USA Instruments, Inc.
PROFILE 7000
PHASED ARRAY VOLUME NECK COIL
Service Manual
Part No. 780007
Rev. A
USA Instruments, Inc. Phased Array Volume Neck Coil Service Manual
TABLE OF CONTENTS
Introduction
How the Coil Operates ....................................................................................................................... 3
Compatibility ..................................................................................................................................... 4
Coil Specifications ............................................................................................................................. 4
Related Documents ............................................................................................................................ 4
Setup and Calibration
Shipping List ..................................................................................................................................... 5
Installing the Coil ............................................................................................................................... 5
Quality Assurance .............................................................................................................................. 6
Replacement and Maintenance
Checking the Protection Pin Diodes and Output Cable with DMM ....................................................... 9
Field Replacement Unit List ...............................................................................................................10
Replacing of External Cable ..............................................................................................................11
Replacing the Anterior Bridge Assembly .............................................................................................11
Coil Care ..........................................................................................................................................12
Rev. A (9/99) Page 2 of 12
USA Instruments, Inc. Phased Array Volume Neck Coil Service Manual
INTRODUCTION
1. How the Coil Operates The block diagram of the Phased Array Volume Neck Coil is shown in
Figure 1. The Phased Array Volume Neck Coil is a receive-only coil designed
to give optimum signal to noise and uniform coverage of the neck region.
The coil consists of two elements: (1) a loop coil and (2) a saddle coil. The
coil has a split-top configuration which enables the scanning of patients
with different neck sizes (fits 98 percent of subject population) and patients
suffering from claustrophobia. The split-top design also facilitates easier
handling and positioning for the user.
Saddle Feeding
Loop Feeding
Saddle Trap Loop Trap
Figure 1: Block diagram of the coil.
For 1.5T Coil
Passive Blocking
Circuit
Solenoid Coil
A5 B5
A3 B3
Cable Trap Passive Blocking
Circuit
Bendix 30 PIN
Saddle Coil
Connector
Active Blocking
Circuit
For 1.0T Coil
Passive Blocking
Circuit
Solenoid Coil
A4 A5
B4 B5
A2 A3
B2 B3
Cable Trap Passive Blocking
Circuit
Bendix 30 PIN
Saddle Coil
Connector
Active Blocking
Circuit
Figure 2: Block diagram of the circuit layout.
Rev. A (9/99) Page 3 of 12
USA Instruments, Inc. Phased Array Volume Neck Coil Service Manual
INTRODUCTION (continued)
The Phased Array Volume Neck Coil is a receive-only coil. The coil is
actively decoupled from the RF transmit coil during transmit by means of a
RF choking circuit. The choking circuit elements are switched on and off by
pin diodes. During body coil transmission, the pin diodes are turned on with
a forward bias DC source (250mA) provided by the MR system. When the
pin diodes are turned on, each of the RF choking elements becomes very
high in impedance (typically above 2 kilo-ohm). These high impedance
elements in the coil segregate the coil circuitry into several isolated electrical
segments, preventing any current flow in the coil circuit. A 30 pin Bendix
connector is used to mate the coil with the systems phased array port.
2. Compatibility The Phased Array Volume Neck Coil (GE Part Number E8800PJ) is
compatible with the Signa HorizonTM 1.5T system.
The Phased Array Volume Neck Coil (GE Part Number E8800PK) is
compatible with the Signa HorizonTM 1.0T system.
3. Coil Specifications
Parameter Characteristics
Coil Design phased array, receive-only coil
Tuned Frequency 63.86 MHz (factory set) for 1.5T; 42.68 MHz (factory set) for 1.0T
Optimum FOV 28cm
Table 1: Coil specifications.
Transport and Storage Operating Conditions
Barometric Pressure 645mm Hg to 795mm Hg
20% to 95% 45% to 75%
Humidity
non-condensing non-condensing
Temperature -15 C° to 55 C° 15 C° to 35 C°
Storage Space
19" (L) x 17" (W) x 16" (H)
Requirements
Table 2: Environmental conditions.
4. Related Documents Operators Guide (USAI Part Number 770013 for 1.5T, USAI Part Number
770014 for 1.0T).
MR System Guide (GE Part Number 2124201-3 for Signa 5.X Service
Methods, GE Part Number 2160623-3 for Signa 8.X Service Methods).
