GH9800015

TECHNICAL REPORT, 1997

SAFETY ASSESSMENT AND QUALITY CONTROL OF MEDICAL X-RAY FACILITIES IN SOME HOSPITALS IN

E.O.DARKO AND D.F. CHARLES RADIATION PROTECTION BOARD GHANA ATOMIC ENERGY COMMISSION P. O. BOX 80 LEGON

29-39 a. TECHNICAL REPORT, 1997

SAFETY ASSESSMENT AND QUALITY CONTROL OF MEDICAL X-RAY FACILITIES IN SOME HOSPITALS IN GHANA

E. O. Darko and D. F. Charles Radiation Protection Board Ghana Atomic Energy Commission P. O. Box 80 Legon, .

ABSTRACT

Safety assessment and quality control measurements of diagnostic x-ray installations were earned out in five Hospitals in Ghana. The study was focused on the siting, design and construction of the buildings housing the x-ray units, assessment of safety systems and devices and measurements of the technical performance, and film processing conditions. The location, inadequacies in the design/construction, unavailability of relevant safety systems ar.d devices, violation of basic safety principles and poor performance of some of the x-ray faciliiies indicate the need to improve quality control programmes, safety culture and enforcement of regulatory standards in diagnostic x-ray examinations in Ghana. 1. INTRODUCTION

Medical application of x-rays constitute the greatest source of man-made radiation exposure in Ghana. It is estimated that x-rays in diagnostic examinations contributes about 90% of all man- made sources [1], Data collected between 1988-94 show that the mean annual collective effective dose due to x-ray examinations in Ghana is about 252 man mSv i.e. 0.014:Sv per capita per year [2]. The frequency of the x-ray examinations vary remarkably from one Hospital to the other.

Available statistics show that radiation risk factors have increased in recent times [3-5]. Poor image processing conditions, deficiencies in the performance of some of the x-ray machines have been some of the contributory factors leading to poor contrasts in x-ray photographs. Violation of basic safety principles and multiple x-ray examinations have also led to overexposure of both patients and the x-ray technicians in an attempt to improve image quality.

To institute controls and enforce regulatory standards in order to minimize doses to both patients and the x-ray worker, there is the need to ensure effective quality control programme, and adequate radiological protection and safety in the x-ray departments.

This report presents a survey conducted in five hospitals in Ghana. The survey focused on the safety in siting, design and construction of the x-ray departments and measurements of some technical parameters of the x-ray machine. This is with a view to assist in the improvement of radiological safety in the X-ray Departments of the Hospitals.

2. MATERIALS AND METHODS

2.1 Quality Control

Quality control measurements were carried out in five Hospitals in the Brong-Ahafo, Eastern, Volta and the Greater Accra Regions. The measured units consisted of conventional diagnostic x- ray units with bulky tables and chest stands. The generators were different models of Siemens, Toshiba and ERAF. The technical parameters and exposure measurements were performed with a radiation monitor MONITOR 4™ equipped with an ionization chamber, and Victoreen model 4000M+ multifunction meter.

Film processing conditions were tested using an RMI dual colour sensitometer X-Rite model 334 and RMI 331 B/W transmission densitometer. Films were developed according to the method used in the Hospitals. The films used in the Hospitals were mainly KODAK, MACO-x-ray, Valca and AGFA Curix.

2.2 Safety Assessment

Safety assessment was carried out with respect to the siting, structural shielding, adequacy of room space and availability of safety systems and devices. The assessment of the type and extent of barriers required to protect the workers and the general public depends on the output factors of the x-ray machine, and use and occupancy factors.

2.2.1 Siting

The location of the x-ray department was assessed with respect to its proximity to outpatient and emergency wards as well as the relative occupancies of adjacent areas to the x-ray room. The occupancy factor is the fraction of the treatment time for which a particular area is likely to be occupied.

The occupancy factors for primary barriers are designated thus:

T = 1 for the floor; T = 1/4 for the walls; and T < 1/4 for the ceiling.

