- Email: [email protected]
Reject analysis: a pilot programme for image quality management
European Journal of Radiology, 12 ( 199
1) 1I l-l 16
Elsevier
EURRAD
171
00153
Reject analysis: a pilot programme for image quality management T.N. Arvanitis,
P.M. Parizel, H.R. Degryse and A.M.A. De Schepper
Department of Radiology and Medical Imaging. Antwerp University Hospital, Antwerp, Belgium
(Received 9 October
Key words: Quality assurance,
1990; accepted
image management;
27 December
1990)
Quality assurance,
film wastage
Abstract
The radiographic film wastage and the different parameters affecting this wastage were analysed for a 9-week period at a 600-bed University Hospital. An overall reject rate of 7.6% was found. The different reasons for rejection were evaluated, while retake rate, relation between working experience of the personnel, amount of rejected films and total film wastage in surface (m’), were registered and analysed.
Medical imaging provides information about the internal construction and derangements of the human body. In order to obtain this information it is necessary to produce an image. The correct interpretation of this image is a condition for further therapy planning. Hence the quality of that image plays an important role in the accuracy of the diagnostic process. Monitoring of the quality of the radiographic image is provided by the methods and procedures of Quality Assurance. The organization of a quality control programme includes the analysis of the radiographic image reject frequency. The reject analysis consists of a ‘pilot’ survey, with the help of which it becomes possible to identify the quality level of a medical imaging department [ 1,2]. The British Institute of Radiology gives the following definition for ‘Reject Analysis’: ‘Reject Analysis can be described as the critical evaluation of radiographs which are used as part of the imaging service but do not play a useful part in the diagnostic process’ [3]. In addition, the information provided by a reject analysis programme is fundamental for evaluating the Address for reprints: Prof. Dr. A.M.A. De Schepper, Dienst Radiologie en Medische Beeldvorming, Universitair Ziekenhuis Antwerpen, Wilrijkstraat 10, 2650 Edegem, Belgium. 0720-048X/91/$03.50
0 1991 Elsevier Science Publishers
B.V.
cost-effectiveness of a diagnostic imaging service and the radiation dose both to the examined patient and staff [4]. We have conducted a prospective survey over a 2month period regarding X-ray film wastage and the different parameters affecting this wastage in the Department of Medical Imaging of a 600-bed University Hospital. Materials and Methods The study was conducted at the Radiology and Medical Imaging Department of the Antwerp University Hospital over a period of nine weeks (7/5/90-7/7/90). During that period, all rejected films were collected from each individual X-ray room. For each rejected film the radiologists and radiographic technologists had to fill in a standarized information sheet, especially prepared for the needs of the study (see Fig. 1). The ‘reject rate’ was defined as the number of rejected films expressed as a percentage of the overall number of films used [ 1,5]. The percentage of radiographs, retaken due to an error, represented the ‘repeat’ or ‘retake’ rate* i3,6-81. * “The term ‘repeat’ is commonly used but since the intention is that the retaken radiograph should not repeat the error, the use of the term ‘retake’ is perhaps more adequate”. [3].
172
UNIVEX$X~~ITAL No..........
DEPARTMENTOF RADIOLCGY
____________________~~~~~~~~~~~~~~~~~~~ :RADIOGRAPHIC REJECT ANALYSIS INPUT DATA: ____________________~~~~~~~~~~~~~-~~~~~ Category
: I II XII
Processor : No of
Date ..I../..
123456
x-Ray Room :...........
Repeated Examination
Y/N
Notas:................................................ ................................................ ................................................ ................................................
Fig. 1. The standardized
information
We divided the working personnel in four different categories. The first category consisted of technologists with less than 6 months experience (n = 2); the second category was the group of technologists with an experience of more than 6 months and upto 1.5 years (n = 3); the third category included technologists with an experience of more than 1.5 years (n = 11); and the last category consisted of three selected residents working in the uroradiology and gastro-intestinal radiology sections of the department. The grouping was realized in order to analyse the relation between the amount of rejected films and the working experience of the staff. The reason for rejection is one of the parameters studied. Ten different categories of reasons for rejection were used: Overexposure, due to incorrect selection of exposure factors. Underexposure, due to incorrect selection of exposure factors. Positioning error (including wrong selection of field size, unacceptable or insufficient collimation etc.).
sheet used during the period of the study.
