RTI Cobia Reference Manual
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RTI Cobia Reference Manual

X-ray analyser/multimeter
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Cobia
Reference Manual - English - v2016.12A
RTI article number: 4760.001206

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Summary of Contents for RTI Cobia

  • Page 1 Cobia Reference Manual - English - v2016.12A RTI article number: 4760.001206...
  • Page 2 Welcome to the Cobia The Cobia is an X-ray Analyser/Multimeter for everybody working with Quality Assurance and Service of X-ray systems.
  • Page 3 Notice NOTICE RTI Group AB reserves all rights to make changes in the Cobia and the information in this document without prior notice. RTI Group AB assumes no responsibility for any errors or consequential damages that may result from the use or misinterpretation of any information contained in this document.
  • Page 4 - so that patients or other unqualified persons can change settings of operating parameters during and immediately before and after measurements. In Germany, the Cobia can also be used for dose measurements in the context of legal metrology (see the German user manual for more information).

  • Page 5: Table Of Contents

    2.1.1.3 Menu Overview ......................15 2.1.1.4 Keyboard Operation ......................16 2.1.1.5 Previous Measurements ......................16 Setting Up the Cobia for the First Time ........................17 Getting Started ........................17 2.3.1 Before Starting the Cobia for the First Time ........................17 2.3.2 Charging the Battery ........................18...
  • Page 6 Updating the System ........................61 2.8.3 Changing the Battery ........................62 Measurement Principles & Theory ..................... 64 Waveforms and Triggers ........................64 Measurement Principle for the Cobia ........................66 Linearity ........................67 Reproducibility ........................68 Problems and Solutions ..................... 70 Troubleshooting ........................70 Bluetooth ........................
  • Page 7 Chapter 1 Introduction...

  • Page 8: Introduction

    Descriptions on performing measurements with the system for different modalities. Troubleshooting tips and a glossary. Users who use the Cobia with only a PC and Ocean 2014 are recommended to read at least the following topics: Introduction Description of the Cobia Measurements with the Cobia System For the Cobia system, calibration data is stored inside the system.

  • Page 9: Computer Requirements

    In normal case when the Cobia runs standalone, no computer is required. But if the system of the Cobia shall be updated, a special part of the Cobia that is called Cobia Updater is used. This Cobia Updater requires a computer with the following requirements:...
  • Page 10 Chapter 2 Description of the Cobia...

  • Page 11: Description Of The Cobia

    2. Description of the Cobia Product Overview Description of the Cobia Product Overview The Cobia comes in a lot of different models, the external design is basically the same for all models (except for the External Probe port). TOP VIEW BOTTOM VIEW Cobia - Reference Manual Version 2016.12A...
  • Page 12 Used to move right or make a selection in the user interface. button See section Keyboard Operation Menu and On/ Used to start and power off the Cobia, and display the system Off button menu. See section Keyboard Operation Positioning...
  • Page 13 The USB port is used when using Cobia Updater to update the internal firmware. It can also be used when the Cobia Flex or Cobia Sense PC is used together with a PC running the QA software Ocean 2014. The system is then powered from the PC via the USB cable.

  • Page 14: User Interface

    (EXT), a corresponding indicator will appear in the leftmost side of the unit field (not shown). Note! The shown parameters may vary depending on the model of the Cobia. The Cobia - Reference Manual Version 2016.12A...
  • Page 15 (top of screen). System Info gives detailed information about the Cobia, needed during support. Power Off turns the Cobia off. When using an external detector or probe, there will be an extra menu Cobia - Reference Manual...

  • Page 16: Screen Indicators

    Top Of Screen Status Icons The external power supply is attached (fast charging). The Cobia is powered from a PC via USB (or non-compliant power supply). An external detector is attached to the EXT connector (some models). An external MAS cable is attached to the MAS connector (some models).
  • Page 17 Pulse Indicator To the left of the measurement figures on the single view screen, a symbol is lit when the Cobia detects at least 3 pulses in the waveform. Signal Source Indicator To the left of the unit field on the single view screen and to the left of each parameter data on the List view screen, a symbol will indicate the source of the parameter.
  • Page 18 2. Description of the Cobia Product Overview Unit Symbols Symbol for pulse, for instance dose per pulse. Symbol for pulse width (parameter P11). Symbol for duty cycle (parameter P12). In pulsed waveform the percentage the waveform is above 50 % per cycle.

