologists, and radiation safety personnel.See text for specific recommendations on support staff.These recommendations do not include needs generated forengineering services, research projects, special teachingneeds for residents and medical students, or needsassociated with PET scanners.

** This refers to digital radiography or to the digitalcomponent of a fluoroscopy system.

*** To be determined in accordance with need.

I. INTRODUCTION

Diagnostic radiology includes x-ray imaging(roentgenography, computed tomography and fluoroscopy),nuclear medicine imaging, some non-imaging studies withradionuclides, and diagnosis by ultrasound and magneticresonance (MR). Traditionally, radiology departmentsprovide both the technological services and equipment forvarious forms of medical imaging and some non-imagingdiagnostic evaluations. These departments typicallyrepresent the largest financial investment in hightechnology equipment in the medical facility and requirehighly educated professionals to provide satisfactorypatient care. The significant investment in and thecomplexity of medical imaging equipment has increased thedemand for skilled diagnostic medical physics support.Individuals who provide such support are referred to asdiagnostic radiological physicists.

Diagnostic radiological physicists provide professionalservices for selecting, evaluating, monitoring andoptimizing imaging devices. They are also directly involvedin patient care, radiation safety, teaching, andadministrative functions. They play an essential role indeveloping policies and procedures for diagnosticradiological departments.

The American Association of Physicists in Medicine (AAPM)recommends that physicists qualified to practice diagnosticradiological physics be certified in diagnostic radiologicalphysics by an appropriate certifying board. At the time ofthis publication the appropriate boards are the AmericanBoard of Radiology and the American Board of MedicalPhysics, and that of the Canadian College of Physicists.Throughout the rest of this document, qualified radiologicalphysicists may be referred to as diagnostic physicists orsimply as physicists.

In this document, the AAPM Task Group on "Physics ManpowerNeeds in Diagnostic Radiology" summarizes the requisitephysics support for diagnostic imaging departments. Staffsize recommendations are based on the equipment inventory ofthe diagnostic imaging department with emphasis placed onthe primary physics needs generated by each piece ofequipment. Among these needs are radiation safety, qualitycontrol, and acceptance testing. Time devoted to theseconcerns can vary considerably depending on the specificneeds and priorities of individual institutions as well ason the regulatory compliance requirements of differentstates in which the institutions reside. The variations inneeds between types of institutions have not been addressedin the staffing recommendations of this report. It isimportant to note that physics staffing must also address

3

the educational services physicists provide to individualswho work with or around the equipment, as well asresponsibilities for administrative and accreditationrequirements associated with the equipment.

These needs ultimately depend on the equipmentinventory of the department. Basing recommendations onequipment inventory provides a firm foundation for whichthere can be no confusion or misinterpretation. However, itis important to note that the number of physicists requiredfor each piece of equipment must reflect not only the needsdirectly associated with that piece of equipment but alsomany other duties and responsibilities which may not bedirectly related the equipment. It also must reflectadministrative, regulatory, and accreditation workassociated with the equipment.

The recommendation in this document in this documentare based upon the effort required to perform the variousduties typically requested of physicists in diagnosticradiology facilities. The information provided in thisreport should be beneficial to administrators, departmentaldirectors, radiologists, physicists, and other health careprofessionals when assessing their diagnostic physicsstaffing needs.

4

II. THE NEED FOR DIAGNOSTIC PHYSICISTS

The increasing sophistication, complexity, high cost, andhigh technology of medical imaging equipment has created anincreasing demand for experts who can ensure that thefinancial investment in these technologies is fully realizedin daily performance. Physicists are experts in thescientific and mathematical principles of imaging as well asin the technology behind the performance evaluation ofmedical imaging and non-imaging diagnostic devices. Theyare trained in the safe uses of all forms of radiationsemployed in a diagnostic department Their goal is to helpestablish a cost-effective and consistent high standard ofdiagnostic image quality, radiation safety, and patientcare. Their scientific expertise spans the spectrum of theimaging technologies from conventional x-ray to ultrasoundand nuclear medicine, from CT and digital angiography tomagnetic resonance (MR). In meeting the above goals aphysicist can help ensure that federal, state and localregulatory requirements for radiation safety are met.Current JCAHO accrediation standards require, in addition toquality image performance and radiation safety, that eachinstitution evaluate radiation exposures to patients (SeeAppendix I, Item 1, Section DR.2.2.10.2). Several documentsthat discuss regulatory and accreditation requirements andother needs addressed by physicists are cited in Appendix I.

5

III. PROFESSIONAL RESPONSIBILITIES AND SERVICES

The professional activities and services provided bydiagnostic physicists can be divided into three categories.These are:A.

1.

2.

3.

B.

Essential functions to:

Meet the clinical demand for excellence in imaging andpatient care while providing a safe radiationenvironment, and

To ensure compliance with various regulatoryrequirements, and

To help promote cost effective operations throughimproved equipment selection, utilization and to ensureconsistency through routine quality controlevaluations.

Optional research and developmental activities forthose facilities involved in the advancement of newtechnologies and procedures.

These responsibilities are discussed below.

A. Essential Functions

1. Policies and Procedures

As defined by the Joint Commission on Accreditation ofHealthcare Organizations (JCAHO), policies and procedures indepartments of diagnostic radiology and nuclear medicine aredesigned to "assure effective management, safety, properperformance of equipment, effective communication andquality control..." Because these departments are heavilyinvested in a variety of radiation producing equipment thatrequires continual monitoring for safety and quality, theradiological physicists play an essential role in developingthe policies and procedures in the respective departments.This essential role is recognized in the JCAHO requirementthat the policies and procedures be reviewed periodically bya medical radiation physicist in order to meet this need.(See Appendix I, Item 1, Section DR.2.1.1.).

