Radcal Accu Series User manual

The Accu-Series -
Accu-Pro™
Accu-Dose
Accu-kV ®
Radiation Measurement
Systems
User Guide

Radcal Corporation
426 West Duarte Road
Monrovia, CA 91016-4591 USA
USA [phone]
Fax USA [phone]
email [email protected]
www.radcal.com
Radcal Part # MCD/9096
4091099 Rev:K4
Firmware V6.08 (Accu-Pro)
Firmware V7.03/V7.23 (Accu-Dose)
Firmware V5.22 (Accu-kV)
Printed: Feb 2013

INTRODUCTION ................................................................. 4
GETTING STARTED ............................................................. 6
MAKING ION CHAMBER MEASUREMENTS ..................................... 11
REFERENCE .................................................................... 12
Display ................................................................... 12
Sounds ................................................................... 13
Sensors .................................................................. 14
Main–Menu Functions .................................................... 17
Setup–Menu Functions ................................................... 19
Batteries ................................................................. 21
PERFORMANCE ................................................................ 23
Environmental conditions ................................................ 23
kV Sensors ............................................................... 23
Diode Sensors ........................................................... 25
Ion chambers ............................................................ 25
Ion Chamber Dose Timing Specifications ................................. 25
Waveform Output ........................................................ 36
Part numbers ............................................................ 36
OPERATOR MESSAGES ........................................................ 37
Self-test .................................................................. 37
Accu-kV .................................................................. 37
Ion chambers and dose diodes ........................................... 38
ACCESSORIES ................................................................. 41
XLPRO Excel add-in ...................................................... 41
90M9 mAs Sensor ........................................................ 42
90M10 mAs Sensor ....................................................... 43
10A96 Ion chamber Adapter .............................................. 44
Chamber Positioner ...................................................... 45
Accu-Pro™ System Carrying Cases ...................................... 46
APPENDIX - Mammography kVp measurements on Hologic Selenia ..................... 47
3

INTRODUCTION
The Accu-series instruments include the Accu-Pro™ for Dose and kV, the Accu-Dose for Dose only and
Accu-kV for kV only measurements. This manual is applicable to all instruments in the Accu-series.
The Accu-Pro™ system measures the characteristics of a diagnostic x-ray machine. Measurements are
processed and displayed by a microprocessor-based control unit. Sensors connect to the control unit via
a 4m cable that carries only digital signals and operating voltages to eliminate cable noise. Dose is
measured with ion chambers or solid-state detectors. Radcal Accu-kV sensors determine kV, filtration
and half-value measurements (diagnostic sensor) using differential absorption and an array of solid state
detectors. The mammographic (22-40kV) sensor Mo/Mo outputs can be corrected to W/Rh and W/Ag
anode-filter combinations (Hologic Selenia x-ray machine only).
A 13 kHz sample rate for kV measurements is used with FFT-based ripple measurements for accurate
kVp measurements on high-frequency generators.
Automatic compensation of kV measurements for filtration is available for diagnostic x-ray
measurements. This also provides estimates for filtration and half-value layer.
Stand-alone exposure measurements can be made using the Ion chamber digitizer and an ion chamber
or the dose diode digitizer and the DDX6-W or DDX6-M sensors. Using these sensors in conjunction with
the kV sensors provides dose and dose rate measurements synchronized to an x-ray pulse.
Using 40X11-W and DDX10-W or 40X10-M and DDX10-M sensors allows simultaneous dose and kV
waveform measurements
mA, mAs and mA waveform may be measured in conjunction with kV measurements using invasive or
non-invasive mA sensors.
The Accu-Pro™ operates from rechargeable NiMH or alkaline C cells.
The figure on page 46 shows the Accu-Pro™ system in its carry case.
A USB interface allows a PC to control and process measurements performed by the Accu-Pro™ system
. XLPRO, an Excel add-in, uses this capability to produce reports, graphs and to automate
measurements.
The figure on page 40 shows the pushbutton controls and the 2-line display. The connectors for the mA
sensor, USB and waveform are also visible. The battery charger interface is at the rear of the control unit.
The in-beam sensor connector is on the opposite side.
The controls include UP-arrow, DN-arrow and select pushbuttons that are used to navigate the menu
and to activate measurements. A test pushbutton provides a simulated x-ray signal so you can observe
how the measurements work. The power pushbutton provides for orderly shutdown and startup.
Measurement results are presented on the display and are available in digital form on using the USB
connection. The BNC provides calibrated real-time kV, dose or mA waveforms.
4

