Quality control of advanced nuclear medicine equipment in

Anchali Krisanachida

Department of Radiology, Faculty of Medicine, Chulalongkorn University, Thailand

INTRODUCTION

Nuclear medicine has been established in Thailand since early 1950's. Current status of nuclear medicine can be considered into twofold : service and training. Nuclear medicine service 14 Government Institutes carry on nuclear medicine service are classified as followings : A. University Hospital, Ministry of University Affairs 1. Siriraj Hospital, , Bangkok 2. Chulalongkorn University Hospital, Bangkok 3. Ramathibodi Hospital, Mahidol University, Bangkok 4. Chianmai Universty Hospital, Chiangmai 5. Prince of Songkhla University Hospital, Songkhla 6. Khon Kaen University Hospital, Khon Kaen B. Ministry of Public Health 1. National Cancer Institute, Bangkok 2. Rajavithee Hospital, Bangkok 3. Somdej Chao Phya Hospital, Bangkok C. Ministry of Defence 1. Pra Mongkut Klao Army Hospital, Bangkok 2. Somdej Pra Pinklao Navy Hospital, Bangkok 3. Bhumibol Adulyadej Air Force Hospital, Bangkok D. Bangkok Municipal Metropolitan 1. Vajira Hospital 2. General Hospital There are 5 private practice in nuclear medicine services located at various of Bangkok . EQUIPMENT

In 1991, 86 nuclear medicine equipments are used for in vivo and in vitro studies as followings: 21 Gamma cameras of 7 SPECT capability and 9 computers attachment

17 dose calibrators 12 single probe uptake systems 5 multi probe systems 14 rectilinear scanners

17 In vitro gamma counters Details of equipments are shown in Table 1.

TABしE1:NUCLEARMEDtCINEEQU塵PMENTAT14HOSPITALSINTHAILAND(1991)

RADIONUCLIDESANDINVESTIGATIONS

lnThailandin1988,110Ciof99Tc瓜wasusedforradionuclideirnaging

70Ciof1311forthyroidinvestigationsandtreatment

130mCi◎f201TCformyocardialperfusionimaging

110mCiof1251forradioimmunoassays

196 Imaging : Thyroid8,984 cases (40.49%) Bone4,232 cases (19.07%) Hepatobiliary4,084 cases (18.41%) Blood pool937 cases ( 4.37%) Total body904 cases ( 4.07%) Others3,019 cases (13.59% Treatment Thyroid4,206 cases In —vitro Thyroid149,728 cases non —thyroid132,523 tests

NUCLEAR MEDICINE TRAINING There are 3 levels of nuclear medicine training in Thailand A. Residency training course. Training programme for specialists in medical field were established in Thailand in 1969. In 1971, residency training in Radiology was established among other 13 residency training programmes. All programme require 3 year training . At that time there were 3 medical centres qualified for training in Radiology. Nuclear medicine training was parted by radiotherapy until 1987 which the training has been estsblished separately as Thai Board of Nuclear Medicine. Now there are 5 training centres in Thailand. B. Medical Physic course. School of Medical Physic was established in 1972 at Mahidol

University Bangkok which the author was the former Director of the School . This postgraduated M.Sc. 2 year course consists of lectures, practices, seminar, on —the —job —training in radiotherapy and nuclear medicine and thesis. The number of graduates are about 60 which 80 percent of these serve applied physics in radiotherapy while 10 percent serve nuclear medicine and radiation protection and the other 10 percent run their own business.

C. Technologist training. 2 levels of technologist training are 4 year course of B.Sc. degree in rediological technology and 2 year course of Certificate in Radiological Technology . The first stresses on theoretical and reserch work to serve the university hospital or institute with advanced technology . The latter serves the hospital in rural area and private clinic . Nuclear medicine is partly in radiological training.

NUCLEAR MEDICINE PERSONNELS Nuclear medicine clinicians, and physicists are mostly trained abroad from well —known centres in USA, UK or Australia for over twenty years ago . Rough figures of major personnels , full time, in 1990 is shown in Table II

197 TABLE II : NUCLEAR MEDICINE PERSONNELS IN THAILAND IN 1991

Most nuclear medicine specialists are concentrated in university hospitals with advanced nuclear medicine equipments. They carry on teachihg, clinical service and research works equally.