For work areas such as offices, laboratories, shops, occupied areas in nearby buildings, living quarters, and so on, we assign T = 1 for full occupancy. Corridors, rest rooms, unattended parking lots, elevators with operators, etc are assigned T = 1/4 for partial occupancy. Waiting rooms, toilets, unattended elevators, pedestrian walks and vehicular traffic, etc. are assign occupancy factor of T = 1/16 for occassional occupancy [6].

2.2.2 Structural Shielding and Design

Ths integrity of the walls of an x-ray room and extent of other primary barriers depend on the output parameters of the x-ray machine being used. An ideal x-ray room has a minimum room space of 25m2 and workload of 50% for chest x-ray examinations, 30% for Abdomen, Pelvis and spine and 20% for skull and extremeties examinations [6,7].

Scattered radiation measurements were performed with the x-ray tube oriented in the horizontal and vertical directions, representing the most common types of examinations e.g. chest and abdomen respectively. Dose rates at different positions in the x-ray room and behind the doors and walls outside the x-ray room were measured using the radiation monitor MONITOR 4™.

2.2.3 Safety Systems and Devices

Safety systems such as warning signs, warning lights and interlocks as well as the safety devices used to protect patients, operators, radiologist and parents/people who help some patients were inspected. The safety devices include gondal shields, lead rubber gloves, lead aprons, lead glasses and radiation protection doors or lead protective barriers. 3. RESULTS AND DISCUSSIONS

Tables 1 and 2 show the number of radiological units and the reported number of common x-ray examinations in the sample hospitals. Three of the hospitals serve large communities within the various regions. In two of the hospitals, namely Manna Mission and Methodist Church hospitals, the x-ray units have not yet been installed. In the V. R. A. hospital, only the conventional x-ray unit is functioning. The fluroscopy and dental units are yet to be put into operation.

Quality control parameters measured to determine the performance of the x-ray units are provided in tables 4-6. The accuracy of the exposure parameters, namely, the reproducibility of the radiation exposure parameter, x-ray tube voltage and the exposure time partially meet the recommended limit of 5%, 10% and 15% respectively[8]. These show that the units are not performing consistently as required.

Film processing condition and range of film processing parameters are shown in tables 7-8. It should be noted that the temperatures of the processors (developer, fixer and washer) are significantly higher given rise to high thermal fogging of the films. The characteristic curves of film processing in some of the hospitals is shown in figure 1. The curves indicate clearly the differences in the performance of the processing parameters. Most of the processing conditions indicate a high base and fog, and low maximum optical density. These conditions results in poor image quality and consequently leading to overexposure of patients in an attempt to improve on the image quality through multiple x-ray examinations. The conditions may be improved by using high speed film-screen combinations and high quality film processing. The cost and benefit for such improved processing conditions would be tremencvus. Additionally, quality assurance measures should be established to maintain high level of quality.

The mean doses in adjacent areas around the x-ray rooms are provided in table 9. Most of the values measured are below the minimum detectable limit of 0.2(iSv/hr for the dose rate meter used, especially for V. R. A. hospital. This indicate the quality of construction of the walls of the x-ray room with respect to scatter radiation. Scatter radiations were detected at the main entrance to the x-ray room, the wall behind the chest stand, the radiographer's office and parts of the patients waiting area in some of the hospitals. These show that there are no lead doors and the structural shielding of the walls are inadequate. They can also be observed from the design of the various protective barriers given in table 10. From table 10, it can also be seen that with the exception of V. R. A. and Manna Mission hospitals, the windows of the main x-ray rooms are low level even though these rooms are located in high occupancy areas. Some of the hospitals do not also have adequate safety devices as exemplified in table 11. Figures 2-6 show the layout of the x-ray departments for the various hospitals. Some of the x-ray units are located within full occupancy in supervised areas with only that of the V. R. A. situated within an isolated area of the hospital complex. CONCLUSION

The safety assessment and quality control measurements revealed the need to establish and maintain an effective quality assurance programme in the x-ray departments of the hospitals. Basic Quality Assurance (QA) test devices such as densitometer, sensitometer radiation monitor, kVp meter and image quality test devices could be provided for routine QA programme. Additionally, conditions in the x-ray departments need to be improved with appropriate orientation of x-ray beam in order to reduce scatter radiation to occupied areas of the x-ray departments. These should be of priority when considering the cost and the benefit to improve image quality and reduce doses to patients and the occupational workers.

