CDRH Maintenance Report
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Ziehm 7000 Plus Ziehm Compact Ziehm Vista Plus Ziehm Vario CDRH Maintenance Report
CDRH Maintenance Report 28143 - 01/2006
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CDRH Maintenance Report 28143 - 01/2006
CDRH Maintenance Report This is a master copy of Ziehm's CDRH Maintenance Report for the Ziehm 7000 Plus, Ziehm Compact, Ziehm Vista Plus and Ziehm Vario CArm. Make photocopies and safeguard it and for future use. You are required by the Food and Drug Administration (FDA) to perform the checks and inspections described in this document, at least every six months, in order to ensure that the x-ray system complies with federal regulations (specifically, the applicable sections of CFR 21, Subchapter J - Radiological Health).
Introduction
The equipment user is responsible for ensuring that the maintenance steps described in this procedure every six months. Failure to comply with this requirement relieves the Manufacturer and his agents of all responsibility in this matter.
Responsibilites
The equipment user is responsible for ensuring that only service technicians certified by the manufacturer perform the tests and adjustments described in this procedure. Service technicians are responsible for performing this procedure in the sequence shown. Please provide the following information:
Company information
Company Name: Phone Number: Address: C-Arm Model: C-Arm Serial Number: Location/Room Number: Name of Technician: Table 1
Company information
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Equipment
The following equipment and material is required to perform this procedure: − Digital multi meter (e.g., Fluke 8040A, Fluke 87 or Equivalent) − Dosimeter kit (Calibrated Radiation Dose Meter) − Beam center target, 40-400-T10 − Storage oscilloscope − Fluorescent cross, 44-14-538 RH090 − Vinyl lead sheets (3 mm lead blocker)
Reporting To FDA
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Once the following system compliance test are completed. You must complete the FDA 2579 HEW report and provide copy to the Facility, copy to the local State, copy to FDA, and one copy to the Manufacture. This must be completed with in 15 days of the install date. Form is available form the FDA.
Introduction Throughout this procedure you will be required to measure several equipment operating values and record your measurements. Checks or adjustments that require radiation exposure are marked with the radiation symbol displayed on the right, to alert you to follow all applicable safety codes and regulations.
CAUTION Make sure that you follow all safety rules regarding the use of radiationemitting equipment.
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Safety − Make all earth-lead connections provided by the manufacturer. For example, equipment metal panels may expose you to dangerous voltages, unless they are grounded. Therefore, ground metal panels. − Use a digital multi meter to check each ground lead connections. Measure from ground point to outside cover, to ensure that positive grounding has been achieved. − Follow all occupational safety laws and state codes that pertain to your installation site.
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− If there has been an accident, or if there are hazards which may result in an accident, immediately notify your supervisor. − Raise the C-Arm high enough to allow the C to rotate freely without interference from the C-Arm base or floor. Verify that the C-Arm is high enough and that the control locks work properly with the C-Profile in various positions.
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Necessary documentation
Verify that the following documents were delivered to the customer. Document
Documents Received?
Operating Instructions
Yes
No
Maintenance Instructions
Yes
No
Table 2
Necessary documents
If the customer cannot locate any of these documents, make arrangements to have the missing documents replaced immediately.
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Image intensifier
Inspect the image intensifier to determine if there are any mechanical faults (e.g., broken or missing covers). If there is a mechanical fault, write a description of the fault below and contact Ziehm Imaging, Inc.
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Labeling
Verify that the certification and warning labels are present and legible. Record the model number and serial number in the table below. If labels are required, contact Ziehm Imaging, Inc. Service department.
Check Labels
Refer to the product user manual for label location and identification. Inspect the C-Arm and verify that the certification, serial number, and model labels are present and legible. Record the model number and serial number in the box below.
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Certified Component Labels
Model No.
Serial No.
Pass/Fail
C-arm mobile stand X-ray control panel Image intensifier assembly X-ray generator Image system Laser LG Laser LC Table 3
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Label data
Check the dead man switch The purpose of this test is to verify that the system immediately stops emitting radiation once the hand switch or the foot switch are released. If either of the switches fails this test, contact Ziehm Imaging, Inc. Service Department.
6.1
Radiography At the mobile stand control panel, set exposure time to four seconds and kV to 40. • Press and release the hand switch and verify that radiation stops immediately after releasing the hand switch.