Accu-Pro™ Diagnostic Ion Chamber and kV Sensor Components
A. Accu-Pro™ (9096) Control Unit
B. 40x12-W Diagnostic Range kV Sensor
C. 10X6-6 Ion Chamber Sensor
D. Positioner
E. 9660 Ion Chamber Digitizer
F. 90C6-4 Sensor Cable
5

Sensor cable connection
kV sensor connection
Ion chamber connection
GETTING STARTED
This describes initial assembly and operation of an Accu-Pro™ system comprising a control unit, sensor
cable, diagnostic kV sensor and a 6cc ion chamber with an ion-chamber digitizer.
IMPORTANT: Stabilization is required before making any ion chamber measurements.
Stabilization is best done by putting the unit in Dose Rate mode/High Sensitivity and waiting for 3
minutes. See page 11 for details.
Connect the sensor cable to the control unit:
Insert the rectangular connector on the sensor cable into
the socket on the right side of the instrument with the
Radcal logo facing you. It will click into place. To remove
it, pinch the levers on the side of the connector and pull
back.
Connect the kV sensor to the sensor cable:
Hold the round connector by the rubber strain relief
and engage the kV sensor by rotating the connector
until it aligns with the mating socket on the sensor and
they move to engage, then press the connector. It
should click into place. To disconnect, pull straight
back on the ring, not on the strain relief, and the
connector will unlatch. Never attempt to unscrew the
connector.
Connect the Ion chamber
Connect the ion chamber to the larger
circular connector on the Ion chamber
digitizer. Align the red dots and push the
connector until the mating surfaces
contact one another. Connect the sensor
cable to the smaller connector in the same
fashion.
6

Connect the battery charger:
Connect the charger to the control unit
and plug it into an ac outlet. The charge
indicator should turn on orange indicating
the battery is being charged. The
instrument can operate while the battery
is being charged.
7

Turn on the Accu-Pro™:
Press the green power button. A set of vertical rectangles marches across the display to assure it is
operating, the calibration date is displayed, and self-test is performed. During self-test the control unit
reads the type and calibration factors of each sensor, measures the ion chamber temperature and the
ambient pressure. When self-test completes, the display will show the chamber information:
6cc Corr 1.03
HV Stabilize 13s
while the ion chamber and bias supply stabilizes. When the stabilization times out, pressure and
temperature display:
Press 99.2 kPa
Temp 20.1 deg C
The Corr value shown is the temperature and pressure correction that will be applied to the ion chamber
readings.
The top line of the display will then show:
Change or SELECT
and the second line will show setup or whatever measurement mode was active the last time power off
occurred.
If self-test is unsuccessful, a failure message is displayed. Pressing UP or DN allows operation to
proceed, however you must resolve the problem before accurate measurements can be performed. See
the discussion of error messages on page 37
Setup Defaults
The Accu-Pro™ has a number of options that are controlled from the Setup menu. The following
procedure resets the setup functions to factory defaults. Use UP to get
Change or SELECT
Setup
and press select to enter Setup . Press DN twice. The display should show:
SELECT restores
setup defaults
Then press select:
Accept changes ?
> OK
appears. Use DN until:
Press SELECT to
exit Setup:
appears. Press select.
Accept changes?
> OK
appears again. Press select to return to the main menu with all settings at factory defaults.
8