2. Quality Control Program

As defined by the American College of Radiology (ACR),Quality Assurance is the overall program required to assureproper medical care is provided to patients. The QualityAssurance program includes the monitoring of medicalrecords, patient handling, medical procedures and safetypractices. Quality Control (Q.C.) is a portion of theoverall Quality Assurance program. Quality Control is a

periodic monitoring of aspects of precision or accuracy asthey relate to the equipment, techniques, or testing ofequipment performance rather than clinical decision-making(ACR Q.A. Guide, 1983). JCAHO and regulatory agenciesrequire that QC programs under the direction of a qualifiedexpert be established at all radiology facilities (SeeAppendix I, Item 1, Sections DR.2.2.7, DR.2.2.10, NM.2.2.8and NM.2.2.14).

Physicists should direct and be responsible for theQuality Control programs. The foremost goal of theseprograms is to obtain and maintain optimal image quality andreliability while minimizing radiation exposure and ensuringcompliance with radiation safety requirements. QC programsinclude diagnostic systems that produce or utilize ionizingradiation and other systems such as MR and ultrasound thatutilize non-ionizing radiations. A cost-effective practiceis to designate a QC technologist to perform some of themeasurements under the supervision of a physicist. QCtechnologists are individuals who are familiar with both theradiology equipment and the test instrumentation. They arespecifically trained to make some of the measurementsrequired to assess imaging equipment performance. QCtechnologists are usually ARRT (American Registry ofRadiological Technologists) certified x-ray or nuclearmedicine technologists who have at least several yearsexperience working with radiology equipment and ionizingradiation.

QC programs include daily, weekly, monthly and semi-annual surveys and spot checks of all imaging equipment andrelevant non-imaging instrumentation. For instance, dailychecks may be performed for film processors; weekly checksmight include certain functional and image qualitymeasurements to detect more gradual changes in imageperformance; and semi-annual evaluations may includecomplete assessments of the image quality, generatorcalibrations and safety checks to assure long-term stabilityof the entire system. This testing is designed to detectproblems before serious malfunctions in the equipment occur.Thus, the tests result in improved equipment "up-time" andperformance. Moreover, patient radiation exposures areoptimal for properly functioning equipment. Such QC testingrequires about 2-4 person-days per year for eachradiographic tube (x-ray tube or image intensifier).

The tests will also result in cost savings. Repeatrates of films are reduced. Studies have shown that QCprograms typically reduce rates from 10-14% to 5-7% whichrepresents a significant saving in film cost, personnel timeand increased patient throughput (see for instance: QualityAssurance Programs for Diagnostic Facilities, HEWPublication (FDA) 80-8110, 1980; and Barnes et al, SPIE Vol.96, 1976, p. 19).

A number of different publications have listed QCprocedures that should be performed on diagnostic radiologyequipment. A brief section with references discussing QCtest procedures is included in the Appendix II of thisreport.

3. New Equipment Specification and Evaluation

Physicists provide recommendations and technicalinformation regarding new equipment selection, layout andinstallation. The physics services for new equipmentinstallations include: gathering information on clinicalrequirements and the products to meet such requirements,information analysis, equipment comparison surveys, sitevisits to inspect installations at other hospitals,preparation of technical bid specifications for theequipment performance and optional accessories, evaluationof the manufacturer's bids, room design in conjunction withthe physicians, administrators, architects, and others; andradiation shielding specifications.

For installations of complex and expensive radiologyequipment, these services can result in a considerable costsavings. The amount of time spent performing such servicesdepends on the sophistication of the equipment and thestatus of the room in which it will reside. For example,the effort for a simple conventional x-ray room may requireone week's work but for an angiographic suite, up to sixweeks may be required to complete all the above mentionedservices. Since the average life of x-ray equipment istypically 7-10 years (AHA, Estimated Useful Lives ofDepreciable Hospital Assets, 1983), a replacement schedulecan involve 10-15% of the existing equipment each year.

4. Acceptance Testing

After new rooms are installed, physicists test theperformance of the equipment to ensure that the quality ofperformance is commensurate with the investment, and thatperformance complies with the technical specificationsitemized in the purchase contract. This testing should bethe most thorough evaluation that the equipment willundergo. It involves mechanical checks, electronicevaluation of generator calibrations, radiation safetyevaluations, image quality assessments and overall systemperformance measurements. These tests provide the baselinedata for future quality control checks. The time allottedto complete these tests inevitably depends on the complexityof the equipment and the degree to which performancespecifications are met following installation by themanufacturer.

The time necessary for acceptance testing can range from oneday up to perhaps four to six weeks. Because of thevariability in systems, it is impossible to give a firm costfigure for the services discussed under sections 3 and 4. Ageneral figure of one percent of the capital equipment costsprovides a guideline value. This is returned on improvedequipment performance.

5. Interface with Maintenance Operations

Effective maintenance is a necessary part of a QCprogram. Physicists cooperate with maintenance and in somecases direct maintenance personnel to ensure appropriaterepair, calibration and preventative maintenance ofradiology equipment. Following major repairs, replacementor preventative maintenance of radiology equipment, thephysicist checks the equipment for function, image quality,and safety. The physics services also include theevaluation of new x-ray tubes for specified focal spotsizes, filtration, output, leakage radiation, andcalibration. Replacement image intensifiers are checked forconversion efficiency, spatial resolution, contrast ratio,uniformity, linearity, and input dose rates. Similarmeasurements are performed following major repairs or partsreplacements.