Quality Control of Nuclear Medicine Instruments in Thailand A quality control programme for nuclear medicine instrumentation has been establied for several years at some . A project extending to the national level was started by IAEA in 1983. The aim of the project is to improve current practices QC of instruments and procedures and to establish a national QC programme. A natinal project leader was appointed and an IAEA expert was assigned to assist. The project is concerned with scintillation cameras, rectilinear scanners, probe systems, radionuclide dose calibrators and gamma counters. Fifteen hospitals with nuclear medicine facilities in Thailand were included in the project.

PROJECT ORGANIZATION Initially, the project leader obtained from the IAEA various test phantoms and radioactive stan- dard sources required for QC tests. Chulalongkorn hospital was established as a pilot laboratory to familiarize with tests techniques and implemented operation and reference tests as described in IAEA TECDOC —317. Particular attention was given to the documentation, evaluation and follow —up of test results. Then, together with the IAEA expert, the project leader visited each hospital to assess its QC practices. The visits were then made every six months to follow up the recommendations made during the last visit, to continue training of local personnel and to carry out reference test with the test phantoms. As an extension of the project, overall performance was assessed in some departments using transmission phantoms : the IAEA simulated anatomic liver phantom and the College of American Pathologists simulated thyroid Phantom. Evaluation of the information concntrated mainly of the score of preceived targets in the images, that is, the number of true and false positive targets and of true and false negative targets detected. This project has also focused on the environmental needs of instruments particularly power—con- ditioning and air —conditioning and on problems associated with instrument malfunction and repair in- cooperated with on IAEA maintenance project. Two hospitals had already eatablished a full QC programme with record keeping and evaluation of test results before the national programme was started. Ten hospitals later established the QC pro- gramme at various levels. Hospitals with medical physicists, and well trained technologists showed the fully establishment while centres with technicians performed QC programme without interpretation. Two hospitals showed no interest and one, Neurological Hospital, ceased to service in nuclear medicine.

QUALITY CONTROL OF ADVANCED NUCLEAR MEDICINE INSTRUMENTS IN THAILAND

The first SPECT has been installed and used in September 1985 in Bangkok. The first test has been cart-id out by an IAEA expert together with the project leader and other staff on 20 March 1986 which covered Mechanical alignment and stability Detector head tilt during rotation Uniformity calibration and total performance Center of rotation offset calibration Pixel size calibration Lecture on SPECT and QC was also given to the department. In November 1987, an IAEA training course on "Computer applications in nuclear medicine imaging" has been organized in Bangkok using DEC and ADAC computers for practical works. In 1988, 2 SPECT were installed in Bangkok and the fourth was installed in 1989. It is expected by the end of 1991 there will be 7 SPECT in Thailand . Again, SPECT QC programme was carried out at various levels. Full programme of SPECT QC is carried out pilot laboratory while 2 centers can perform only uniformity calibration and the center with feirst SPECT showed limited understanding of QC programme . Plan for visits at hospitals with SPECT is quite complicated as it takes time to complete fully programme especially at the acceptance tests.

199 SOFTWARE PHANTOM In 1988, a set of clinical dynamic cardiac studies, software phantom was circulated to DEC, ADAC and GE computer users in Thailand for the purpose of quality control of analysis software. The softwere phantom of normal and abnormal of gated cardiac blood pool studies were transferred between system for the analysis of left ventricle ejection fraction(LVEF). The results obtained for 10 software phantoms using commercial and users development analysis softwere were similar in some phantoms but widely divergent in others. The other purpose of software phantom is used for the nuclear medicine training aids, the periodical check of the upgrade and also the current analysis soft- ware. This software phantom is available at some computer system for nuclear medicine imaging. It is hoped that the transfer of software phantom to other computer systems such as microdelta, Elscint and Toshiba should be successful in the near future.

SPECT TRAINING COURSE 4 Training courses of 2 weeks period had been arranged at this centre in 1990 to educate the new SPECT user. Training aids including software were supported by RPAH and POWH in Sydney from IAEA computer course. This course is planned for regular education in computer applications and computer QC every year.