Functional test
Now that the Accu-Pro™ is operating, you can use the test button to become familiar with the operation
of the unit. The UP and DN arrows move through the main menu. The top line of the display continues to
show
Change or SELECT
while the second line shows the function to be performed.
Dose Rate test
Use UP or DN to reach the Dose Rate function, and press select.
The display will briefly show
6cc Corr 1.02
measuring zero
after which it will become
[Dose Rate
0.0 mR/min
The up arrow indicates low-sensitivity mode.
Press and hold test
The display becomes:
[Dose Rate
999.5 mR/min
The dose rate value depends on the ion-chamber calibration factor. It lies between 940 and 1060
mR/min.
KV Pulse test - Diagnostic sensor 40-160kV
Press UP or DN until the display shows:
Change or SELECT
kV Pulse
Press select.
After a few seconds, the display changes to:
kV Pulse
W
while the kV sensor zero is being determined. After another few seconds, the annunciator beeps, the W
disappears and the system is ready to perform a measurement:
kV Pulse
A
The A indicates automatic filtration correction is active.
Press test. The kV sensor responds as if it had been exposed to a 100kV, 100 ms x-ray signal. When the
kV sensor detects a signal, the display becomes:
kV Pulse
The arrow indicates a signal is being measured. The arrow is replaced by a Wwhen the pulse ends and
kV calculations are being performed. Finally, a beep sounds, the W disappears and the measurement
results are displayed:
98.4 kVp
A1.99mR l 100ms
The kVp reading results from the filtration correction for 10mm Al.
9

Pressing select displays filtration:
0.300 mm Cu HVL
A10.0mm AL 7.12
Pressing select again displays dose measurements:
1.993mR/pls
A1.196R/min C
The C indicates the radiation measurement comes from the dose sensor.
KV Pulse test - Mammographic sensor 22-40 kV
The factory default setting is for a Mo/Mo track filter combination. To change to another combination see
MODE SELECT in Setup (page 19). See Appendix (page 47) for calibration example.
Attach the mammography kV sensor to the control unit.
Use UP DN to come to
Change or SELECT
kV Pulse
Press SELECT and have the display show
kV pulse
Press test. The kV sensor responds as if it had been exposed to a 30kV, 100 ms x-ray signal. The
display shows for a Mo-Mo setting
30.0kVp
Dx.xxmR 100ms
The D stands for default filtration - 30μm Molybdenum for the Mammography sensor
For a Tungsten/Rhodium setting, you will see a T in the lower left of the display after you select kV pulse.
On pressing the test button, you then have the display show
31.6kVp
Txx.xxmR 100ms
A Tungsten/Silver setting is different from the Tungsten/Rhodium setting. There is a range of calculated
kVp's (25-33kV) that exceed a set error band and the instrument will show an error message as a result.
The test button shows what this looks like. You will get two successive screens. The first reads
Exposure error
Bad W/Ag kV
The next screen reads
kV-try again
SError cleared
The S stands for silver
Once the measurement has been completed, the display retains the values. A subsequent exposure does
not replace them until the measurement is complete The >and Wappear to the left of the exposure value
to indicate signal–present and kV– calculation respectively. When the Wdisappears, a beep sounds and
the new reading is displayed. An exposure made when either > nor Ware displayed will not be correctly
analyzed.
10

MAKING ION CHAMBER MEASUREMENTS
1. Allow the system to reach equilibrium by selecting dose rate mode and waiting at least three
minutes. Do not touch digitizer. One does not need to shut the system off when replacing
chambers, however, do not disconnect the chamber when actual measurements are being made.
Each time a new chamber is used, the system must re-stabilized
.
Note: For changing environments, allow 10 minutes per 10 C for the sensor/electronics to
equilibrate.
2. Ensure that the system is set to high sensitivity on
(Setup->Mode SELECT->High sensitivity->On). This ensures that the system performs a fine
zero (as opposed to a coarse zero) prior to every measurement.
3. Do not move or touch the digitizer or the ion chamber during the zero measurement interval. If
low-level measurements are being made and there is a significant delay between measurements
(> 2-3 minutes) it is prudent to force a full re-zero by exiting the mode and re-entering.
11

REFERENCE
Display
The 2-line 16-character LCD displays menu selections and measurement results.
Characters positioned at the left side of the display have special meaning:
>in Setup indicates a parameter choice. Press select to chose the item.
For dose measurements:
?indicates dose-sensor signal was outside calibrated range .
>indicates high-sensitivity mode measurement.
[indicates low -sensitivity mode measurement.
]indicates cumulative (zero-corrected) dose is negative.
For kV measurements:
Wmeans Wait. The kV system is unable to process another exposure while W is displayed.
Aindicates automatic filtration compensation is enabled.
Dindicates default filtration will be used: 2.5 mm Aluminum for the diagnostic sensor.
30μm Molybdenum for the Mammography sensor
Mindicates a user-selected filter (other than 2.5 mm Al).
Tindicates a Tungsten/Rhodium anode/filter
Sindicates a Tungsten/Silver anode/filter
In the lower right corner of the display:
Cindicates a dose sensor (ion chamber or diode)
Kindicates dose from the Accu-kV diode
The kV display may be configured in Setup. The following table shows the selections for each of the four
locations on the display. Default values are underlined.
Location Measurement
Upper Left kVp kV practical kV
reduced
kV avg
Upper
Right mAs width
pulses
width
ms
mA
Lower
Left conv dose width
pulses
width
ms
mA
Lower*
Right width ms kV diode
dose rate
rel
dose rate
pulses
* Readout not present if Lower Left is Conv Dose in kV
12