Rev. A (9/99) Page 4 of 12
USA Instruments, Inc. Phased Array Volume Neck Coil Service Manual
SETUP AND CALIBRATION
1. Shipping List
Part Name GE Part # USAI Part # Qty
Coil / Cable Assembly, PA Volume Neck Coil, 1.5T 2254930-2 100125 1
Bridge, PA Volume Neck Coil, 1.5T 2254930-3 110042 1
Pad, PA Volume Neck Coil, 1.5T E8800PF 150001 1
Wedge Pads (Set of 2), PA Volume Neck Coil, 1.5T E8800PH 150030 1
Phantom Positioner, PA Volume Neck Coil, 1.5T E8800PG 150033 1
Phantom, PA Volume Neck Coil, 1.5T 46-265826G6 1
Adapter Block, PA Volume Neck Coil, 1.5T 2254931-5 150031 1
Operator's Guide, PA Volume Neck Coil, 1.5T 2254931-6 770013 1
Service Manual, PA Volume Neck Coil, 1.5T 2254930-7 780007 1
Table 3: Phased Array Volume Neck Coil (GE Part Number E8800PJ)
shipping list for Signa Horizon 1.5T system.
Part Name GE Part # USAI Part # Qty
Coil / Cable Assembly, PA Volume Neck Coil, 1.0T 2254931-2 100127 1
Bridge, PA Volume Neck Coil, 1.0T 2254931-3 110043 1
Pad, PA Volume Neck Coil, 1.0T E8800PF 150001 1
Wedge Pads (Set of 2), PA Volume Neck Coil, 1.0T E8800PH 150030 1
Phantom Positioner, PA Volume Neck Coil, 1.0T E8800PG 150033 1
Phantom, PA Volume Neck Coil, 1.0T 46-265826G6 1
Adapter Block, PA Volume Neck Coil, 1.0T 2254931-5 150037 1
Operator's Guide, PA Volume Neck Coil, 1.0T 2254931-6 770014 1
Service Manual, PA Volume Neck Coil, 1.0T 2254930-7 780007 1
Table 4: Phased Array Volume Neck Coil (GE Part Number
E8800PK) shipping list for Signa Horizon 1.0T system.
2. Installing the Coil At the console, install a new soft key. This soft key will be used by the
operator to select NECKPA. Refer to the system manuals for information
on installing soft keys (use the phased array and coil default values shown
below).
Coil Number of Start Stop Recon Port Enable Error Enable
Name Receivers Receiver Receiver Enable Mask Mask Mask
NECKPA 2 0 1 0 3 3
Table 5: Phased array values.
Rev. A (9/99) Page 5 of 12
USA Instruments, Inc. Phased Array Volume Neck Coil Service Manual
SETUP AND CALIBRATION (continued)
Coil Extremity Recon Scale Xmit Coil Multi
Coil Name Cable Loss Coil Loss
Type Coil Factor Type Coil
NECKPA 3 no 1.05 0.313 1.00 quad yes
Table 6: Coil values for Signa Horizon 1.5T.
Coil Extremity Recon Scale Xmit Coil Multi
Coil Name Cable Loss Coil Loss
Type Coil Factor Type Coil
NECKPA 3 no 1.24 0.103 1.00 quad yes
Table 7: Coil values for Signa Horizon 1.0T.
The coil is ready for clinical use after proper installation of the soft key.
Refer to the Operators Guide for instructions on use of the coil.
3. Quality Assurance Tuning -- The Phased Array Volume Neck Coil does not require matching or
tuning on a per patient basis. The coil is initially tuned to the system frequency
by USA Instruments service engineers and requires no additional tuning.
QA Check -- It is recommended that the clinical user conduct a QA check
on the Phased Array Volume Neck Coil on a weekly basis. The QA check
consists of a QA scan, a calculation of the signal-to-noise ratio (SNR) and a
visual inspection of the coil phantom image.
QA Setup -- Select [New Study], [New Exam] or [New Pt] to set a new
landmark. Remove any other surface coil (if present) from the cradle. Place
the Phased Array Volume Neck Coil near the top of the cradle. Place the
Head TLT Sphere with Nickel Chloride Phantom (GE Part # 46-265826G6)
on the positioner in the coil (see Figure 3). Connect the Phased Array
Volume Neck Coil connector to the phased array port. Align the laser with
the marks on the coil bridge and with the cross marks on the coil sides.
Position the coil at isocenter. The critical parameters for the QA scan protocol
are listed on the next page. Select [Scan]. Scan the phantom. Observe the
resulting image of the phantom which should be similar to Figure 4. Check
to see that there are no artifacts in the image. This image will be used for
determination of the coils SNR.
Bridge
Phantom
Positioner
Base
Figure 3: Positioning the phantom.