Faults, originated by malfunctions of the processing systems. Faults due to malfunctioning of equipment and instrumentation Patient motion (including cases where the collaboration with the patient was impossible). Clear films (we defined as ‘clear films’, these of which only the polyester base remained after processing). - Unused films (we defined as ‘unused films’, the nonprocessed wasted films). Good films (in this category we included films that had an acceptable quality but they were identified as being non-contributory to the diagnosis). Other reasons (i.e., rejections by video/laser imaging, double exposed films, black films, test films etc.). Finally, we measured the wasted film surface in m2 for the different film formats used. It is evident that measuring the surface of films rejected gives a better idea of the film material wastage. Meanwhile, the total cost by the rejections can be easily calculated. In the literature this methodology is proposed to obtain more correct results in a reject analysis programme [4,9].
173
Results
TABLE 2 Reasons
The analysis of the rejected films showed an overall reject rate of 7.6 y0 during the period of the study. From the 32850 films used in the department 2501 were rejected by the residents and radiographic technologists participating in the survey. In 59 cases (2.4%), the information form was not tilled in properly, so that the confidence level of the study can be assumed to be 97.6%. By analysing the rejects we calculated the retake rate, which was estimated to a level of 3.2% (the radiologic procedure was repeated for 1058 rejected films). We studied the different reject rates for each category group of personnel. In Table 1 the number of films rejected by each category group is presented. The percentage of films rejected per category group represents the ‘absolute category reject rate’, while the percentage of films rejected per person consists the ‘category reject rate corrected for group size’. The figures of the reject rate corrected for group size demonstrate that most of the rejects were caused by category 1 (35.6%), followed in descending order by the categories 4 (33.2%), 2 (20.6%) and 3 (10.6%). In Table 2 the absolute and relative frequency of reasons for rejection are presented. For a better assessment of the numerical values we regrouped the different reasons for rejection in larger sections. This allows a better estimation of the contribution of each reason to the overall reject rate. A fair amount of rejections is related to inappropriate use of exposure factors. Overexposure errors represent lSo/, of the rejections, while underexposure errors represent 10.32%. Incorrect positioning of the patient, errors by inappropriate or insufficient collimation, wrong selection of the field size etc., contribute to the total amount of rejected films for 11.64%. Malfunctioning of equipment or instrumentation
for rejection ._____
Reason for rejection Overexposure Underexposure Positioning error Processing fault Equipment fault Patient motion Video/laser imaging Clear film Unused film Good film Double-exposed film Black film Test film Others Total
No. of films
%
316 258 291 32 175 63 362 347 237 260 10 29 46 15
15.00 10.32 11.64 1.28 7.00 2.52 14.47 13.87 9.48 10.40 0.41 1.16 1.84 0.61
2501
100
played a significant role as a reason for rejection. Equipment faults were responsible for 7% film rejections, while the number of films rejected by malfunctioning of the processing systems reached only a level of 1.28%. A large amount of spoilt films refers to unproper handling of the radiographic films: 13.87:~ of the rejected films were clear films, while the percentage of unused films was estimated to 9.48 %. Additionally, 14.47 y0 of rejected films derived from video and laser imaging systems, which are widely used in modem medical imaging departments. Finally, a large number of good films (10.40%) were rejected. These reasons for rejection are presented graphically in Fig. 2. The waste for the different formats of films used is presented in table 3. Calculation of the total surface in m2 showed a wastage of 232.79 m* of film material. By comparing the different reject rates between the
TABLE 1 Rejected
films per category group Category size
Category size
(n)
(“/I
2 3 4
2 3 11 3
10.5 15.8 57.9 15.8
Total
19
Category
1
* Absolute category reject rate. ** Category reject rate corrected for group size.