Physicists help "trouble shoot" equipment problems andare frequently mediators who resolve whether malfunctionsare due to operator error, ancillary equipment malfunction(film or processor problems) or electronic problems. Withgood maintenance records, the physicist's input can be usedto effectively budget for equipment replacement needs aswell as reduce cost by eliminating unnecessary orinappropriate purchases of x-ray tubes, image intensifiersand other equipment. In addition, safety problems may beuncovered and corrected under the physicist's directionsbefore serious hazards occur.

6. Implementation of New Clinical Instrumentation orProcedures

Physicists often assist in the initial implementationof new high technology equipment or new clinical proceduresnot previously provided at an institution. Examples of hightechnology equipment with which physicists provideassistance include: Picture Archiving and CommunicationsSystems (PACS), teleradiology, digital radiology systems,new CT scanner procedures, MR units, computer software,computer reporting systems, personal computers and similaritems.

9

7. Radiation Safety Operations

A separate radiation safety office may or may not existin a given hospital. Even when a separate radiation safetyoffice does exist, many primary radiation safety duties arestill the responsibility of a diagnostic radiologicalphysicist. A diagnostic physicist has special training inradiological safety which prepares him for these functions.The safe use of ionizing radiation is of concern to not onlythe personnel working at the hospital but also to thepatients and general public. Personnel dosimeters must beissued to radiation workers. The physicists must makecertain that the dosimeters are worn and the reports arereviewed. Safe use of equipment and sources producingionizing radiation must be established and instituted.Records and inventories of radioactive sources must bemeticulously maintained. Procedures manuals must bedeveloped. Wipe tests for radioactive contamination must betaken at regular intervals. Leaded aprons must be inspectedat least annually. Radiation room shielding design must beperformed for new installations to determine adequateshielding thickness. Radiation surveys of the shieldedrooms such as fluoroscopic areas and isotope areas must beperformed regularly. Training sessions are used to instructradiology personnel about the proper use of radiationproducing equipment and shielding devices. All of the aboveshould be written in as part of -the departmental policy andprocedures.

As the size of a facility increases, radiation safetyneeds inevitably become more complex because of increasedtraffic in and out of radiation producing areas and becauseof increased mobility of radiation sources used throughoutthe facility for patient care. In order to assure adequateprotection to the public and personnel, the number ofradiation safety personnel required to support largerfacilities may be greater in proportion to their size thanthe number required to support small facilities. Largerfacilities should carefully assess any extra radiationsafety personnel, beyond those recommended in this report,who may be required to provide adequate control ofradiation. At a minimum, a 400 bed hospital requires 0.4FTE physicist to handle radiation safety.

8. Radiation Dosimetry

Physicists are frequently requested to provideinformation on radiation dose or exposure to patients orstaff. Measurement of radiation dose is referred to asdosimetry. Patient dosimetry is also performed to ensurethe safety of patients, to comply with JCAHO requirements,and to compare doses and exposures with regulatoryguidelines or national averages. Dosimetry may be performed

10

to determine why a high radiation badge reading occurred, toestimate fetal dose for patients or staff, or to evaluateexisting shielding devices. The estimates may involvemeasurement with phantoms or direct measurements.Physicists also handle inquires from patients and thegeneral public about radiation levels and effects.

9. Preparation for JCAHO and Regulatory Inspections

JCAHO inspections are frequently limited to audits ofthe records to ensure appropriate physics services areprovided. Nevertheless, JCAHO requires that an ongoingQuality Control (QC) program to "maximize the quality ofdiagnostic information for diagnostic radiology." Allradiation producing equipment must be checked by thephysicist at least once per year. Moreover, patientradiation exposure calculations for typical proceduresperformed in each room must be determined from measurementsmade on each x-ray tube. The physicist should audit theexposures to ensure the requirements for JCAHO have beenadequately addressed.

State or local regulatory agencies usually conductinspections that involve testing of the equipment andradiation surveys of the facilities. Deficiencies uncoveredduring inspections by State or local regulatory agencies canresult in significant fines or restrictions placed upon theradiological facility. Regulatory requirements of variousradiation control agencies typically include annualcalibration reports on each piece of x-ray and nuclearmedicine equipment that produces or measures ionizingradiation. Complete records must be kept on all radioactivesources. Area surveys of radiation levels around theseradiation producing devices must be obtained and documented.

To meet these requirements, physicists must makenumerous measurements and maintain detailed and completerecords. Prior to an inspection, equipment is usuallyrechecked and repaired. The physicists frequently meet withthe inspectors, schedule the inspection of the equipment,review the inspection procedures, review the findings andarrange for corrective actions as required.

Between 0.2 to 1.0 days may be required per room toadequately prepare for the above inspections. The actualtime depends on the equipment and the size of the facility.In some states, regulations are stricter than in otherstates and this adds to the effort.

11

10. Teaching

Physicists are responsible for teaching health andimaging aspects of radiological physics to radiologyresidents. Additionally, the physicist frequently teachesradiation safety and radiation effects to medical students,technologists, residents, radiology staff, nurses, securitypersonnel and housekeeping staff. Diagnostic radiologyresidents must be prepared to pass written boardexaminations containing a significant number of physicsquestions. Considering the large number of topics whichmust be taught, the resident courses should have asignificant number of in-class hours and laboratorysessions. The Nuclear Regulatory Commission (NRC) requiresthe nuclear medicine residents to have a minimum of 200classroom hours in order to become licensed (See Appendix I,Item 13). Residents should have a minimum of 50 classroomhours of instruction per year.

For institutions with residency programs and/or studenttechnology programs in radiology, lectures are intended toprovide fundamental knowledge about scientific principles,an understanding about imaging equipment, to enhance theirability to properly utilize clinical devices, and to providean understanding about the hazards and safe usage ofionizing radiation. The usual criteria for estimatingteaching loads is one to three hours of preparation forevery hour in the classroom.