ACKNOWLEDGEMENT

The authors are very grateful to Mr Awudu Razark of the Radiation Protection Board for assistance during the surveys at the Hospitals. The authors would also like to extend their appreciation to tne Radiation Protection Board and the Hospitals involved for the support and hospitality.

REFERENCES

[1] Andam, A.A.B, et al; Occupational Radiation Monitoring and Quality Assurance in Hospital X-ray Department, Journal of U. S. T. Vol. No. 2 pp 79-85, (1990).

[2] Osei, E.K.; Occupational Radiation Exposure in Ghana, Journal of Radiation Protection Dosimetry, Vol. 71 No. 3 pp 207-214 (1997).

[3] ICRP 1990 Recommendations of the International Commission on Radiological Protection. Publication 60. (Oxford: Pergamon Press) Ann ICRP 21 (1-3) (1991).

[4] Servonaa A. et al, Quality Control and Patient Dose from X-ray Examinations in some hospitals in Estonia, Journal of Radiation Protection Dosimetry, Vol. 57 Nos 1-4, pp 297-300 (1995).

[5] National Academy of Sciences. Health Effects of Low Levels of Ionizing Radiation. BEIRV (Washington D. C. National Academy Press) (1990).

[6] IAEA Training Manual on the Safe use of Radiation Sources, IAEA, Vienna,(1992).

[7] IAEA Safety Series No. 14 on the Basic Requirements for Personnel Monitoring, IAEA, Vienna, (1980).

[8] Radiation Measurements Inc., (RMT). Quality Assurance in Radiology Table 1: Number of Radiological Units in the Sample Hospitals

Number Available Hospital

Conventional X-ray Fluoroscopy Dental E. P. Church 1 N/A N/A ()

V. R. A. 1 1 1 (Akosombo)

St. Theresa's 1 N/A N/A (Nkoranza)

Manna Mission 1 1 N/A (-)

Methodist Church N/A N/A N/A ()

Total 4 -V 1

**N/A- Not available Table 2: Number of Common X-ray Examinations in the Sample Hospitals in 1996

Number of Examinations Examination Adidome V. R. A. Nkoranza Wenchi Manna Mission Chest 395 3,640 457

Abdomen 42 728 55

Pelvis 25 494 37 N/A N/A

Skull 21 312 26

Others 38 416 -

Total 521 5,590 575

Table 3: Type of X-ray Equipment in the Sample Hospitals

Name of Type of X-ray Date of Model Number Country of Hospital Equipment Manufacture Origin E. P. Church Siemens N/A N/A Germany (Adidome) V. R. A. Siemens N/A 1158 815V 2072 Germany (Akosombo) Mobillet II St. Theresa's ERAF N/A FN 273263 Italy (Nkoranza ) Manna Mission Toshiba N/A DRX-660 Japan (Teshie) Rotanode Methodist N/A N/A N/A N/A Church (Wenchi)

N/A - Not Available Table 4: Techniques factors used for common x-ray examinations in the hospitals

Type of kVp Range mAs Range F. F. D. (cm) Workload Examination Range (mA-min/week) Range Chest PA 60-100 3-60 100-110 0.6-5.8

Lumber Spine 60-100 65-150 80-100 0.4-4.8 AP

Skull AP 60-90 60-100 80-100 0.3 - 4.0

Abdomen 60-80 30-40 80-100 0.3 - 5.8

Pelvis AP 60-90 70-100 80-100 0.82-1.32

Table 5: Output consistency of the r-ray units for the various hospitals

Hospital Type of X-ray Unit Coefficient of Variation (%) E. P. Church Siemens 13.2 (Adidome )