No. of films rejected per category group 508 443 837 713 2501
3’, of films rejected per category group*
No. of films rejected per person
‘I0 of films rejected per person**
20.3 17.7 33.5 28.5
254 147.7 76.1 237.1
35.6 20.6 10.6 33.2
715.5
174
POSITIONING 11.64%
UNDEREXPOSURE 10.32%
PROCESSING 1.28% EQUIPMENT 7%
OVEREXPOSURE 15%
PATMOTIDN 2.52%
OTHER 4.02% CLEAR FILM 13.97%
\
~~~
VIDEO/LASER IMAGING 14.47% UNUSED FILM 9.49% GOOD FILM 10.4%
Period of control:7/5/90
- 7/7/90
ANTWERP UNIVERSITY HOSPITAL Fig. 2. Reject analysis project; total results by different reasons for rejection (%).
Discussion
TABLE 3 Radiographic
film wastage in surface (m’)
Film type 35 cm x 43 cm 35 cm x 35 cm 30 cm x 90 cm 30 cm x 40 cm 24 cm x 30 cm 28 cm x 43 cm 18cmx24cm lScmx40cm 15cmx30cm 10 cm x 10 cm Mammo (18 cm x 24 cm) CT (35 cm x 43 cm) M.R.I. (24 cm x 30 cm) Duplicating film Dental 6 in. x 12 in. 8 in. x 10 in. 24 cm x 24 cm Total
No.
Surface in mz
634 85 11 104 360 11 30 0 0 608 92 424 10 17 24 0 91
95.42 10.41 2.97 12.48 25.92 0.85 1.30 0.00 0.00 6.08 3.97 63.81 0.72 2.56 1.08 0.00 5.22
2501
232.79
examination rooms (see Fig. 3) the largest rate was found in the gastrointestinal radiology section (722 rejected films), in the thorax X-ray room (449 rejected films), in the section of Computed Tomography (401 rejected films) and in the X-ray suite where routine skeletal examinations and conventional neuroradiological procedures took place during the period of the study.
The information generated by a detailed analysis of rejected films represents an indicator of the quality level in a medical imaging department. The collected and interpreted data can provide information about the functioning of an imaging service. The first step to the success of a reject analysis is the preparation and structured organization of the programme. The type and the validity of data obtained depends on the planning of the analysis [6,10]. We presume that the planning of such a programme should be in such a way that the performance of the study is simple and understandable, while in the meantime detailed information can be obtained [ 11,121. The collaboration of the personnel is mandatory for the success of the whole procedure. When an analysis of this type is carried out it is inevitable that some anxiety exists amongst the working staff [ 131. In our department the response of the personnel, in planning and realizing the reject analysis programme was very good. The special data form was filled in properly by all the members of the working staff, so that we had an excellent confidence level (97.6%). We reviewed the final results with the radiologists, residents and radiographic technologists of our department; during the period of the project, the staff members of the department, who were not directly involved, were informed of any preliminary results. The reject rate can be estimated as acceptable. Our
175
GASTRO EXAMINATIONS PULMO (THORAX) CON”.NEURORADlOL&: TRAUMATO (CONV. RX) PRESTILIX (CONV.RX) MAMMOGRAPHY URORADIOLOGY PHILIPS (CONV.RX) WARD RADIOGRAPHY DUPLICATIONS D.S.A. STRATOMATIC (TOMO) CON.ANGIOGRAPHY M.R.I. OUTPATIENT PROTOCOLS C.T. PROTOCOLS
i Total rejebted films $2501
NOT INDICATED 200
400
600
800
1000
ANTWERP UNWERSITY HOSPITAL Fig. 3. Reject analysis project. Reject rates by examination
results are similar to the results of other studies, where the reject rate ranged from 2% up to 13% [6,8,9,13]. However, it is difficult to decide what an optimum reject rate should be. The assessment for this reject rate is based on the tolerance limits suggested in the literature [4,14]. Specifically, a reject rate ranged between lo-12% is accepted for diagnostic imaging departments, where no quality assurance programme exists [ 151. Furthermore, the ‘retake rate’ (3.2%) can be considered to be relatively low. Concerning the reasons for rejection we have to emphasize a few specific points. The results of the exposure errors and imaging technique errors (positioning, selection of field size, collimation etc.) are proportional to those from several other studies [6,10,16]. The correct use of the tilm/intensifying screen in relation with the appropriate selection of the operating imaging system can reduce the rejects occurring by exposure factors. The rejects caused by positioning and radiographic technique faults can be reduced by training and individual improving efforts by the members of the staff. The high reject rates due to unproper handling of the radiographic film indicate the need for a continuous training of the working personnel. In a university medical imaging department, where a large turnover of radiographic technologists and residents exists, these problems are expected and contribute to an increase of film waste.