11. Administrative Duties

A certain percentage of every diagnostic radiologicalphysicist's time is devoted to administrative duties. Theseitems include writing reports, preparing operating budgets,maintaining equipment files, attending committee meetings,communicating with administrators, requesting the purchase,repair and calibration of physics equipment and othersimilar functions. In large institutions, the chiefphysicist inevitably incurs increased administrative dutiesabove those of the average physicist.

12. Continuing Education

It is essential that the need for continuing educationof medical physicists be recognized and that appropriatetime be allotted. Physicists should attend professionalmeetings, refresher courses, scientific sessions andtechnical exhibits to remain abreast of innovativedevelopments in new equipment, techniques, and other medicalimaging issues. Physicists should also keep abreast ofinformation in technical and clinical publications. About5%-10% of a physicist's time should be dedicated tocontinuing education.

12

B. DEVELOPMENT OF NEW DIAGNOSTIC TECHNIQUES

1. Computer Support

Physicists' knowledge of computer systems enables themto assist the physician to develop or modify clinicalstudies which utilize this equipment. Examples of theseservices include but are not limited to: Quantitativeanalysis of nuclear medicine images; display, reformattingand analysis of CT images; processing of digital radiologydata; and analysis of cardiac images for ventricularperformance indices.

2. Mathematical Analysis of Data

Many clinical studies require someone to analyze theclinical data in some mathematical fashion. These types ofanalyses may include: statistical analyses such as linearregression and correlation studies, mean and standarddeviation, T-tests, sensitivity-specificity studies,receiver operating characteristic (ROC) curves, and manyother types of calculations. Clinical examples includeestablishing the evaluation of ventilation-perfusion andrenal flow studies in nuclear medicine as well as cardiacfunction and bone mineral determinations in diagnosticradiology. A physicist's strong training in mathematicsenables him to provide technical advice and assistance inthe appropriate analysis of clinical data. Once theanalyses are established, a trained technologist performsthese functions, but a physicist should periodically monitorthe adequacy of these evaluations.

3. Research and Publications

At most large medical facilities, physicists areexpected to assist the radiologists with both basic andclinical research. A diagnostic physicist's training inmechanics, electronics, mathematics, chemistry, physiologyand clinical exposure permits him to bring a strongscientific background to many research projects. If thisfunction is appropriate for the institutional position, thenextra time should be allocated for physicists to perform thelibrary research and to do pilot studies necessary todevelop research proposals that are submitted for fundingconsideration. Efforts to write articles intended forpublication in journals and for presentation at professionalmeetings must also be considered.

4. Consultation Services

Physicists are often requested to provide advice andtechnical assistance to other departments in the medicalinstitutions; these include dentistry, cardiology, urology,

13

surgery and orthopedics. The physicist's broad area ofexpertise for medical imaging can be applied acrossdepartmental lines in medical institutions.

5. Other Training Programs

Physicists are involved in training programs fortechnologists, other radiological physicists, andphysicians. Often facilities have special short courses toprovide training for physicians and technologists so thatthey understand radiation safety principles in theutilization of high technology equipment. This training maybe on an individual basis or at local and national meetings.

14

IV. Recommendations for Physics Staffing

The recommendations in this document for physicsstaffing utilize an itemizations of equipment within thefacility. These recommendations are summarized in Table 1.The recommendations address the primary needs generated byeach piece of equipment at the institution as well as otherindirectly related requirements for radiological physicsservices. These needs include quality control, radiationsafety, replacement of aging equipment, regulatoryrequirements, educational activities for the staff,clinically related needs and administrative functions.

These recommendations do not include needs generatedfor research projects, special teaching needs for residentsand medical students, or needs associated with PET scanners.The needs required by each institution to fulfill thesespecialized function vary greatly. Therefore, eachinstitution should allocate positions for physicists on thebasis of their teaching demands, services provided at thePET facilities, and the emphasis they place upon research.

In addition to the required physics staff, there mustbe some provision to provide support personnel to assist thephysicists. Physicists are often assisted in theperformance of their various services in a diagnosticfacility by QC technologists, processor monitoringRadiation Safety technicians and other supportstaff. QC technologists are utilized to assist thephysicists with various routine QC measurements in order tomake a more effective use of the physicist's time. The QCtechnologists may directly perform the more routinemeasurements on the less sophisticated radiology equipmentwhich they review with the physicists.

For example, the monitoring of automated filmprocessors is an essential function that must be performedon a daily basis. Some regulatory codes mandate the dailymonitoring of film processors with sensitometry films. Thesensitometry films are usually exposed, processed in eachfilm processor, measured and plotted by a designatedprocessor QC technician. For a facility with many filmprocessors, the monitoring operations can require asignificant expenditure of effort. Similarly, the RadiationSafety technicians may be involved with many assortedservices from the distribution of radiation badge monitorsto the disposal of radioactive waste from nuclear medicineand research laboratories. Other Radiation Safetyoperations involve monitoring of the proper use ofradioactive materials and radiation producing facilities,licensure and various recordkeeping functions.

15

The number of physics support staff can be directlyrelated to the number of FTE physicists. In this document,the recommendations for physics support staff are 1.5 FTEsupport staff per physicist. The physics support staffwould be comprised of QC technologists, processor monitoringpersonnel, Radiation Safety technicians and other associatedpersonnel.

In order to illustrate the application of the staffingrecommendations given in Table 1 of this report, an exampleof a medium size diagnostic radiology facility is used. Theequipment in this facility may be similar to that found in a400-600 bed hospital. The facility in this example has 22x-ray rooms, 1 CT scanner, 7 mobile x-ray units, 2 nuclearmedicine imagers, 1 SPECT device and 4 ultrasound units.The equipment is categorized according to type in Table #2.