Rev. A (9/99) Page 6 of 12
USA Instruments, Inc. Phased Array Volume Neck Coil Service Manual
SETUP AND CALIBRATION (continued)
Pat ient /Exam I nformat ion
ID QA
Name C-Spine
Patient Weight 111 lbs / 50 Kgs
Pat ient Pos it ion
Patient Entry Head First
Patient Position Supine
Axial/Sag Landmark
Coil Type USVOLNECK
Scan Plane Sagittal
I maging Paramet ers
Image Mode 2D
Pulse Sequence Fast Spin Echo
Imaging Options Fast
Sc an Timing
Number of Echoes 1
Echo Time (TE) 28 msec
Rep Time (TR) 300 msec
Scan Time 22 sec
Echo Train Length (ETL) 4
Sc anning Range
Field of View (FOV) 26 cm
Scan Thickness 3 mm
Interscan Spacing 0 mm
Start Loc 0
End Loc 0
Number of Scan Locations 1
FOV Center 0 LR, 0 AP
Ac quis it ion Time
Acq Matrix (Frequency) 256
Acq Matrix (Phase) 256
Frequency Direction A/P
NEX 1
Phase FOV 1.00
Autoshim On
Auto CF Peak
Table 8: QA scan parameters.
Rev. A (9/99) Page 7 of 12
USA Instruments, Inc. Phased Array Volume Neck Coil Service Manual
SETUP AND CALIBRATION (continued)
SNR Measurement -- Select the phantom image. Select the circular cursor.
Size the cursor so that it represents a circular region of interest (ROI) of
600mm2 (approximate). Position the center of this circle at approximately
60mm from the edge of the phantom (see Figure 4). Record the phantom
mean pixel value. Reposition or recreate the same circular ROI in the
background region (see Figure 4). Check to see that the background is free
of any artifact. Record the background mean pixel value. Calculate the
images signal-to-noise ratio (SNR = phantom mean pixel divided by
background mean pixel). SNR should be greater than ______ (for 1.5T) or
______ (for 1.0T).
Signa 1.5T
Ex: 50486
Background
Phantom
<
Scan
<
< 60mm
Coil
FSE
TR:300
TE:28
EC:1/1 16kHz
USVOLNECK
FOV:26x26
3.0thk/0.0sp/C 1: m 2111.47, sd 88.28, a 729.12mm2
Figure 4: SNR measurement.
Visual Check of the Phantom Images -- The user should study the sagittal
image of the phantom that was obtained for the SNR analysis to spot any
large dark signal voids or significant signal non-uniformity. Signal voids and
signal non-uniformity may indicate potential problems with an individual
coil or coils. Contact your service engineer for troubleshooting.
Rev. A (9/99) Page 8 of 12
USA Instruments, Inc. Phased Array Volume Neck Coil Service Manual
REPLACEMENT AND MAINTENANCE
1. Checking the Protection Pin Select the DIODE TEST function on the DMM. Connect the negative lead
Diodes and Output Cable to the connector pin on Row A. Connect the positive lead to the pin on Row
with DMM B. Refer to the table and illustration above. A reading of 0.50 volts to 0.55
volts should be observed. If a reading below 0.40 volts is observed, either
the output cable is shorted or one of the pin diodes on the feeding board is
defective. If a reading above 0.65 is observed, either the output cable or the
jumper is open.
15 11 6 1
B
A
Figure 5: Pin locations for Bendix 30
pin phased array connector.
Pos it ive Lead Negat ive Lead
Coil Number Vol t age Reading
Connec t ion Connec t ion
1 3B 3A 0.51 (+/-.10)
2 5B 5A 0.51 (+/-.10)
Table 9: Pin diodes and output cable with DMM
for Signa Horizon 1.5T.
Pos it ive Lead Negat ive Lead
Coil Number Vol t age Reading
Connec t ion Connec t ion
1 3B, 3A 2B, 2A 0.51 (+/-.10)
2 5B, 5A 4B, 4A 0.51 (+/-.10)
Table 10: Pin diodes and output cable with DMM
for Signa Horizon 1.0T.
Rev. A (9/99) Page 9 of 12
USA Instruments, Inc. Phased Array Volume Neck Coil Service Manual
REPLACEMENT AND MAINTENANCE (continued)
2. Field Replacement Unit List
Part Name GE Part # USAI Part # Qty
Coil, PA Volume Neck Coil, 1.5T 2254930-2 100125 1
Bridge, PA Volume Neck Coil, 1.5T 2254930-3 110042 1
Cable Assembly, PA Volume Neck Coil, 1.5T 2254930-4 110037 1
Pad, PA Volume Neck Coil, 1.5T E8800PF 150001 1
Wedge Pads (Set of 2), PA Volume Neck Coil, 1.5T E8800PH 150030 1
Phantom Positioner, PA Volume Neck Coil, 1.5T E8800PG 150033 1
Phantom, PA Volume Neck Coil, 1.5T 46-265826G6 1
Adapter Block, PA Volume Neck Coil, 1.5T 2254930-5 150031 1
Operator's Guide, PA Volume Neck Coil, 1.5T 2254930-6 770013 1
Service Manual, PA Volume Neck Coil, 1.5T 2254930-7 780007 1
Table 11: Phased Array Volume Neck Coil field
replacement unit list for Signa Horizon 1.5T.