room (period of control: 7/5/90-7/7/90.
Overall, rejects due to insufficient functioning of the equipment (X-ray generators, timers, automatic exposure systems, grids etc.) do not play a significant role in the total reject rate [ 7,171. The high percentage of equipment faults in our survey can be explained by the fact that during the study several mechanical and electrical problems occurred in the generator and fluoroscopic camera of the gastro-intestinal X-ray suite, as well as to the film transportation system of the automatic thorax X-ray film rapid changer. The category reject rates indicate the relation between the working experience of the personnel and the amount of film wasted. It is expected that the radiographic technologists with less working experience have higher reject rates as compared to more experienced technologists with more working experience. The importance of correcting the percentages for the group size is obvious. The high reject rate for the fourth category can be explained by the frequent equipment problems during the survey, by the more complex nature of the contrast studies and by the fact that most examinations are carried out by residents in training. It is inevitable that in a diagnostic imaging department images of no diagnostic value can be produced, causing radiographic film wastage. Nevertheless, a Reject Analysis Programme assesses the incidence and identifies the causes of this film wastage. In t.hat way, it enables us to determine the quality level of a medical
176
imaging department. An extended application of such programmes in several hospitals can increase the costeffectiveness of the radiology and medical imaging departments, meanwhile decreasing useless irradiation of patients and working personnel. Comparison of different results helps the introduction and organization of a standardized quality assurance system. References 1. Lame1 DA et al. The correlated lecture laboratory series in diagnostic radiological physics, HHS publication FDA 81-8150, U.S. Department of Health and Human Services, Washington DC, 1981. 2. Watkinson S, Moores BM, Hill SJ. Reject analysis: its role in quality assurance. Radiography 1984: 50: 189-194. 3. British Institute of Radiology. Assurance of quality in diagnostic X-ray department, W & G Baird Ltd. London: Greystone Press, 1988. 4. Roberts DP, Smith NL. Radiographic imaging: a practical approach. London: Churchill Livingstone, 1988. 5. Trout ED, Jacobson G, Moore RT, Shoub EP. Analysis of the rejection rate of chest radiographs obtained during the coal mine ‘black lung’ program. Radiology, 1975; 109: 25-27. 6. Mazzafero RJ, Balter S, Janower ML. The incidence and causes of repeated radiographic examinations in a community hospital. Radiology 1974: 112: 71-72.