The recommended physics support for this facility iscalculated based upon the number and type of radiologyequipment contained in the facility. Based upon therecommendations, in this report, the facility* should employ1.72 FTE physicists and 2.58 FTE support staff. The x-rayoperations would require a full-time-physicist; and thenuclear medicine, ultrasound and radiation safety operationswould require the services of a part-time physicistexpending approximately 50%-70% effort.

In order to perform the various physics service for thefacility in the example, the recommended staffing seems tobe reasonable. The number is also consistent with a 1973USHEW (FDA) recommendation that each hospital with more than300 beds have a least one full-time professional medicalphysicist. (Appendix I, reference 11) The USHEW (FDA)recommendations were written before the implementation ofconsiderable high technology equipment in diagnosticradiology facilities; and therefore, it represents a lowerlimit to estimating necessary physics support.

16

Table 2. The equipment of a facility and FTE physicists andsupport staff are summarized as follows:

Equipment

15 general x-rayrooms

4 RF rooms

3 special proceduresrooms

2 digital systems

1 CT scanner

5 radiographicportable units

2 portable fluoro-scopic units

2 nuclear medicineimagers

1 image processingcomputer

1 SPECT unit

4 ultrasound units

FTE's perEquipment

0.015/room

0.05/room

0.08/room

0.04/system

0.08/room

0.0l5/unit

0.03/unit 0.06

0.10/unit

0.25/unit

0.25/unit

0.015/unit

RecommendedFTE Physicists

0.225

0.20

0.24

0.08

0.08

0.075

0.20

0.25

0.25

0.06

Total........................................l.72

Practical Staffing: 2.0 FTE Physicists and 2.6 (1.5 x 1.75)FTE Support Staff

The facility could hire 1 full-time physicist in x-ray withan additional 72% part-time physicist in Nuclear Medicine,Ultrasound and Radiation Safety operations. In practicalterms, 2 physicists are appropriate. The appropriatephysics support staff is 2.6 FTE's.

17

V. Conclusions

Guidelines have been set for estimating the number ofappropriate physics staff and their support personnel for agiven facility. These recommendations use the type andamount of radiology equipment as an index to estimate theamount of physics support required. Even though somephysics services are not directly related to the equipment,this method serves as a mechanism that can be unambiguouslyutilized to obtain a value for the amount of physics staffthat should be provided in a given radiology facility.

This document recommends that the total number of fulltime equivalent physicists be determined separately from thesupport staff. In this way, both the values for thephysicists and the support personnel can be appropriatelydetermined.

In many instances, the numbers for staff size generatedby use of Table 1 will contain fraction of personnel. Theneeds of the department can be fulfilled by hiring part-timeequivalent individuals or consultant physics services toprovide the necessary physics support. However, allradiologic facilities should have some support from adiagnostic radiological physicist to handle their diagnosticradiological physics needs. For small diagnostic radiologyfacilities in which less than one physicist is required, aphysicist should be employed as a consultant or on a part-time basis in order to supervise the physics operations.

The data given in this report should enableadministrators, departmental directors, radiologists,physicists. and other health care professionals to assessproperly the diagnostic physics staffing requirements fortheir particular medical facility. The information shouldaid in-the evaluation of the need for increased staffmembers required as new equipment is purchased or as thedepartment expands. Following these guidelines will providean institution with a competitively consistent high standardof diagnostic image quality, radiation safety and patientcare necessary to meet the requirements of today'sincreasingly technologically complex radiology facilities.

Acknowledgements

Consultant reviewers to the committee in preparation ofthis document include Stephen Balter, Ph.D.; Joseph S.Blinick, Ph.D.; G. Donald Frey, Ph.D.; Joel E. Gray, Ph.D.;Mary Moore, M.S.; and Robert G. Waggener, Ph.D.

18

Appendix I

References on Physics Support in Diagnostic Radiology

1. Joint Commission on Accreditation of HealthcareOrganizations"Standard"

DR.2 There are policies and procedures to assureeffective management, safety, properperformance of equipment, effectivecommunications, and quality control in thediagnostic radiology department/service.*

Required Characteristics

DR.2.1 Policies and procedures are developed incooperation with the medical staff,administration, nursing services, and, asnecessary, other clinical departments/services, and are implemented.*

DR.2.1.1 The policies and procedures arereviewed periodically by a medical radiationphysicist.

DR.2.1.2 The policies and procedures arerevised when necessary.

DR.2.1.2.1 Each revision is documented.

DR.2.2. The written policies and procedures include,but need not be limited to, the following:*

DR.2.2.7 A quality control program designedto minimize patient, personnel, and publicrisks and maximize the quality of diagnosticinformation;*

DR.2.2.9 Compliance with applicable law andregulation

DR.2.2.10 Provisions that a qualifiedphysician, qualified medical radiationphysicist, or other qualified individual*

DR.2.2.10.1 Monitors performance evaluationsof diagnostic and treatment equipment atleast annually;* and

DR.2.2.10.2 Monitors doses from diagnosticradiology procedures.*

19

* Indicates

DR.2.2.11 With respect to radiation hazardsfrom equipment, adherence to therecommendations of any currently recognizedand reliable authority on radiation hazards,such as the National Council on RadiationProtection and Measurements, and anyrequirements of appropriate licensingagencies or other government bodies:

DR.2.2.12 Guidelines for protecting personneland patients from radiation.

DR.2.2.13 The monitoring of staff andpersonnel for exposure to radiation.