V. R. A. (Akosombo) Siemens 12.7

Manna Mission Toshiba N/A (Teshie-Nungua)

St. Theresa's (Nkoranza) ERAF 24.0

Methodist Church (Wenchi) N/A N/A

N/A - Not Applicable. The x-ray units have not been installed. Table 6: kVp and Timer accuracy for the X-ray units in the Hospitals

Hospital Mean % Deviation kVp Exposure tune E. P. Church (Adidome ) 8.1 19.2

V. R. A. (Akosombo) 7.4 18.4

Manna Mission (Teshie-Nungua) - -

St. Theresa's (Nkoranza) 9.2 15.0

Methodist Church (Wenchi) -

Table 7: Film processing conditions

Temperature (°C) Hospital Developer Fixer Washer E. P. Church (Adidome ) 28.0 27.7 28.1

V. R. A. (Akosombo) 25.1 24.3 24.7

St. Theresa's (Nkoranza) 27.9 27.5 27.8

Manna Mission - - - (Teshie-Nungua)

Methodist Church (Wenchi) Table 8: Range of film processing parameters in the sample hospitals

Parameter Film processing parameters Base + fog (OD) 0.20 - 0.55

Contrast (OD) 0.20 - 0.40

Maximum Density (OD) 2.55 - 3.23

Relative Speed 0.45 - 0.80

Table 9: Mean dose rates in adjacent areas around the x-ray rooms of the hospitals

Mean Dose Rate(ftv/hr) Hospital Behind Lead Enuance to Radiographer's Patients Main Screen Darkroom Office Waiting Entrance Area Door E. P. Church 10/4.2 0.4/O.2 10/6 O.2/0.4 6/3.8 (Adidome )

V. R. A. <0.2 <0.2 <0.2 J <0.2 <0.2 (Akosombo)

St. Theresa's 10/4.2 0.4/O.2 10/6 O.2/0.4 6/3.8 (Nkoranza)

Manna Mission - - - - (Teshie-Nungua)

Methodist Church - - - - - (Wenchi)

10 Table 10: Design of protective barriers for the hospitals

Barrier Design Hospital Radiation Walls of X-ray Shielded Cubicle or Windows Protection Room Mobile Screen of X-ray Door Room E. P. Church N/A Sancrete blocks, Mobile screen with Low-level (Adidome) 17.5m lead glass'windows

V. R. A. RPDlmPb Sancrete blocks Sancrete blocks High-level (Akosombo) lead-lined 22.5cm 22.5cm lead-lined

St. Theresa's N/A Sancreie blocks Sancrete blocks Low level (Nkoranza) 17cm 17.5cm

Manna Mission N/A Sancrete blocks Lead moveable High- (Teshie-Nungua) 22.5cm screen Level

* Methodist Church N/A N/A N/A N/A (Wenchi)

To be provided

RPD Radiation Protection Door

11 Table 11: Safety Systems and Devices available in the Sample Hospitals

Number Available Safety System/Device Adidome VRA Nkoranza Manna Mission Wenchi Warning Lights N/A N/A N/A * *

Warning Signs N/A N/A N/A * *

Lead Door N/A 1 N/A * *

Shielded Cubicle/ 1 I N/A Lead Moveable Screen

Gonadal Shields N/A 3 N/A * *

Lead Rubber Gloves N/A 4 pairs N/A * *

Lead Aprons 2 3 2 * *

Lead Glass Windows 1 1 N/A * *

Film Hatch N/A N/A N/A * *

Air Conditioners N/A N/A N/A * *

Extraction Fan N/A 1 N/A * *

N/A -> Not Available

To be Provided 12 Fig.1: Characteristic curves of film processing in some of the Hospitals 3.50E+00-