Fluoro Display Scrolling:
The kV displays provide filtration information by scrolling the display using select. A second press of
select in kV Pulse and Dental modes provides exposure information if a dose sensor or Accu-kV diode is
connected and displayed.
Sounds
A brief(5ms) 4 kHz tone is produced whenever a key-press is recognized. A longer (100 ms) tone occurs
when the kV measurement computation finished and a new reading is displayed. The longer sound also
occurs when an error occurs.
13

40X12-W Accu-kV
The sensor for Diagnostic range (40 kV to 160 kV) measurements
Besides kVp, also measures, displays, and compensates for beam hardness(add ± 1 % when
on). Inherently correctly reads AMX4+ and AMX 700 portables. Flash HVL: ± 0.3 mm Al and ±
10 % of reading, 1-23 mm total equivalent thickness Al, 40-160 kVp.
40X9-Mo Accu-kV
The sensor for Mammographic range measurements
This versatile sensor is designed for 0.5 kV accuracy for Mo-Mo mammographic beams. It may
also be used at < ± 1 kV accuracy for Tungsten-Silver / Rhodium tubes on Hologic Selenia
mammography machines.
Recommended for starter kit configuration.
FFT kV SENSORS with FLASH HVL (diagnostic range)
The Diagnostic range sensor accuracyis ± 1kV or ±1 %whichever is largest. Themammosensor has an Mo-Mo
accuracy of ± 0.5 kV and < ±1 kVfor other track-filters.
Sensors
The Accu-Pro™ control unit can connect to various sensors to provide dose and x-ray beam information.
The three main classes of sensors are the Accu-kV sensors that determine x-ray beam characteristics,
the ion chambers that measure radiation dose and the diode-based radiation sensors. Also available are
mA sensors used to determine x-ray anode current.
KV sensors
The Accu-kV sensors use differential absorbers and photodiodes to determine kV. You can select the
filtration to be used for kV calculations in Setup. Automatic filtration correction is available for the
diagnostic sensors. Both mammographic and diagnostic sensors are available that can accept a dose
diode input for observing radiation waveforms and to provide dose measurements synchronized to with
the kV pulse.
Diagnostic sensors are black; mammographic ones are purple.
40X9-M - Basic mammographic Accu-kV sensor.
40X10-M - Same as 40X9-M with provision for DDX-10M diode sensor to observe radiation
waveform using oscilloscope or XLPRO. (Discontinued - see below)
40X9-W - Basic diagnostic Accu-kV sensor. (Discontinued - see below)
40X10-W - Same as 40X9-W with provision for DDX-10W diode sensor to observe radiation
waveform using an oscilloscope or XLPRO (Discontinued - see below)
40X11-W - Same as 40X9-W with provision for DDX-10W and automatic filtration compensation.
(Discontinued - see below)
40X12-W - Same as 40X9-W with automatic filtration compensation.
14

ION CHAMBER DOSE SENSORS
The Ion Chamber Dose Sensors feature:
Calibration Accuracy ± 4%, Energy Dependence ± 5%. Plug-and-play.
10X6-6
The General Purpose, in Beam Chamber
A well documented wide dynamic range chamber with many dose
and rate applications.
10X6-6M
The Dedicated Mammography Chamber
A world standard for mammography.
10X6-60
The 'Service' Chamber
This thin profile makes it ideal for low input dose at an image
receptor and many other uses.
10X6-3CT
The Chamber for Computed Tomography Dose Index (CTDI)
Another industry standard.
10X6-180
The Leakage and Low Level Measurements Chamber
For leakage measurements. Cross-section of 100cm2. Also for very
low dose to image receptor.
10X6-1800
The Radiation Protection Chamber
For very low-level radiation measurements such as sheilding,
leakage, and environmental. Superior to typical survey meters for
accuracy.
Recommended for starter kit configuration.
Ion Chambers
Radcal ion chambers are recognized for reliable measurements They exhibit excellent energy response.
Their omnidirectional response makes them suitable for leakage and scatter measurements as well an
CT measurements. They are available in specialized configurations for particular systems. Ion chambers
require care in handling, require a bias voltage which must stabilize after bias is applied, and are much
larger than diode sensors.
15