DR.2.2.14 Guidelines developed inconsultation with infection control committeefor the protection of staff, patients, andequipment;

DR.2.2.15 Orientation and a safety educationprogram for all personnel.

key factors in the accreditation decisionprocess. From: Accreditation Manual for Hospital, JointCommission on Accreditation of Healthcare Organizations,1988.

2. Joint Commission on Accreditation of HealthcareOrganizations"Standard"

NM.2 There are policies and procedures to assureeffective management, safety, properperformance of equipment, effectivecommunication, and quality control in thenuclear medicine department/service.*

Required Characteristics

NM.2.1 Policies and procedures are developed incooperation with the medical staff,administration, nursing services, and, asnecessary, other clinical departments/services, and are implemented.*

NM.2.1.1. The policies and procedures arereviewed periodically by a medical radiationphysicist

NM.2.1.2 The policies and procedures arerevised when necessary.

20

NM.2.1.2.1 Each revision is documented.

NM.2.2 The written policies and procedures include,but need not be limited to, the following:*

NM.2.2.8 A quality control program designedto minimize patient, personnel, and publicrisk and maximize the quality of diagnosticinformation.*

NM.2.2.10 The maintenance of records onradionuclides and radiopharmaceuticals fromthe point of administration and finaldisposal;

NM.2.2.10.1 Information in the recordsincludes, at least,

NM.2.2.10.1.1 The date, method of receipt,identity of radionuclide, activity, anddisposal;

NN.2.2.10.1.2 Supplier and lot number

NM.2.2.10.1.3 Identity of recipient,identity of radionuclide, activity ofradionuclide administered, and date

NM.2.2.11 Safety policies, including

NM.2.2.11.1 The receipt, storage, transport,preparation, handling, use, and disposal ofradionuclides;* and

NM.2.2.11.2 Implementation of standard PL.6through required characteristic PL.6.10 inthe "Plant, Technology, and SafetyManagement" chapter of this Manual (for themanagement of hazardous materials).*

NM.2.2.12 Compliance with applicable law andregulation.

NM.2.2.13 For purposes of standardizingequipment performance, radiation standardshaving energies equivalent to thoseradionuclides used in patient studies.

NM.2.2.14 Provisions that a qualifiedphysician, qualified medical radiationphysicist, or other qualified individual*

21

NM.2.2.14.1 Monitors performance evaluationsof diagnostic equipment on a quarterlybasis;*

NM.2.2.14.2 Monitors doses administered topatients for acceptable agreement withprescribed doses;*

NM.2.2.14.3 Monitors, for validity,quantitative results obtained fromprocedures; and*

NM.2.2.14.4 Monitors absorbed doses ofradiation in individual patients as requestedby the director.*

NM.2.2.15 Guidelines for protecting personneland patients from radiation.*

NM.2.2.16 The monitoring of staff andpersonnel for exposure to radiation.*

NM.2.2.17 The monitoring of receipt, storage,preparation, and use areas for radionuclidecontamination.*

NM.2.2.18 Guidelines to be followed in theevent of radionuclide contamination of theenvironment, patients, personnel, orequipment.

NM.2.2.19 Guidelines developed inconsultation with the infection controlcommittee for the protection of staff,patients, and equipment.

NM.2.2.20 Orientation and a safety educationprogram for all personnel.*

* Indicates key factors in the accreditation decisionprocess. From: Accreditation Manual for Hospitals, JointCommission on Accreditation of Healthcare Organizations,1988.

3. "Medical physicists should be responsible for thepractical aspects of diagnostic radiology, includingquality control. The medical physicist's teachingobligations should reflect this practical involvement.From Quality Assurance for Diagnostic ImagingEquipment, NCRP Report No. 99, 1988.

4. "Before x-ray equipment is put into regular use,complete radiation safety surveys shall be carried

22

out." From Radiation Protection for Medical and AlliedHealth Personnel, NCRP Report No. 48, 1976.

5. "All new installations and existing installations notpreviously surveyed shall have a Radiation ProtectionSurvey performed by or under the direction of aqualified expert. From Structural Shielding Design andEvaluation for Medical Use of X-rays and Gamma Rays ofEnergies Up to 10 meV, NCRP Report No. 49, 1976.

6. "In larger radiation utilization programs, a qualifiedindividual should be designated as the Radiation SafetyOfficer. ... Specialized education in health physics atthe undergraduate or college level, combined withpractical experience, is preferable." From OperationalRadiation Safety Program, NCRP Report No. 59, 1978.

7. "An adequate diagnostic quality assurance (QA) programinvolves periodic checks of components in a diagnosticx-ray imaging system. The optimum QA program for anyindividual facility will depend on a number of factorswhich include, but may not necessarily be limited to,items such as the type of procedures performed, type ofequipment utilized and patient workload. The programshould be developed under the guidance and supervisionof a medical physicist qualified in this area ofexpertise by education, training and experience."from Basic Quality Control in Diagnostic Radiology,American Association of Physicists in Medicine (AAPM)Report No. 4, 1978.

8. "Who needs a Radiological Physicist? Every facilitywith any of the following: x-ray generating equipment,nuclear medicine imaging equipment, ultrasound or MRIequipment, radioisotope laboratory, research utilizingradioactive materials, radiation therapy equipment,plans to acquire any of the above mentioned equipment,and/or education programs for radiology residents,medical students or radiological technologists."from The Radiological Physicist, American College ofRadiology (ACR), 1985.

9. "... in the radiological field (diagnostic imaging,radiation oncology, nuclear medicine and radiationprotection) there is an obvious need for a clinicalmedical physics service... Again, it is the positionof the AAPM that it is high unlikely that optimalimaging (and therefore the best available medical care)can be provided by those imaging departments that donot provide for and use medical imaging services."from The Roles, Responsibilities and Status of theClinical Medical Physicist, American Association ofPhysicists in Medicine (AAPM), 1985.