7. Berry RJ, Oliver R. Spoilt films in X-ray departments and radiation exposure to the public from medical radiology. Correspondence, Br J Radiol, 1976; 49: 475-476. 8. McKinlay A, McCauley B. Spoilt films in X-ray departments. Correspondence, Br J Radiol, 1977; 50: 233-234. 9. Bourne D. Repeats : an aspect of departmental management. Radiography 1969; 35: 257-261. 10. Kraeger JA, Christianson GA. Survey results of the use of X-rays in the healing arts specialities in North Dakota. Radio1 Technol 1970; 42: 161-174. 11. Harvey MJ, McClellan M. The Proceedings of the first workshop for radiographers in quality assurance. London: Scientific ERA Publications, 1981. 12. World Health Organization. Quality assurance in diagnostic radiology. Geneva: WHO Publications, 1982. 13. Mustafa AA, Vasisht CM, Sumanasekara SJ. Analysis of wasted X-ray films: experience in two Kuwait hospitals. Br J Radio1 1987; 60: 513-515. 14. Hospital Physicist’s Association, Quality Assurance Mesurments in Diagnostic Radiology. London: CRS Publication 29, HPA, 1979. 15. Gothlin JH, Alders B. Analysis of an image quality assurance program. Eur J Radio1 1985; 5: 228-230. 16. Belleti S, Gallini R, Guigni U. Analisi delle cause di scarto di pellicole radiogratiche in radiodiagnostica. Radio1 Med (Torino), 1984; 70. 46-49. 17. Gadeholt G, Geitung JT, Giithlin JH, Asp T. Continuing rejectrepeat analysis program. Em J Radio1 1989; 9: 137-141.
1) 1I l-l 16
Elsevier
EURRAD
171
00153
Reject analysis: a pilot programme for image quality management T.N. Arvanitis,
P.M. Parizel, H.R. Degryse and A.M.A. De Schepper
Department of Radiology and Medical Imaging. Antwerp University Hospital, Antwerp, Belgium
(Received 9 October
Key words: Quality assurance,
1990; accepted
image management;
27 December
1990)
Quality assurance,
film wastage
Abstract
The radiographic film wastage and the different parameters affecting this wastage were analysed for a 9-week period at a 600-bed University Hospital. An overall reject rate of 7.6% was found. The different reasons for rejection were evaluated, while retake rate, relation between working experience of the personnel, amount of rejected films and total film wastage in surface (m’), were registered and analysed.
Medical imaging provides information about the internal construction and derangements of the human body. In order to obtain this information it is necessary to produce an image. The correct interpretation of this image is a condition for further therapy planning. Hence the quality of that image plays an important role in the accuracy of the diagnostic process. Monitoring of the quality of the radiographic image is provided by the methods and procedures of Quality Assurance. The organization of a quality control programme includes the analysis of the radiographic image reject frequency. The reject analysis consists of a ‘pilot’ survey, with the help of which it becomes possible to identify the quality level of a medical imaging department [ 1,2]. The British Institute of Radiology gives the following definition for ‘Reject Analysis’: ‘Reject Analysis can be described as the critical evaluation of radiographs which are used as part of the imaging service but do not play a useful part in the diagnostic process’ [3]. In addition, the information provided by a reject analysis programme is fundamental for evaluating the Address for reprints: Prof. Dr. A.M.A. De Schepper, Dienst Radiologie en Medische Beeldvorming, Universitair Ziekenhuis Antwerpen, Wilrijkstraat 10, 2650 Edegem, Belgium. 0720-048X/91/$03.50
0 1991 Elsevier Science Publishers
B.V.
cost-effectiveness of a diagnostic imaging service and the radiation dose both to the examined patient and staff [4]. We have conducted a prospective survey over a 2month period regarding X-ray film wastage and the different parameters affecting this wastage in the Department of Medical Imaging of a 600-bed University Hospital. Materials and Methods The study was conducted at the Radiology and Medical Imaging Department of the Antwerp University Hospital over a period of nine weeks (7/5/90-7/7/90). During that period, all rejected films were collected from each individual X-ray room. For each rejected film the radiologists and radiographic technologists had to fill in a standarized information sheet, especially prepared for the needs of the study (see Fig. 1). The ‘reject rate’ was defined as the number of rejected films expressed as a percentage of the overall number of films used [ 1,5]. The percentage of radiographs, retaken due to an error, represented the ‘repeat’ or ‘retake’ rate* i3,6-81. * “The term ‘repeat’ is commonly used but since the intention is that the retaken radiograph should not repeat the error, the use of the term ‘retake’ is perhaps more adequate”. [3].
172
UNIVEX$X~~ITAL No..........