DIODE DOSE SENSORS
The Diode Dose Sensors feature:
Calibration Accuracy ± 4%, Energy Dependence and Filtration dependence: see below.
DDX6-W
The Diode Dose Sensor for Diagnostic range measurements
Energy dependence ± 5 %, 40-150 kV at 2.5 mm Al. Filtration
dependence + 5 % to -10 % for 2.5 to 23 mm Al.
DDX6-M
The Diode Dose Sensor for Mammographic range measurements
Energy dependence ± 5 %, 20-40 kV, 25-35 µm Mo. ± 5 % 25-35 kV 30
µm Mo + 2 mm Al. ± 10% 22-40 kV, 30 µm Mo + 2 mm AL.
Recommended for starter kit configuration.
Diode dose sensors
Diode sensors are compact, rugged, insensitive to handling, “instant-on” and do not require temperature
and pressure correction’ They are somewhat directional which reduces the effect of scatter. Their
energy response is not as uniform as the 10X6 ion chambers. Their directional response makes them
unsuitable for CT, scatter and leakage measurements. Temperature-dependent leakage current makes
them unsuitable for long-term dose measurements.
Accu-kV diode sensors (DDX10) are available that work in conjunction with an Accu-kV sensor. They
allow viewing radiation waveforms captured simultaneously with kV waveforms. They cannot make stand-
alone radiation measurements. (Discontinued
DDX6 diode sensors connect to the DD60 diode digitizer. They are standalone dose sensors providing a
full set of radiation measurements.
Relative dose:
The relative dose rate output is based on a single channel from the kV sensor. It is uncalibrated and
uncompensated, however it can serve as a measure of relative output for consistency tests and the
analog or USB waveform can assist in troubleshooting.
16

Main–Menu Functions
Italics indicate default functions. Using Setup you can add or remove functions to customize the main
menu. A flow chart representation of the main menu is shown on the enclosed diagram.
Setup
Provides access to configuration settings. See Setup–Menu Functions on page 19.
Dose Rate
Measures and displays dose rate. Performs an auto-zero and measures environmental conditions when
the mode is first selected. Applies that value to each reading. Measurement interval depends on dose
rate and varies between 0.3 and 5 seconds. An arrow in the upper left corner is on when a measurement
is in process. It points upward when low sensitivity mode is selected, and to the right the for high
sensitivity.
Max Dose Rate
Measures Dose rate. Displays the result only if the measured rate is greater than that displayed. select
resets the stored value.
Dose Accum/Hold
Measures total dose. Performs an auto-zero and measures environmental conditions when mode is first
selected and applies those values to the measurements. A down-pointing arrow in the upper left of the
display appears when accumulated zero-corrected dose is negative; up- and right-pointing arrows
indicate measurements in normal and high-sensitivity modes respectively. Updates the display once per
second.
Pressing select resets the accumulation but not the zero.
Auto Dose
Automatically measures the dose and duration of a single exposure. Displays the result until another
exposure occurs. Starts when the dose rate exceeds 0.01% FS; stops accumulating dose 200 ms after
the rate falls below 0.006% FS. Duration is measured between the trigger point and 50% of the peak rate.
The ending delay allows collection of all the charge in the exposure.
Last Dose
Like Dose Accum/Hold except select doesn’t reset the dose accumulator. The accumulator is updated
every 500 ms.
Pulsed Cine
Accumulates dose and displays it in units of dose per pulse or dose rate. Use Setup to define 6
measurement conditions, each of which specifies pulse rate (pulses/s), delay(pulses) , acquisition(pulses)
and threshold(varies with chamber). Available pulse rates include automatic (indicated as 0 pulses /s)
that works up to approximately 16 pulses/s and selected values between 0.25 and 90 pulses/s. The x-ray
machine must be operating during the entire time of the measurement.
kV Pulse
Measures and displays kVp and duration. If a dose sensor is connected measures and displays pulse
dose and dose rate. If the mA sensor is connected integrates mA to obtain mAs. Displays mA or mAs.
kVp measurements are calculated using a 100ms interval near the end of the pulse. Analyzes kV
waveforms up to 5 sec. Use select to access filtration and additional dose measurements. See page 12
for a description of the display options. See Display discussion on page 12 for the meaning of special
characters A, D and M (in filtration) and C and K (in dose).
17