6.2
Fluoroscopy • At the mobile stand control panel, select Fluoroscopy mode. • Turn off Noise Reduction and Last Image Hold (LIH). • Press and the hand switch for a few seconds. Release and verify that radiation stops immediately after releasing the hand switch. • Repeat the last step using the foot switch. Record the results of this test in the box below. If radiation does not stop immediately, contact Ziehm Service. Dead man switch
Table 4
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Accept
Reject
Dead man switch
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Check radiation indicators
• Activate Radiography and verify that the radiation control indicator on the mobile stand control panel lights-up. • Activate Fluoroscopy and verify that the radiation control indicator on the mobile stand control panel lights-up, and that the yellow radiation light on the monitor cart lights-up. Radiation lights working?
Table 5
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Yes
No
Check radiation indicators
Check fluoroscopy time (see 21 CFR 1020.31 (a))
• Set manual fluoroscopy voltage to 40 kV. • Close the iris diaphragm and cover the tube assembly with a lead apron. • Switch on fluoroscopy. • Verify that the audible alarm sounds once the system has reached five minutes of fluoroscopy. • Press the Zero Min button to turn off the alarm. The time will continue to be displayed flash. • To turn off both the alarm and the LED, press and hold the Zero Min >2 Sec button. Fluoroscopy time in order?
Table 6
Yes
No
Check fluoroscopy time
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Check kV values
Fig. 1
Generator components
• Turn off the system and disconnect the power cord from the wall power supply. • Remove the tube head cover. • Set an oscilloscope to 2.0 volts on the DC scale (1 V = 10 kV). Connect the oscilloscope to TP OV and TP f (→ fig. 1, p. 2-8) or use a non Invasive kVp meter and place it in the beam above the generator following the manufactures instruction for measuring kVp. • Connect the system power cord to the wall power supply and turn on the system. • Select Radiographic exposure. • Press the manual kV button. • Set the timer to 0.4 seconds and kVp voltage to 50 kV. • Press the hand switch and make an exposure. • Observe the kV value displayed on the oscilloscope and write the value below. • Set the timer to 0.4 seconds and 110 kV. • Press the hand switch and make an exposure.
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• Observe the kV value displayed on the oscilloscope and write the value below. 50kVp
110kVp
Table 7
KV values
• If kV value displayed by the oscilloscope is > 10% of 50 kV or 110 kV, then the generator's U326 board must be adjusted. Adjusting the U326 Board • Set kV manually to 75 kVp. • Press the hand switch and make an exposure. Adjust P1 on the U326 board until the kV value displayed on the oscilloscope is 7.5 V or NonInvasive meter displays 75kVp. • Repeat all steps for checking the kV values described above. Note For more information, refer to U326 Board Service Calibration Instructions in the Service/Technical Manual for the model being tested.
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Check Tube Current
Tube current must be checked in each of the three fluoroscopic modes: −
Extremities
−
Head, Spinal Column, and Pelvis
− Thorax Rejection Criteria: − At 0.2 to 1.2 mA, reject if mA readings on multimeter and control panel display are different by 15% or greater. − At 1.3 to 8.0 mA, reject if mA readings in multimeter and control panel display are different by 10% or greater. • Turn off the system and disconnect the power cord from the wall power supply. • Remove the tube head cover. • Remove the mA bridge (→ fig. 1, p. 2-8) and insert a mAs multimeter probe in place of the jumper.
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• Adjust the mA multimeter to the lowest scale that displays a full 40 mAs. • Connect the system power cord to the wall power supply and turn on the system. • Select the Extremities mode, and press the hand switch or foot switch. • Observe the mA value displayed on the multimeter and compare to the value shown in the control panel display. If the difference between the values equals or exceeds the rejection criteria, then the U326 board must be re-calibrated. • Write the mA value displayed by the multimeter in the box below. • Repeat the last 4 steps for the other two fluoroscopic modes. kVp
Extremities
Pelvic
Thorax
LPD
50kVp 110kVp Table 8
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Tube current
Check Radiographic Tube Current Rejection Criteria: The mA value must be within 10% of the fixed 20 mA radiography value. • Turn off the system and disconnect the power cord from the wall power supply. • Remove the tube head cover. • Remove the mA bridge (→ fig. 1, p. 2-8) and insert a multimeter probe in place of the jumper. • Adjust the multimeter to the lowest scale that displays a full 40 mAs. • Connect the system power cord to the wall power supply and turn on the system. • Select 75 kVp and 3 seconds of exposure time. • Press the hand switch to release exposure. • Observe the mA value displayed by the multimeter and write this value into the box below.
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Radiography mA value
Table 9
Radiographic tube current
• If mA value displayed by the multimeter is > 10% of 20 mA, then the U326 board must be adjusted.