DEPARTMENTOF RADIOLCGY
____________________~~~~~~~~~~~~~~~~~~~ :RADIOGRAPHIC REJECT ANALYSIS INPUT DATA: ____________________~~~~~~~~~~~~~-~~~~~ Category
: I II XII
Processor : No of
Date ..I../..
123456
x-Ray Room :...........
Repeated Examination
Y/N
Notas:................................................ ................................................ ................................................ ................................................
Fig. 1. The standardized
information
We divided the working personnel in four different categories. The first category consisted of technologists with less than 6 months experience (n = 2); the second category was the group of technologists with an experience of more than 6 months and upto 1.5 years (n = 3); the third category included technologists with an experience of more than 1.5 years (n = 11); and the last category consisted of three selected residents working in the uroradiology and gastro-intestinal radiology sections of the department. The grouping was realized in order to analyse the relation between the amount of rejected films and the working experience of the staff. The reason for rejection is one of the parameters studied. Ten different categories of reasons for rejection were used: Overexposure, due to incorrect selection of exposure factors. Underexposure, due to incorrect selection of exposure factors. Positioning error (including wrong selection of field size, unacceptable or insufficient collimation etc.).
sheet used during the period of the study.
Faults, originated by malfunctions of the processing systems. Faults due to malfunctioning of equipment and instrumentation Patient motion (including cases where the collaboration with the patient was impossible). Clear films (we defined as ‘clear films’, these of which only the polyester base remained after processing). - Unused films (we defined as ‘unused films’, the nonprocessed wasted films). Good films (in this category we included films that had an acceptable quality but they were identified as being non-contributory to the diagnosis). Other reasons (i.e., rejections by video/laser imaging, double exposed films, black films, test films etc.). Finally, we measured the wasted film surface in m2 for the different film formats used. It is evident that measuring the surface of films rejected gives a better idea of the film material wastage. Meanwhile, the total cost by the rejections can be easily calculated. In the literature this methodology is proposed to obtain more correct results in a reject analysis programme [4,9].
173
Results
TABLE 2 Reasons
The analysis of the rejected films showed an overall reject rate of 7.6 y0 during the period of the study. From the 32850 films used in the department 2501 were rejected by the residents and radiographic technologists participating in the survey. In 59 cases (2.4%), the information form was not tilled in properly, so that the confidence level of the study can be assumed to be 97.6%. By analysing the rejects we calculated the retake rate, which was estimated to a level of 3.2% (the radiologic procedure was repeated for 1058 rejected films). We studied the different reject rates for each category group of personnel. In Table 1 the number of films rejected by each category group is presented. The percentage of films rejected per category group represents the ‘absolute category reject rate’, while the percentage of films rejected per person consists the ‘category reject rate corrected for group size’. The figures of the reject rate corrected for group size demonstrate that most of the rejects were caused by category 1 (35.6%), followed in descending order by the categories 4 (33.2%), 2 (20.6%) and 3 (10.6%). In Table 2 the absolute and relative frequency of reasons for rejection are presented. For a better assessment of the numerical values we regrouped the different reasons for rejection in larger sections. This allows a better estimation of the contribution of each reason to the overall reject rate. A fair amount of rejections is related to inappropriate use of exposure factors. Overexposure errors represent lSo/, of the rejections, while underexposure errors represent 10.32%. Incorrect positioning of the patient, errors by inappropriate or insufficient collimation, wrong selection of the field size etc., contribute to the total amount of rejected films for 11.64%. Malfunctioning of equipment or instrumentation
for rejection ._____
Reason for rejection Overexposure Underexposure Positioning error Processing fault Equipment fault Patient motion Video/laser imaging Clear film Unused film Good film Double-exposed film Black film Test film Others Total
No. of films
%
316 258 291 32 175 63 362 347 237 260 10 29 46 15
15.00 10.32 11.64 1.28 7.00 2.52 14.47 13.87 9.48 10.40 0.41 1.16 1.84 0.61
2501
100
played a significant role as a reason for rejection. Equipment faults were responsible for 7% film rejections, while the number of films rejected by malfunctioning of the processing systems reached only a level of 1.28%. A large amount of spoilt films refers to unproper handling of the radiographic films: 13.87:~ of the rejected films were clear films, while the percentage of unused films was estimated to 9.48 %. Additionally, 14.47 y0 of rejected films derived from video and laser imaging systems, which are widely used in modem medical imaging departments. Finally, a large number of good films (10.40%) were rejected. These reasons for rejection are presented graphically in Fig. 2. The waste for the different formats of films used is presented in table 3. Calculation of the total surface in m2 showed a wastage of 232.79 m* of film material. By comparing the different reject rates between the
TABLE 1 Rejected
films per category group Category size
Category size
(n)
(“/I
2 3 4
2 3 11 3
10.5 15.8 57.9 15.8
Total
19
Category
1
* Absolute category reject rate. ** Category reject rate corrected for group size.