23

10. QA programs are recommended for all diagnosticradiology facilities and physicists (where available)should play a major role."from Burkhart RL, Quality Assurance Programs forDiagnostic Radiology Facilities, HEW Publications (FDA)80-8110, February 1980.

11. "Periodic measurements using appropriate, calibratedinstruments should be conducted to determine facilities(radiation) exposure levels for the "standardpatients."from Evaluation of Radiation Exposure from DiagnosticRadiology Examination - General Recommendations, USHHSPublications (FDA) 85-8246, August 1985.

12. "Recommendation: At least one full-time professionalmedical physicist is needed in each medical institutionwith more than 300 hospital beds."from Status and Future Manpower Needs of Physicists inMedicine in the United States, USHEW Publication (FDA)74-8014, November 1973.

13. "Sixty hours of documented instruction in Magneticresonance imaging physics, intrumentation and clinicalapparatus are recommended."from MRI Guidelines, ACR Bulletin, Vol. 41, No. 10,October 1985.

14. "Suggested minimal acceptable training of DiagnosticRadiology Physicians with special competence in NuclearMedicine:

a. Radiation Physics and Instrumentation------l00 hours

b. Radiation Protection ---------------------- 30 hours

c. Mathematics pertaining to the use and ----- 20 hoursmeasurement of radioactivity

d. Radiation Biology ------------------------- 20 hours

e. Radiopharmaceutical Chemistry ------------- 30 hours

TOTAL 200 hours

24

For Diagnostic Radiology:

a. Radiation Physics and Instrumentation------l10 hours

b. Radiation Protection ---------------------- 40 hours

c. Mathematics pertaining to the use and ---- 25 hoursmeasurement of radioactivity

d. Radiation Biology _________________________ 25 hours

from Federal Register, Vol. 47, No. 232, December 2, 1982.(With a 3:l ratio of preparation time to classroom hours,the 200 hours of training would amount to 0.40 FTEphysicist.)

15. "Each facility shall establish a committee ofindividuals to be responsible for Radiation Safety andQuality Assurance for those departments within thefacility which utilize x-rays for diagnostic purposes.... the committee should be composed of a minimum ofone Radiologist, the Chief Technologist, the QCtechnologist(s) and a Diagnostic Radiological Physicistand a member of the in-house x-ray service." Thedocument then details the QC testing which is deemednecessary.from Guide for Radiation Safety/Quality AssurancePrograms, New York State Department of Health, Bureauof Environmental Radiation Protection, April 1985.

16 "A large facility (with 15 to 20 rooms) should have afull-time QC technologist and two or more full-timeservice engineers. A facility of this size should havea physicist working at least half-time and available atthe facility 20 hours per week on a fixed schedule. Inaddition, the physicist should be available forconsultation by telephone at all times.from Gray JE, Winkler NT, Stears J and Frank ED:Quality Control in Diagnostic Imaging, AspenPublishers, Inc., Rockville, MD, 1983.

17. "The physicist, who is a member of the team responsiblefor choosing new equipment, provides advice on theperformance characteristics of imaging systems andcomments on the suitability of the equipment forproposed usage. ... Performance assessment deals withthe relationship between dose and image quality for anyparticular imaging system and clinical application.... Regular monitoring of equipment, including retake

25

and reject analysis, is necessary to ensure effectiveoperation and image quality."from The Role of the Medical Physicist in theScientific and Technical Support of Diagnostic X-rayServices, Hospital Physicists' Association, London1985.

18. "... The physicist should be responsible for evaluatingperformance characteristics of new diagnosticequipment... Physics instruction of diagnosticresidents should be given by a physicist..."from Nice CM and Bushon SC, The Diagnostic RadiologicPhysicist, Radiology 109:225-226, October 1973.

19. "It is the position of the College that ABR Certifiedradiological physicists (or equivalent) be required (toprovide Quality Control services to the hospitalradiology departments) and that State safetyinspections are conducted to indentify equipmentdeficiencies rather than to assist in improving healthcare quality."from ACR Physics Report, American College of RadiologyAugust 1, 1983.

20. "The new (JCAHO 1987) standards enhance the role ofradiological physicists. The policies and proceduresof the three radiology services must be reviewedperiodically by a medical radiation physicist. Thestandards will also require periodic monitoring ofperformance evaluations of radiologic equipment. Thiswill be done on an annual, quarterly and monthly basis,respectively for diagnostic, nuclear medicine andradiation oncology services: The monitoring will behandled by a qualified physician, medical radiationphysicist or other qualified individual."from ACR Bulletin, American College of Radiology, May1986.

26

Appendix II

Quality Control Test Procedures

In this appendix, the Task Group lists a number ofQuality Control tests which should be routinely conducted inDiagnostic Imaging Departments. The manner in which the QCtests are performed are not described since severalpublications (l-7) are devoted to this topic. Furthermore,a more comprehensive QC program may include a number ofadditional procedures which provide a more detailedassessment of the equipment. The QC procedures enumeratedbelow are the basic tests that are essential to ensureproper and consistent operation of the diagnostic imagingequipment. Associated with QC tests is the necessity todocument results so that trends may be traced andperformance more closely evaluated. Since the many testsare very specific to certain types of equipment such asultrasound units or MR scanners, the items discussed arelimited to the certain x-ray equipment. The test proceduresand an estimation of the frequency for the testing aregiven. Testing frequencies, however, are heavily dependentupon the type of equipment and its clinical usage; certaincritical units may require checks on a monthly or quarterlybasis. The goal of this section is to provide the reader ofthis document with an understanding of the extensive natureof typical QC programs which are normally performed underthe supervision of a diagnostic radiological physicist.