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Check Reproducibility
The purpose of the following test is to ensure that the system consistently produces a dose level that is within FDA tolerances, for every technique factor. This test consists of taking a set of four exposures, for each technique factor, within a sixty-minute time period. Make sure that: − the dosimeter is calibrated and working properly − measurements are made one-after-another − exposure technique are changed and reset after each measurement − all measurements are made within 60 minutes, from start to finish, and − that you do not exceed tube loading. Dosimeter Information Write the following information regarding your dosimeter into the box below. Dosimeter number: Manufacturer: Model Number: Serial Number: Chamber Serial Number: Date of last calibration: Table 10
Dosimeter information
Coefficient of variation For any specific combination of selected technique factors, the estimated coefficient of variation of radiation exposure must not exceed 0.045. The FDA has established the following: "All variable controls for technique factors shall be adjusted to alternate settings and reset to the test setting after each measurement. All values for percent line voltage
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regulation shall be within + 1 of the mean value for all measurements." (See 21 CFR 1020.31 (b) (2)). • Make sure that the available power supply meets the voltage requirements stated in Chapter 5 - Technical Data. • Place a dosimeter probe in the center of the x-ray path, 70 cm from the focal spot, as shown in Fig. 2.
Fig. 2
Dosimeter probe placement
• Select Radiographic Mode. Cover the intensifier input with 3 mm of lead blocker. • Set-up the x-ray system as follows: kV = 60, mA = 20, ms = 200. • Take an exposure. Write the resulting dose value into the box below, on line one, dose reading one, and reset the dose meter indicator to zero. • Repeat the previous step three times, writing the resulting dose values into line one of the table below. • Change kV to 90. • Take an exposure. Write the resulting dose value into the box below, on line two, dose reading one, and reset the dose meter indicator to zero. • Repeat the previous step until all 10 exposures have been taken, writing the resulting dose values into each of the 10 points on the table below.
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Dose [mR] Line
Table 11
kV
mA
ms
1
60 90
20 20
200 200
2
3
4
5
6
7
8
9
10
AVG
Coefficient of variation
Calculating the coefficient c for n individual measurements, the variation of the coefficient c is obtained from: S
= calculated standard deviation
X
= average value of all individual measurements
Xi
= measured value of the ith measurement
n
= number of individual measurements
∆ ∆
= difference 2
Table 12
= difference squared Calculating the Coefficient c
• Calculate the average: Add the four dose values and divide the sum by four.
X1 + X2 + X3 + X4 ------------------------------------------------= X ( Average ) n • Calculate the difference: Subtract each measured value from the average. Xi - X = ∆ (Difference) • Calculate the difference squared: Multiply the difference by itself. (Xi - X)2 = ∆2 Measurement
Table 13
Radiation Exposure
Average (X)
= Difference
Difference Squared
Calculated values
• Calculate the square root: Add the sum of the four differences squared and divide by 3. Write the result below. Sum = Table 14
Sum divided by 3 = Square root
S=
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• Calculate the variation coefficient: Divide the sum by the average value. Variation coefficient C = S/X = _____________/______________ C = _________________________________ ∆<0.045 Table 15
Accept
Reject
Variation coefficient
If the calculated value of the variation coefficient is greater than 0.045, determine the cause and take corrective action.
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Beam Quality Test Procedure
Fig. 3
Setting-up for beam quality test
Refer to 21 CRF 1020.30 (m) - Half Value Layer • Check the calibration of mA, kV, and mAs. • Select Radiography and set to 110 kVp. • Set time to 2.0 seconds to obtain 40 mAs. • Use the 6.0 cc chamber and collimate the beam so that it just covers the sensitive volume of the dose probe (→ fig. 3, p. 2-14).
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• Place a dose probe chamber in the center of the beam, 70 cm from the focal spot (→ fig. 3, p. 2-14). • Block input to the image intensifier with 3 mm of lead blocker (→ fig. 3, p. 2-14). • Initiate exposure. Determine the exposure value (R) and write this number into the first row of the Exposure Data column, in the table below. • Add filter material. Write the thickness of the added filter material into the next row of the AL Filtration column. • Determine the exposure value (R) and write this number into the next row of the Exposure Data column. • Repeat the two previous steps at four more times. Thickness (mm) of AL Filtration
Table 16
Exposure Data
Exposure data
• Plot the exposure data, as shown below.