Part Name GE Part # USAI Part # Qty
Coil, PA Volume Neck Coil, 1.0T 2254931-2 100127 1
Bridge, PA Volume Neck Coil, 1.0T 2254931-3 110043 1
Cable Assembly, PA Volume Neck Coil, 1.0T 2254931-4 110038 1
Pad, PA Volume Neck Coil, 1.0T E8800PF 150001 1
Wedge Pads (Set of 2), PA Volume Neck Coil, 1.0T E8800PH 150030 1
Phantom Positioner, PA Volume Neck Coil, 1.0T E8800PG 150033 1
Phantom, PA Volume Neck Coil, 1.0T 46-265826G6 1
Adapter Block, PA Volume Neck Coil, 1.0T 2254931-5 150037 1
Operator's Guide, PA Volume Neck Coil, 1.0T 2254931-6 770014 1
Service Manual, PA Volume Neck Coil, 1.0T 2254930-7 780007 1
Table 12: Phased Array Volume Neck Coil field
replacement unit list for Signa Horizon 1.0T.
Rev. A (9/99) Page 10 of 12
USA Instruments, Inc. Phased Array Volume Neck Coil Service Manual
REPLACEMENT AND MAINTENANCE (continued)
3. Replacing the External
Cable Coil Former
PG11 Hex Nut
SMA Connector
Strain Relief
Figure 6: Cable assembly.
Step 1 -- Unscrew the bottom cover of the coil.
Step 2 -- Detach the two SMA connectors from the baluns.
Step 3 -- Loosen and detach the PG11 hex nut and pull the cable assembly
out from the coil.
Step 4 -- Install the new cable assembly and tighten the hex nut.
Step 5 -- Connect the two SMA connectors on the cable to the baluns.
Step 6 -- Reassemble the bottom of the coil with screws.
4. Replacing the Anterior The anterior bridge assembly is a field replaceable unit and can be simply
Bridge Assembly interchanged with the original assembly. However, to ensure correct fit and
ease of engagement of the anterior assembly to the coil, it is strongly
recommended that the service engineer follow the following procedure (see
Figure 7 for guidance).
Step 1 -- Unscrew the top cover from the bridge assembly and loosen (using
an 11/32 inch nut driver) both nuts that secure the connector pins.
Step 2 -- Place the bottom portion of the bridge assembly on the C-Spine
section of the Volume Neck Coil. Then tighten both nuts.
Step 3 -- Remove the bottom portion of the bridge assembly from the Volume
Neck Coil. Then tighten down the connector pin and nut assembly by using
the 11/32 inch driver to torque the nut and a 1/4 inch driver to keep the
connector pin from rotating.
Rev. A (9/99) Page 11 of 12
USA Instruments, Inc. Phased Array Volume Neck Coil Service Manual
REPLACEMENT AND MAINTENANCE (continued)
Step 4 -- Place the bottom portion of the bridge assembly back on the
Volume Neck Coil to check that the alignment of the connector pins is
correct. If the bridge does not install smoothly on the Volume Neck Coil,
loosen the nuts and pin assemblies. Repeat Steps 2 and 3 to realign the
pins. If the assembly of the bridge and coil continues to be a problem after
repeating the procedures, return the coil for evaluation.
Step 5 -- If the bridge engages correctly, then reassemble the top and bottom
portions of the bridge.
Assembly Instruction for
Connector Pins and Nuts
Step 1:
Remove top cover of
the bridge.
Tighten all four nuts Tighten all four nuts
using 11/32 nut driver. using 11/32 nut driver.
Step 2:
Tighten all four nuts
with the bottom portion
of the bridge in place.
Step 3:
Remove bottom portion
of the bridge and tighten
the nut and the connector Tighten all four nuts
pin using nut drivers using 11/32 nut driver.
simultaneously.
Figure 7: Replacing the anterior bridge assembly.
5. Coil Care Before Cleaning -- Detach the coil connector from the scanner before
attempting to clean. Prevent touching the connectors with bare fingers.
Prevent pressing a sharp object against the surface of the connector.
Caution! Do not pour or spray cleaning liquid directly onto the coil or cable.
Do not allow any moisture to come in contact with the connector or cable.
Do not immerse the coil in any cleaning liquid.
Cleaning -- The following solutions are recommended for the coil and pad
surfaces: (1) warm water, (2) one ounce commercial dishwashing liquid
mixed with one gallon water or (3) a ten percent bleach solution (some
discoloration may occur). Apply cleaning solution to a soft cotton cloth
and proceed to clean. It is recommended that the user place a cotton sheet
over the coil before positioning the patient to prevent soiling of the coil. In
the event the coil is soiled, clean the coil as described above.
Carrying the Coil -- The coil should be supported from underneath using
both hands. The coil should never be lifted by the anterior section.
Rev. A (9/99) Page 12 of 12