  • Page 19: Menu Overview

    2. Description of the Cobia Product Overview 2.1.1.3 Menu Overview Cobia - Reference Manual Version 2016.12A...

  • Page 20: Keyboard Operation

    The function displays the 7 last sessions containing up to 99 measurements per session. Every time the Cobia is started a new session is created, unless the last session was empty (no empty sessions). The oldest session is then automatically deleted.

  • Page 21: Setting Up The Cobia For The First Time

    Then continue according to the following section. Getting Started 2.3.1 Before Starting the Cobia for the First Time Before using the Cobia for the first time, make sure the unit is charged. See Charging the Battery Cobia - Reference Manual...

  • Page 22: Charging The Battery

    2. Description of the Cobia Getting Started 2.3.2 Charging the Battery The battery can be charged in two ways: Via the USB cable connected to a PC. Via the USB cable connected to the included external charger. This is the fastest way of charging.

  • Page 23: Performing A Measurement

    8. When the measurement is over, the recorded values are by default cycled on the Cobia display. Press the right arrow button to go to the List view for an overview. 9. Compare the parameters displayed by the Cobia with the test settings for the X-ray unit.
  • Page 24 2. Description of the Cobia Performing a Measurement voltage is 70 kV or higher. In that case try to increase the distance to the tube or move it to position where the heel effect is less strong (typically towards the cathode side).

  • Page 25: Measuring With A General External Detector

    Performing a Measurement 2.4.2 Measuring with a General External Detector The description below describes how to use an external detector with the Cobia Sense or Flex. 1. Start the X-ray unit and start the Cobia. 2. Set up the external detector unit. For an external dose probe, place the detector at a clinically relevant distance (typically 50 - 100 cm from the source), as described by the manual of the detector.

  • Page 26: Measuring With A Light Probe

    2. Description of the Cobia Performing a Measurement 2.4.3 Measuring with a Light Probe In-depth instructions on how to use a Light Probe are found in the separate Light Probe manual. Attach the light probe monitor adapter (pictured below, left) for measuring the luminance of a monitor or light box, or the lux adapter (below right) for measuring illuminance (ambient light).

  • Page 27: Connecting The Mas Cable

    2. Remove the jumper from the mAs measuring socket of the generator. 3. Connect the Cobia MAS Cable to the mAs measuring socket using the safety cables Cobia - Reference Manual Version 2016.12A...

  • Page 28: Tube Current Safety Precautions

    Internal MAS is only intended for measuring the tube mA and mAs. Do NOT use the Cobia Internal MAS in contact with a patient. Do NOT use the Cobia Internal MAS on a circuit with a voltage higher than 90 V DC or 600 V AC.

  • Page 29: Measurement Settings

    X-ray equipment. It is not intended for use during diagnostic examinations of patients. RTI Group AB takes no responsibility for the misuse of the Cobia Internal MAS or use together with products that the Cobia Internal MAS is not intended for.
  • Page 30 2. Description of the Cobia Performing a Measurement Available settings are: 0,1 s, 3 s (default), 6 s, and 15 s. Trig level (time) Here you can set the level used for irradiation time measurements. "Trig level (time)" (TL) is normally set to 50 % of the peak...

  • Page 31: Error & Display Messages

    Too Low Signal The Cobia detects a signal but it is too low to present a reliable result. Increase the output, i.e. mA and/or decrease the distance from X-ray tube to detector.
  • Page 32 2. Description of the Cobia Performing a Measurement Reduce the mA and/or increase the distance from tube to detector. Too Low Voltage Measured tube voltage is lower than that of the selected kV- range. Change to a lower kV-range. Too High Voltage Measured tube voltage is higher than that of the selected kV- range.

  • Page 33: Hardware And Specifications

    If you get this warning triangle in front of the measurement value it means that the parameter is shown with reduced accuracy. For instance, if no kV/ TF could be found, the Cobia will display uncorrected dose and dose rate values, but mark them with this triangle. Then you can manually make the...

  • Page 34: Parameter Ids

    INT = the internal detector, MAS = the MAS connector, EXT = the external detector connector. The actual number of available parameters depends on the model of your Cobia, the art of the measurement, and what kind of external probes you have with your meter.