No. of films rejected per category group 508 443 837 713 2501
3’, of films rejected per category group*
No. of films rejected per person
‘I0 of films rejected per person**
20.3 17.7 33.5 28.5
254 147.7 76.1 237.1
35.6 20.6 10.6 33.2
715.5
174
POSITIONING 11.64%
UNDEREXPOSURE 10.32%
PROCESSING 1.28% EQUIPMENT 7%
OVEREXPOSURE 15%
PATMOTIDN 2.52%
OTHER 4.02% CLEAR FILM 13.97%
\
~~~
VIDEO/LASER IMAGING 14.47% UNUSED FILM 9.49% GOOD FILM 10.4%
Period of control:7/5/90
- 7/7/90
ANTWERP UNIVERSITY HOSPITAL Fig. 2. Reject analysis project; total results by different reasons for rejection (%).
Discussion
TABLE 3 Radiographic
film wastage in surface (m’)
Film type 35 cm x 43 cm 35 cm x 35 cm 30 cm x 90 cm 30 cm x 40 cm 24 cm x 30 cm 28 cm x 43 cm 18cmx24cm lScmx40cm 15cmx30cm 10 cm x 10 cm Mammo (18 cm x 24 cm) CT (35 cm x 43 cm) M.R.I. (24 cm x 30 cm) Duplicating film Dental 6 in. x 12 in. 8 in. x 10 in. 24 cm x 24 cm Total
No.
Surface in mz
634 85 11 104 360 11 30 0 0 608 92 424 10 17 24 0 91
95.42 10.41 2.97 12.48 25.92 0.85 1.30 0.00 0.00 6.08 3.97 63.81 0.72 2.56 1.08 0.00 5.22
2501
232.79
examination rooms (see Fig. 3) the largest rate was found in the gastrointestinal radiology section (722 rejected films), in the thorax X-ray room (449 rejected films), in the section of Computed Tomography (401 rejected films) and in the X-ray suite where routine skeletal examinations and conventional neuroradiological procedures took place during the period of the study.