kV Dental
Operates like kV Pulse. Disregards low-intensity preheat pulses if this feature is enabled in Setup.
Duration can display in pulses for 50- and 60-Hz half-wave machines.
kV Fluoro
Operates like kV Pulse. Measures kV for 1 second, computes and displays the result and then repeats.
Displayed values change slightly to adapt to a continuous waveform. Width measurements are omitted;
dose and mAs become dose rate and average mA respectively.
Power off
Turns the unit off. Saves the operating mode and displays
Power off
for several seconds and then removes power.
Occurs automatically after 30 minutes of inactivity or when power is pressed during operation.
18

Setup–Menu Functions
Pressing select at the main menu display
Change or SELECT
setup
enters Setup. The following information and options are provided in this mode::
!Serial No. and firmware Version
This manual applies to version 6.
!Pressure and temperature
Values used for ion-chamber compensation. Prefixed with Std if measured not selected.
!SELECT restores setup defaults.
Restores all items in Setup to default values. Default values are shown as Default in the following
descriptions.
See detailed instructions on page 8
!Mode SELECT
Parameter Choices Accu-Pro Accu-Dose Accu-kV
Pressure Measured/Std 101.3 kPa X X
Temperature Measured/Std 22 deg C X X
Len/area suffix On(*cm or *cm2)/Off XX
High sensitivity1On/Off XX
Radiation units Roentgens/Grays/Coulombs X X
Auto shutdown On(30 min)/Off X X X
Time units Seconds/Minutes/Hours X X X
Mammo anode/filter Mo/Mo, W/Ag, W/Rh X X
DAC output kV/mA/Rel. intensity/dose rate X X
1The Accu-Pro measures the background zero when you select a dose mode. If high sensitivity is set to
off, the system will make a quick coarse zero measurement. Some fluctuations will be observed in dose
rate mode and dose accumulate may exhibit drifting. If high sensitivity is set to on, the system will make
a fine zero measurement which takes 3 to 5 seconds. The dose rate will fluctuate much less and the
dose accumulate drift will be greatly reduced. It is recommended that high sensitivity mode is enabled for
most dose measurements.
!Function SELECT
Add/Remove functions from the main menu. See Page 17 for a list of functions
!kV disp(lay) SELECT
See table on page 12
!Intrinsic filt(ration) SELECT
Selects the filtration used to compute kV in the diagnostic range. Auto enables automatic calculation
based on beam hardness.
Auto, Cu (32 steps from 0 to 0.695 mm), Al (32 steps from 0 to 23 mm).
19

!Dent(al) thr(eshold) SELECT
Raised threshold for kV-Dental. Values are multipliers of the kV pulse threshold. 1, 10, 25, 50,
100, 250, 600, and 1500.
!Pulsed Rad Mod Index no. SELECT
Set up presets 0 thru 5 for Pulsed/Cine mode. For each, select four parameters:
Pulse Frequency
00.25.512345
66.2577.5891012.5
15 25 30 40 50 60 75 90
Trig threshold.
Number is relative dose rate. () is dose rate in nR/sec for 10X6-6
3 (55) 5(92) 10 (184) 18 (330) 30 (550)
55 (1000) 100 (1840) 182 (3300) 300 (5500) 500 (9200)
Acquire Delay
Number of frames: 1 - 256
converted to time based on selected pulse frequency
Acquire Interval
Number of frames: 1 - 256
converted to time based on selected pulse frequency
!Press SELECT to exit Setup
If any changes have been made, you then will see
Accept Changes?
> OK
select accepts the changes and returns to main menu.
UP or DN changes OK to Cancel and then select returns to the main menu discarding the changes.
20