  • Page 35: Cobia Internal

    The Cobia internal detector is very sensitive and can measure peak tube voltage for as low outputs as 50 kV / 0.2 mA at 50 cm. The exact parameters depends on the Cobia, as shown in the table below.

  • Page 36: Power & Communication Specifications

    2. Description of the Cobia Hardware and Specifications using a combination of detector and filters in the Cobia. In situations when the total filtration cannot be automatically estimated, a "standard" HVL measurement may be required. All measured kVp and dose values measured with the Cobia are automatically compensated for the actual beam/radiation quality.

  • Page 37: Specifications, Cobia

    2. Description of the Cobia Hardware and Specifications 2.5.2.3 Specifications, Cobia The inaccuracy is here defined as the root of the square sum of systematic errors, which has not been eliminated, and random errors (dispersion around a mean value). The calculation of the inaccuracy is based on 15 different measurements and with a confidence level of 95 %.
  • Page 38 Waveform is calculated based on detector signals measured after different thickness of filtration. Dose rate waveform (P3) Signal measured from radiation detector (ionization chamber or solid- state detector). Note 1: The actual parameters available, depends on the Cobia Model, see section General Cobia - Reference Manual Version 2016.12A...
  • Page 39 2. Description of the Cobia Hardware and Specifications Measuring range and inaccuracy Radiography, Fluoroscopy, and Dental - Basic Parameters Parameter Range Inaccuracy Resolution kVp Smart/Flex (P1) 4 digits W / 3 mm Al 38 – 155 kV (10 or 100 V) ±2 %...
  • Page 40 Ocean PC software or by using the external communication protocol (see Cobia Communication Protocol ). For the Cobia this setting never affects the Irradiation time calculation as may happen in previous products. - Cobia Internal MAS, Invasive mAs cable Module type...

  • Page 41: Typical Response, Cobia

    2. Description of the Cobia Hardware and Specifications Note 1: When the Cobia internal detector or external dose detector is used simultaneously, the default mode of operation is to use that detector for time measurement. Note 2: The tube current is calculated as the tube charge divided by the time. See also...

  • Page 42: Manual Energy Correction, Cobia

    2.5.2.5 Manual Energy Correction, Cobia If the Cobia cannot measure tube voltage and total filtration, the dose values from the internal detector are left uncorrected. This is indicated by the yellow triangle . This can happen at very low dose rates.
  • Page 43 Hardware and Specifications Radiography, Fluoroscopy, and Dental (measured using RTI RQ Code R1, W/Al) This is only for energy compensation of the Cobia internal detector. For external detectors, like the RTI Dose Probe, see their respective manuals. Cobia - Reference Manual...

  • Page 44: Cobia External Probes

    2. Description of the Cobia Hardware and Specifications 2.5.3 Cobia External Probes The inaccuracy is here defined as the root of the square sum of systematic errors, which has not been eliminated, and random errors (dispersion around a mean value).
  • Page 45 Waveforms and Triggers Note 2: The standard calibration for the RTI External Dose Probe is W/23 mm Al. This calibration was chosen since the main use of the detector is to measure the dose to the image intensifier, after the phantom.
  • Page 46 7.000 s (3 kSa/s) For more details of available times, please see section Specifications, Cobia (internal detector). Typical Response The table below shows the typical response for the RTI External Dose Probe at standardized radiation qualities. Radiation quality Air kerma measurement Mean energy...
  • Page 47 ±1 pulse (P7) Note 1: When the Cobia internal detector is used simultaneously, the default mode of operation is to use the internal detector for time measurement. Note 2: The tube current is calculated as the tube charge divided by the time. See also...

  • Page 48: Cobia Communication Protocol

    The following describes the communication protocol for the Cobia with firmware version 5.9A. This communication protocol is available in all models of Cobia Flex and in the Cobia Sense PC model (not Cobia Sense). For an overview of the capabilities in the different models, see...

  • Page 49: Use Cases

    The following use cases have been considered for the design of the Cobia Communication Protocol: • The user must be able to connect to the Cobia Flex or Cobia Sense PC from a computer. • After a measurement, the user must be able to retrieve all the data values to be displayed.

  • Page 50: Command Structure

    0000. CCCC = CRC16 checksum in Hex format. If you do not use, please set it to XXXX. With this the Cobia can verify that nothing was corrupted during the transfer. ZZZ = command (case sensitive) – see list below optional parameters are separated by a semicolon.