The information generated by a detailed analysis of rejected films represents an indicator of the quality level in a medical imaging department. The collected and interpreted data can provide information about the functioning of an imaging service. The first step to the success of a reject analysis is the preparation and structured organization of the programme. The type and the validity of data obtained depends on the planning of the analysis [6,10]. We presume that the planning of such a programme should be in such a way that the performance of the study is simple and understandable, while in the meantime detailed information can be obtained [ 11,121. The collaboration of the personnel is mandatory for the success of the whole procedure. When an analysis of this type is carried out it is inevitable that some anxiety exists amongst the working staff [ 131. In our department the response of the personnel, in planning and realizing the reject analysis programme was very good. The special data form was filled in properly by all the members of the working staff, so that we had an excellent confidence level (97.6%). We reviewed the final results with the radiologists, residents and radiographic technologists of our department; during the period of the project, the staff members of the department, who were not directly involved, were informed of any preliminary results. The reject rate can be estimated as acceptable. Our
175
GASTRO EXAMINATIONS PULMO (THORAX) CON”.NEURORADlOL&: TRAUMATO (CONV. RX) PRESTILIX (CONV.RX) MAMMOGRAPHY URORADIOLOGY PHILIPS (CONV.RX) WARD RADIOGRAPHY DUPLICATIONS D.S.A. STRATOMATIC (TOMO) CON.ANGIOGRAPHY M.R.I. OUTPATIENT PROTOCOLS C.T. PROTOCOLS
i Total rejebted films $2501
NOT INDICATED 200
400
600
800
1000
ANTWERP UNWERSITY HOSPITAL Fig. 3. Reject analysis project. Reject rates by examination
results are similar to the results of other studies, where the reject rate ranged from 2% up to 13% [6,8,9,13]. However, it is difficult to decide what an optimum reject rate should be. The assessment for this reject rate is based on the tolerance limits suggested in the literature [4,14]. Specifically, a reject rate ranged between lo-12% is accepted for diagnostic imaging departments, where no quality assurance programme exists [ 151. Furthermore, the ‘retake rate’ (3.2%) can be considered to be relatively low. Concerning the reasons for rejection we have to emphasize a few specific points. The results of the exposure errors and imaging technique errors (positioning, selection of field size, collimation etc.) are proportional to those from several other studies [6,10,16]. The correct use of the tilm/intensifying screen in relation with the appropriate selection of the operating imaging system can reduce the rejects occurring by exposure factors. The rejects caused by positioning and radiographic technique faults can be reduced by training and individual improving efforts by the members of the staff. The high reject rates due to unproper handling of the radiographic film indicate the need for a continuous training of the working personnel. In a university medical imaging department, where a large turnover of radiographic technologists and residents exists, these problems are expected and contribute to an increase of film waste.
room (period of control: 7/5/90-7/7/90.
Overall, rejects due to insufficient functioning of the equipment (X-ray generators, timers, automatic exposure systems, grids etc.) do not play a significant role in the total reject rate [ 7,171. The high percentage of equipment faults in our survey can be explained by the fact that during the study several mechanical and electrical problems occurred in the generator and fluoroscopic camera of the gastro-intestinal X-ray suite, as well as to the film transportation system of the automatic thorax X-ray film rapid changer. The category reject rates indicate the relation between the working experience of the personnel and the amount of film wasted. It is expected that the radiographic technologists with less working experience have higher reject rates as compared to more experienced technologists with more working experience. The importance of correcting the percentages for the group size is obvious. The high reject rate for the fourth category can be explained by the frequent equipment problems during the survey, by the more complex nature of the contrast studies and by the fact that most examinations are carried out by residents in training. It is inevitable that in a diagnostic imaging department images of no diagnostic value can be produced, causing radiographic film wastage. Nevertheless, a Reject Analysis Programme assesses the incidence and identifies the causes of this film wastage. In t.hat way, it enables us to determine the quality level of a medical
176
imaging department. An extended application of such programmes in several hospitals can increase the costeffectiveness of the radiology and medical imaging departments, meanwhile decreasing useless irradiation of patients and working personnel. Comparison of different results helps the introduction and organization of a standardized quality assurance system. References 1. Lame1 DA et al. The correlated lecture laboratory series in diagnostic radiological physics, HHS publication FDA 81-8150, U.S. Department of Health and Human Services, Washington DC, 1981. 2. Watkinson S, Moores BM, Hill SJ. Reject analysis: its role in quality assurance. Radiography 1984: 50: 189-194. 3. British Institute of Radiology. Assurance of quality in diagnostic X-ray department, W & G Baird Ltd. London: Greystone Press, 1988. 4. Roberts DP, Smith NL. Radiographic imaging: a practical approach. London: Churchill Livingstone, 1988. 5. Trout ED, Jacobson G, Moore RT, Shoub EP. Analysis of the rejection rate of chest radiographs obtained during the coal mine ‘black lung’ program. Radiology, 1975; 109: 25-27. 6. Mazzafero RJ, Balter S, Janower ML. The incidence and causes of repeated radiographic examinations in a community hospital. Radiology 1974: 112: 71-72.
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