A.

1.

B.

1.

Film Processor Monitoring

Essential test - Processor speed, contrast, base plusfog and developer temperature should be monitored on adaily basis for each processor. These tests could beconducted by a designated quality control technologist.In addition, artifacts on clinical films should beroutinely noted and diagnosed by individualtechnologists or the technologist assigned to qualitycontrol films as they emerge from the processor.

Darkroom Fog

Essential tests - each darkroom should be checked for(sources of unsafe light) at least annually or anytimedarkroom fog is suspected. This test could beconducted by a quality control technologist (orpossibly a darkroom technologist).

27

C.

1.

D.

1.

2.

E.

1.

2.

F.

1.

G.

1.

H.

1.

Screen-Film Contact

Essential tests - new cassettes and/or screens shouldbe checked for screen-film contact prior to acceptance.Cassettes already in use should be checked on an annualbasis or whenever damaged screens or cassettes aresuspected.

X-Ray Tube Checks

Essential tests - half-value layer and consistencychecks should be conducted annually or after a new x-ray tube is installed. Focal spots should be measuredperiodically. In addition, the half-value layer shouldbe checked after any service that requires that thecollimator be removed from the x-ray tube.

Additional tests - checks of the x-ray tube protectivecircuitry should be thoroughly checked prior toacceptance of a new room and subsequently on an annualbasis.

Collimator Checks

Essential tests - x-ray field/light field congruence,collimator accuracy, Bucky tray alignment and automaticcollimator field size should be checked every 6 months,after collimator light changes and after any servicethat requires that the collimator be removed by the x-ray tube.

Additional tests - Bucky grid motions and alignmenttests should be conducted on an annual basis.

Radiographic Generator Checks

Essential tests - exposure reproducibility, mAlinearity, timer reproducibility and accuracy and kVpreproducibility and accuracy should be checked every 6months or following any service to the x-ray generator.

Automatic Exposure Control (AEC) Checks

Essential tests - reproducibility, backup time, minimumexposure time, thickness compensation and kVpcompensation should be evaluated following changes inintensifying screens and every 6 months.

Fluoroscopic Checks

Essential tests - fluoroscopic image size and beamlimitation should be checked every 3 months. Maximumtabletop exposure rates (or maximum entrance exposure

28

2.

I.

1.

2.

J.

1.

K.

1.

2.

rates for above table tubes) should be checked every 6months. At the same time, "standard" entrance exposurerates should be checked using an appropriate phantom.High and low contrast resolution checks of the TVmonitor, screen-film spots, photospots and cine shouldbe conducted every 6 months. Other checks such as HVL,focal spot and AEC performance should be checked asoutlined above.

Additional tests - grid alignment checks andqualitative tests of the automatic brightness controlcan be checked on an annual basis

Tomographic Checks

Essential tests - tomographic cut level, cut thickness,motion completeness and resolution, should be checkedevery 6 months. Other tests for radiographicgenerator, tubes and collimators should be conducted asspecified above.

Additional tests - exposure angle accuracy andtomographic plane flatness can also be checked every 6months.

Patient Entrance Skin Exposure

Essential tests - entrance skin exposures for severalrepresentative projections of a standard patient shouldbe measured on each radiographic (and tomographicsystem) on an annual basis.

Computed Tomography

Essential test - CT number, noise and field uniformityshould be checked via a water phantom daily. Patientdose levels should be measured annually.

Additional tests - contrast scale, high and lowcontrast resolutions and slice thickness accuracy andalignment should be checked on a weekly basis.

Many of the aforementioned tests should be conducted by QCtechnologists under the direction of a diagnosticradiological physicist. However, a diagnostic physicistshould more actively participate in those tests whichinvolve patient dosimetry, image quality evaluations,complex measurements and radiation safety issues.

29

References

1.

2.

3.

4.

5.

6.

7.

8.

9.

10.

Basic Quality Control in Diagnostic Radiology. AAPMReport, No. 4, New York, NY, November, 1977.

Burkhart, RL: Quality Assurance Programs forDiagnostic Radiology Facilities. HEW Publication (FDA)80-8110, February, 1980.

Gray, JE, Winkler, NT, Stears, J and Frank, ED:Quality Control in Diagnostic Imaging. University ParkPress, Baltimore, MD, 1983.

Gray, JE: Photographic Quality Assurance in DiagnosticRadiology, Nuclear Medicine and Radiation Therapy, Vol,I and II. HEW Publications (FDA) 76-8043, June, 1976and 77-8028, July, 1977.

Hendee, WR, and Rossi, RP: Quality Assurance forRadiographic X-ray Units and Associated Equipment. HEWPublications (FDA) 80-8094, October, 1979.

Hendee, WR and Rossi, RP: Quality Assurance forFluoroscopic X-ray Units and Associated Equipment. HEWPublications (FDA) 80-8095, October, 1979.

Hendee, WR and Rossi, RP: Quality Assurance forConventional Tomographic X-ray Units. HEW Publication(FDA) 80-8096, October, 1979.

McCrohan, JL, Showalts, CK, Burkhart, RL and Schuniam,FGD: The Status of Quality Assurance for ComputedTomography Systems. SPIE 419:145-156, 1983.

National Council on Radiation Protection andMeasurements: Quality Assurance for Diagnostic ImagingEquipment. NCRP, Bethesda, MD, 1988.

Nickoloff, EL: X-ray Quality Control Programs inEncyclopedia of Medical Devices and Instrumentation.Webster, JG (ed): John Wiley and Sons, Inc. 1988, Vol.4, pp. 2912-2929.

30