  • Page 51: Parameter Ids

    You will find a full list of all parameters and their IDs in section Parameter IDs There you can also see the possible source of the parameter. The actual number of available parameters depends on the model of your Cobia (see section General ), the art of the measurement, and what kind of external probes you have with your meter.
  • Page 52 2. Description of the Cobia Cobia Communication Protocol Error/Warning/Message in data attribute (when fetching data) Attribute and Internal Description value Code Error="1" EC01 Error: General measurement error Error="2" EC02 Error: Negative signal error Error="3" EC03 Error: Too Low Signal Error="4"...

  • Page 53: List Of Commands

    The following table lists the available commands in firmware version 5.9A. The column Intr. lists the firmware version where this command was introduced. When the reply column says "OK" it means that the Cobia will respond with OK in the standard format. See example for Alive command below: Command from you: [CobiaC-2423XXXX-Alive]<CR><LF>...
  • Page 54 2. Description of the Cobia Cobia Communication Protocol Command Intr. Reply Function/Use connected: 0 = none, 1 = external only, 2 = internal MAS only, 3 = ext + iMAS. 5.1A DetCal;?/ ? gives selected detector and calibration (+calibration date Select detector / list/set;X;Y...
  • Page 55 2. Description of the Cobia Cobia Communication Protocol Command Intr. Reply Function/Use - "TrigDisabled" - When meas. turned off (eg menu.) - "TrigEnabled" - When meas. activated 5.1A SysMsg;?/ <CobiaR CobiaC=”SysMsg”>STATUS </CobiaR> Activate/deactivate or on/off where STATUS is ”on” or ”off”...
  • Page 56 2. Description of the Cobia Cobia Communication Protocol Command Intr. Reply Function/Use and remote control. 5.3A WFInfo <CobiaR CobiaC="WFInfo" ID="2423" CRC=""> Lists the parameters that <P3 Src="EXT" Unit="Gy/s">6.922E-02</P3> has a waveform, e.g. P1, <Samples>465</Samples> P3, (P4), P3/EXT, P18, P19, <SampleRate>3000</SampleRate>...

  • Page 57: Cobia Start-Up

    2. Description of the Cobia Cobia Communication Protocol Command Intr. Reply Function/Use (Adj. /normal/ 1. Status = Normal / long adjust the waveform mode. 5.6A long;T 2. Time = max waveform length in seconds normal = normal mode, Available times:...

  • Page 58: Examples Of Communication

    2. Description of the Cobia Cobia Communication Protocol 3. The CRC data value (16 bits) is then converted into Hex format (4 characters 0-9, AF). These four chars then replaces the four space characters. 4. Done! Technical info: If you want to implement this, it uses Standard CRC16 with CRC- polynomial P(x) = x , which correspond to hex code 0x8005.

  • Page 59: Standards And Compliances

    Equipment (WEEE) places an obligation on manufacturers, distributors, and retailers to take back electronics products at the end of their useful life. The WEEE directive covers all RTI products being sold into the European Union (EU) as of August 13, 2005. Manufacturers, distributors, and retailers are obliged to finance the cost of recovery from municipal collection points, reuse, and recycling of specified percentages per the WEEE requirements.
  • Page 60 2. Description of the Cobia Standards and Compliances Instructions for disposal of batteries by Users in the European Union The symbol, shown left, is marked on the battery, which indicates that this product must not be disposed of with other waste. Instead, it is the user's responsibility to dispose of the user's waste equipment by handing it over to a designated collection point for the recycling of batteries.

  • Page 61: Manufacturer's Declaration Of Conformity

    2. Description of the Cobia Standards and Compliances 2.7.3 Manufacturer's Declaration of Conformity Cobia - Reference Manual Version 2016.12A...

  • Page 62: Intended Use

    2. Description of the Cobia Standards and Compliances 2.7.4 Intended Use Cobia - Reference Manual Version 2016.12A...

  • Page 63: Fcc Certification

    WELMEC Guide 7.2, Risk Class C. The Type-examination Certificate number for Cobia is: DE-15-M-PTB-0005 If the Cobia is intended to be used for these legally regulated types of measurements in Germany, the user is referred to the corresponding German user manual for the Cobia.

  • Page 64: Maintenance

    No measurements are possible if a CRC error is found during system start-up. Such a system is also identifiable by special marking labels on the back of the Cobia (and Dose Probe), as shown below. Full descriptions of the different labels are given in the table further below.