3.00E+00-

>, 2.50E+00- "55 © 2.00E+00 Q o 1.50E+00 *••-'

° 1.00E+00

5.00E-01 ^

O.OOE+00 i—i—i i i \ i i i i i—i—i—i—i—i i—i—i—i 11 13 15 17 19 21 8 10 12 14 16 18 20 Step Number

VRA Hospital EP Church Hospital St.Theresa Hospital 2.39m. HLW HLW

chest stand hatch split AC cutrol consols a lead view chest stand /window sheilded D radio graphic cubicle x-ray ' machine ro/radio 4.25m (MOBILETT) :-ray machine (KUN0GRAPH4-4) dental x-ray machine (DENTOUNE) main x-ray room lead-lined door sink

7.27m

corridor General office washroom patient's waiting room & window toilets Legend HLW - high level windows AC - air conditioner Fig. 2: Layout of the x-ray unit of the VRA Hospital, Akosombo. © H I H I h -» T LJLW chest stands, 1.42m \ 1 --3.45m 3.72m 2.94m I6 Office/Store o Huoro/Rad unit LLW Mobile x-ray unit 1 Corridor 1.05m LLW lead X-RAY glass Darkroom ROOM 2.94m 1.4m 1.2m <—> TV Monitor SC .•= j2.08m •3.72m- E5 Ji i i i i n H I 1 !• AC LLW

Legend: SC-Shielded cubicle or lead movable screen , LLW- Low level window AC-Air condition**, HLW-High level window

Figure 3 : Layout of Manna Mission Hospital X-ray Department Staff Residence

AC WF HLW AC -B- 3" Darkroom Film Chest Hatch Stand

Changing HLW room • Street toilet X-ray Lead 2S'-6" tube lass Store Office LLD Control HLW r room. -B3- •BB- -BB- P atients Waiting Are a V eranda

5.8m

Legend: LLD - Lead lined door HLW - High level window NB: Dimensions of X-ray Room AC - Aixccmditioaer;' EF - Extraction fan same -Oli^ ^^ WC - Water cbset (toilet)

Fig.4: PROPOSED LAYOUT OF WENCHI METHODIST HOSPITAL X ^ \Y DEPARTMENT (Not drawn to scale) T Darkroom C ) Office/Store LLW 2.36m- 2.38m

Shielded cubicle Cc?uch Chest Porch X-ray Stand View 1.1m window tube Health 3.9m Insurance Office 1.52m LLW 4.88m- 2.22m /vs. Patients Waiting. Corridor 1.

Wai^s

Fig. 5a : LAYOUT OF ST. THERESA'S HOSPITAL X-RAY DEPARTMENT Shielded cubicle Lead AC Control l~| glass console'-' Chest window [Couch stand Health 3.9m Insurance Q Office X-iay tube

HLW 6.68m- LLD I Patients > waiting A Changing room area Wards

Legend: HLW - High level window AC - Air conditioner EF - Fraction fan LLD - Lead lined door

Fig.Sb: MODIIIED LAYOUT OF ST. THERESA'S HOSPITAL X-RAY DEPARTMENT \% patient's waiting area Manual O Processor old sink

DARKROOM

curtain patient's waiting wooden panel area Cuupboard lead movable Main door screen chest 4.9m patient's stand waiting area > MAIN X'RAY ROOM

Radiographer's Table Cabinet Curtain Shelves

•6.08m-

Fig. 6a: LAYOUT OF ADIDOME EVANGELICAL PRESBY HOSPITAL X'RAY DEPARTMENT patient's waiting area AC Manual O Processor old sink Radiographer's Table DARKROOM

door patient's waiting door film sandrxete wall area hatch AC

lead-lined lead movable door screen chest 4.9m patient's stand waiting area > MAIN X'RAY ROOM I curtain cabinet cupboard

•6.08rn-

Fig.6b: MODIFIED UYOUT OF ADIDOME EVANGELICAL PRESBY HOSPITAL X'RAY DEPARTMENT