PROJECT PROBLEMS Various problems had occurred since the former oroject until present. Those are A. Personnel. The lack of medical physicist at centres with advanced equipment causes the sooner deterioration of the preformance of the equipment. Furthermore, the use of equipment is very limited as their physical knowledge of computer and SPECT is not enough to implement including the quality control. B. Equiment. Various models of computer and SPECT in Thailand, such as GE, Siemens, Toshiba, Elscint, DEC, ADAC and microdelta cause their own problem and the lack of communication. This also cause difficulty in training the new users. Similar systems at different hospitals are Toshiba SPECTs and ADAC computers. Other common problem is the long period of malfunction equipment according to lack of service contract to maintain the equiment, the lack of stock of spare parts and the nonresponse of the service from local distributor.

RECOMMENDATIONS It is rcommended that the common factors which the Agency should consider are : 1. Establish the expert physicists familiar with the instrumentation and software to provide an in- dependent appraisal at acceptance testing and consultation of problems in each country. 2. Support on documentation. TECDOC 317 is well documented which SPECT chapter is still in draft form. This are long overdue since many SPECTs are available in this region. Furthermore, (NEMA) protocols for whole body imaging performance should be introduced as many new cameras

200 have been produced specifically for whole body imaging. The importance of this imaging mode is exemplified by the predominance of whole body skeletal imaging which form 19.07% of all nuclear medicine procedures in Thailand in 1988 and show slow annual increase. 3. Computer user group. Quantitative parameters of parametric images such as flood field uniformity and related parameters as shown in Table could be undertaken by computer user group for software development. Furthermore, the development of expert system for routine QC evaluation (Todd —Pokropek 1988, Slomka and Todd —Pokropek 1990) should be introduced. This is basically designed on the TECDOC —317 document and runs on a standard IBM microprocessor.

TABLE]1I PARAMETERS APPLIED TO QUANTIFICATION OF FLOOD FIELD

S I G = Standard deviation of pixel counts AVR = Mean count value

4. Intercomparison of the instrument performance especially SPECT systems using phantom i.e. Phelps and standardized protocol (Graham 1989) should be useful for the next period. Project leader should possess a set of phantoms for proper acceptance and reference tests and loan to other facilities in the country. Phantom to determine collimator hole angulation for rotating camera is quite useful (Busemann Sokole 1987). This phantom is now constructing at this hospital. 5. Public relations work. Newsletter containing variois informations of instruments, centres, com- puter data, hardware, software, development, bug and debug, clinical software, computer directory should be contributed and published for exchanging information and idea and for the usefulness of other users. 6. Regular education in computer applitions and related quality control is recommended at all levels as computer dependency increases still further and camera systems become more sophisticated . Detail of our training course on "Nuclear Medicine Imaging" for lecture topic and practical topic is attached in APPENDIX 1.

Quality is never an incident, it is always the effect of intelligent effort. APPENDIX 1

TRAINING COURSE "NUCLEAR MEDICINE IMAGING" ORGANIZED BY SECTION OF NUCLEAR MEDICINE DEPARTMENT OF RADIOLOGY CHULALONGKORN HOSPITAL

202 REFERENCES 1. AAPM (1982) Computer - aided scintillation camera acceptance testing, American Association of Physicists in Medicine Report No. 9, American Institute of Physics, New York 2. Busemann Sokole E (1987) Measurement of collimator hole angulation and camera head tilt for slant and parallel hole collimators used in SPECT. JMM28 : 1592-1598 3. Graham LS (1989) A quantitive quality control program for SPECT. JNM 30 : 851-852 4. Graham LS (1989) A rational quality assurance program for SPECT Instrumentation. In : Nuclear medicine annual. Baven Press, New York, 81-108 5. NEMA (1986) Performance measurements of scintillation cameras. Standard Publication NU -1-1986, National Electrical Manufacturers Association, Washington D. C. 6. Sharp P, Marshall I (1981) The usefulness of Indices measuring gamma camera non uniformity. PMB 26 149-153 7. Slomka P, Todd - Pokropek A (190) A general purpose micro - computer based quality assurance package desigbed to be used under an expert system shell. 5th World Congress, World Federation of Nuclesr Medicine and Biology, Montreal 8. Todd - Pokropek A. (1988) The design of the quality assurance package integrated into an expert sysrem. In : Hofer R, Bergman H(eds) Radioactive isotopes in clinical medicine and research. Schattauer, Stuttgart, New York. 469-478

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