  • Page 65: Updating The System

    2. Description of the Cobia Maintenance 2.8.2 Updating the System The Cobia system update can easily be done on any computer with support for USB memories. The update function is disabled on a german PTB system, please see the CRC Screen in section...

  • Page 66: Changing The Battery

    Maintenance 2.8.3 Changing the Battery The battery is a customized rechargeable battery that automatically charges when the Cobia is attached to a power source. It can only be replaced by RTI authorized service centers. Cobia - Reference Manual Version 2016.12A...
  • Page 67 Chapter 3 Measurement Principles & Theory...

  • Page 68: Measurement Principles & Theory

    3. Measurement Principles & Theory Measurement Principles & Theory The Cobia has a number of measurement algorithms and applications built-in. This section describes some about the principles, how some values are calculated, and the basic use of such measurements. Waveforms and Triggers To get an understanding of how triggers, delays, and windows work, take a look at the waveform below.
  • Page 69 2 second section. Tube voltage signal (kV, kVp) The Cobia measures two "different" tube voltages. 1. The integrated tube voltage (unit kV). This value corresponds to the standardized PPV method, which intends to give a value that independently of waveform gives the same image quality and dose contrast for a standardized phantom.

  • Page 70: Measurement Principle For The Cobia

    The D3 detector is positioned in the center of the cross in the middle of the round detector area on the top panel. The reference depth for the sensitive area of the dose detector is 8 mm under the round label on the Cobia top surface.

  • Page 71: Linearity

    1. Place the detector on the table-top. If patient-equivalent phantom should be used it is recommend to use the Cobia HVL stand to simplify the set up. Use 2 pieces of 10 mm Al filter as "patient -equivalent" filter in the beam.

  • Page 72: Reproducibility

    8. Calculate the square of the variance, i.e. the standard deviation, and divide it by the mean value of the n measurements An acceptable value for the coefficient of variation is less than 0.05. Cobia - Reference Manual Version 2016.12A...
  • Page 73 Chapter 4 Problems and Solutions...

  • Page 74: Problems And Solutions

    If the Cobia does not start, try the following: Connect the charger and retry starting the Cobia. If it does start, then the battery was too low to start. If this does not help, try resetting the Cobia as described below.

  • Page 75: Bluetooth

    1. Send a detailed problem report to support@rtigroup.com, describing what you did, what you got, and what you expected. 2. If Cobia is used together with the Ocean 2014 software, it is possible to send a problem report via the built-in function of the Ocean 2014 software. That will help us find the problem easier.
  • Page 76 Chapter 5 Glossary...

  • Page 77: Glossary

    5. Glossary Glossary In the HTML help version of the reference manual, you will find a radiology glossary. Cobia - Reference Manual Version 2016.12A...

  • Page 78: Index

    Dose Probe Specifications Indicator Dose probe typical energy response Passkey Dose/pulse Security code Doserate/pulse Bootloader Duty cycle - C - Duty cycle symbol Camera thread - E - CE Declaration Effective time Intended Use Version 2016.12A Cobia - Reference Manual...
  • Page 79 Minimum pulse det. ripple Screen cycling Minimum pulse width Signal source Minimum trig 35, 41 Source Status - N - Trig and screen cycling Negative Signal Intended Use Negative Signal error Internal detector settings Number of pulses Cobia - Reference Manual Version 2016.12A...
  • Page 80 Requirements, PC Number of pulses Reset Power Source Röntgen Unit Pulse frequency RöV (German X-ray Ordinance) Pulse rate Running time Pulse tube current Pulse width - S - Radiography Sampling rate 36, 42 Safety Precautions Version 2016.12A Cobia - Reference Manual...
  • Page 81 Voltage error Theory Current reading - W - Delay 64, 65 Dose rate reading Waste Batteries and Accumulators Irradiation time Waste Electrical and Electronic Equipment Waveform 64, 65 Linearity Waveform recording time Specifications Post delay Cobia - Reference Manual Version 2016.12A...
  • Page 82 Index Waveform resolution WEEE Weight WELMEC Guide Window Window time Version 2016.12A Cobia - Reference Manual...
  • Page 83 Notes NOTES Version 2016.12A Cobia - Reference Manual...
  • Page 84 Notes NOTES Cobia - Reference Manual Version 2016.12A...

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