Fig. 4
Exposure data plot
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− Under the first data point (600 in Fig. 4), place a data point that is onehalf the value. In this case, 300. − Draw a horizontal line from the data point to the curve. − Draw a vertical line from the point of this intersection to the horizontal axis (see Fig. 5).
Fig. 5
Plotting the half-value layer
This halving thickness is the half-value layer (HVL) of the useful x-ray beam. The HVL must not be less than 3.0 mm at 110 kVp. If the HVL is lower that 3.0m, determine the cause and take corrective action.
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Check Exposure Times • Connect an oscilloscope to test point F on the U54 board (→ fig. 1, p. 2-8) • Place 3 mm of lead in the path of the x-ray beam, to block radiation to the image intensifier. • Set the kV to 60 kV, and time to 0.4 seconds. • Press the hand switch to release radiation. • Read the exposure time on the oscilloscope (start from the beginning of a positive wave to the end of the negative wave that follows), and write the exposure time below.
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• Set the time to one second, make another exposure, and write the time below. Exposure time
0.4 sec._____________
1 sec.____________ms
Table 17
If the variation in exposure time is greater than 10%, determine the cause and take corrective action.
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Check Maximum Dose Rate During Fluoroscopy
Federal regulations (21 CFR 1020.32 (d) (1)) establish that fluoroscopic equipment with automatic dose rate control shall not be operable at any combination of tube potential and current which will result in an exposure rate in excess of 10 roentgens-per-minute at the point where the center of the useful beam enters the patient.
Federal Regulations
• Position a dosimeter probe as shown in Figure 9.
Fig. 6
Set-up of maximum dose rate test
• Select full image intensifier format. • Fully open the collimator. • Cover the image intensifier input with 3 mm of lead blocker. • Select Extremities and initiate fluoroscopy with the foot switch. Write the resulting dose rate in the box below.
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• Select Pelvic and initiate fluoroscopy with the foot switch. Write the resulting dose rate in the box below. • Select Thoracic and initiate fluoroscopy with the foot switch. Write the resulting dose rate in the box below. Extremities
Entrance dose rate = R____________________(min)
Pelvic
Entrance dose rate = R____________________(min)
Thoracic
Entrance dose rate = R____________________(min)
Table 18
Entrance dose rate values
Reject if entrance dose rate is greater than 9.9 R/min. • Write the model number and serial number of the dosimeter in the box below. Dosimeter Model No.: Dosimeter Serial No.: Table 19
Dosimeter data
• Answer the question in the following box. Did X-ray production cease immediately when the hand and/ or foot switch was released? Table 20
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Yes
X-ray production
Check the Central X-Ray Beam
Federal Regulation
Federal regulations (21 CRF 1020.31 (e) (1)) establish that the radiation field must be centered on the image receptor within a tolerance of less that 2% of the Source-to-Image-Distance (SID). The central x-ray is checked through the monitors. • Attach the beam alignment target (p/n 40-400-T 10) to the image intensifier. • Fully open both the slot collimator and iris diaphragm. • Select the full image intensifier format (i.e., no zoom). • Place the C-Arm in the Basic position, shown in Fig. 7.
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Fig. 7
C-Arm in the basic position
• Initiate fluoroscopy with the foot switch. • While watching the monitor, slowly close the iris until the edges of the iris are visible on the monitor. • Evaluate the position of the central beam as shown in Fig. 8. A = mid-point of the image intensifier input B = middle of the radiation field A = deviation of A to B • Write the actual deviation in the box below.
Fig. 8
Evaluating the central X-ray beam
• Place the C-Arm in the Left position, shown in Fig. 9, and repeat the previous 4 steps. • Write the actual deviation in the box below.
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Fig. 9
C-Arm in left position
• Place the C-Arm in the Left position, shown in Fig. 9, and repeat the previous steps again. • Write the actual deviation in the box below. Average Deviation
Max. Permissible
Actual Avg. Deviation
Basic Left Right
= 5.0 mm = 20.00 mm = 20.00 mm
________________mm ________________mm ________________mm
Table 21
Deviation data
Values are relative to the monitor. At the C-Arm, full image intensifier format is selected.
Note If actual deviations are larger than the amount permissible, make adjustments according to section 17.0.
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Adjusting Central X-Ray in Relation to the Image Intensifier • Place the C-Arm in the basic position. • Attach the beam center target to the image intensifier (part number 10-400-T 10). • Initiate fluoroscopy by pressing the foot switch. • Adjust the iris collimator to approximately 10 cm in diameter. • Manually reduce kV until the target's markings can be clearly seen.
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