Topic ID: id_11038696
Version: 3.0
Date: Apr 22, 2019 12:55:20 AM

CT and PET Common Glossary

Table 1. Glossary
10-BASE2 or 5 or T100-BASE T	A 10BASE connection can transfer data between network computers at up to 10 Mbps. 10Base2 is thin coaxial and segments must be no longer than 185 m (607 ft). 10Base5 is thick coaxial and segments must be no longer than 500 m (1640 ft). 10BaseT is twisted pair wiring; use Category 5 or better.
A/D, ADC	Analog to Digital Converters are used to convert analog electrical signals to digital quantities.
ACAN	Axial CAN.
ACR/NEMA	American College of Radiology / National Electrical Manufacturers Association – an 'unbiased' organization that develops standards for electronic products.
ADF	Application Data Format.
AE Title	Application Entity is the DICOM name for a machine with a DICOM purpose on a network. The site's network administrator assigns a specific title to each application entity. You must carefully enter this information with the same capitalization as it is given to you.
AFOV	Axial Field of View
AIF	Axial InterFace.
AiM	Application integration Mechanism is a simple mechanism to enable new modules to share data and messages with older modules. The idea is to limit the interactions between the to-be-integrated application and the "integrated" ones. It is proposed as an efficient way to add new applications to the SdC platform, such as an existing Advantage Windows system. The design paradigm of AiM is referred to as weakly coupled design.
Air Cals	Air Calibration. This calibration is a series of scans that are taken of only air. The images are reconstructed and the CT numbers adjusted to give a number of -1000 for each pixel.
ALARA	As low as Reasonably Achievable (ALARA). Adult workers may receive a whole body dose 5 Rem per year; minors are restricted to 0.5 Rem per year; pregnant women are restricted to 0.5 Rem during the term of the pregnancy (for protection of the embryo). For comparison, actual physical effects (minor blood changes) from radiation exposure are not expected until a person receives 25 Rem in a short period of time. Higher eye and extremity doses are allowed because these have less effect than on that part of the body containing blood-forming organs.
ALM	Application Load Module.
AMD	Axial Motor Drive.
API	Application Programming Interface is the network software libraries or subroutines from which an application writer can call upon for various services.
APU	Attenuation Pipeline Unit.
ARP	Address Resolution Protocol is a network protocol that maps ethernet addresses to IP ones.
ASIC	Application Specific Integrated Circuit.
ASIR	Adaptive Statistical Iterative Reconstruction
AUI	Attachment Unit Interface. An IEEE 802.3 connecting the Media Access Unit (MAU) to the networked device. It also refers to the connector that attaches the host port to an AUI cable.
AW	Advantage Windows workstation is a stand alone image work station. The system is Sun Computer based and the software was developed in France.
AX-CAN	AXial CAN
Axial	Parallel to the z-axis; in the direction of the z-axis.
back projection	Mathematically summing and averaging all the data for a given pixel from every CT view during acquisition. The recon processor creates three dimensional voxels in two dimensions which eventually become the display image pixels. Given a filtered projection, this term refers to the process of smearing the projection back across an image matrix.
balun	RF impedance matching device.
bandwidth	The frequency range that contains the significant ultrasound content. It also describes the amount of data that a circuit or network can handle.
BGO	Bismuth Germanate, Bi4Ge3O12, a high density scintillation material, which, due to the high atomic number of bismuth (83) and its high density, is a very efficient gamma-ray absorber. Emits light at 400-600nm with peak at 480nm, with a primary decay time of 300ns.
BLD	Board Level Diagnostic
Block	An array of detector crystals (e.g. BGO) that are attached to a multiple anode PMT.
BOW	Beam On Window is the alignment of the X-Ray beam to the window on the detector.
bps	bits per second
bulkhead	The bulkhead refers to a panel where peripherals, laptops, modems, network can be connected.
bus	A parallel communications pathway composed of a group of wires, or of traces on a board or within a chip. The same bus can be used for different signals when tristate ICs are used because those not needed can be turned off; their output is changed to high impedance.
byte	A byte is eight bits numbered 0 through 7, bit 0 is the least significant bit (LSB). A byte is the smallest unit stored by a computer. Its location has one unique address.
Cam A, Cam B	Cams A & B are used to pre-patient collimate the x-ray beam.
CAN	Controller Area Network
CBF	Center Body Filter This is the alignment of the focal spot of the X-Ray tube to the center of the body filter in the collimator. This is the left/right alignment when looking at the gantry from the table.
CBT	Computer Based Training.
CCB	Collimator Control Board - Provides the electrical control to position the bowtie filter and the collimator Cams.
CCITT	Consultative Committee for International Telephone and Telegraph is an organization that sets worldwide voice and data communications standards.
CDCB	DAS Control Board on Merc40 detector.
CD-R	Compact Disc - Recordable. Write once compact disk.
CD-ROM	Compact Disc Read Only Memory is an off-the-shelf 4X CD-ROM drive. It is used to load software and play the Sherlock Operator's Manual.
CD-RW	Compact Disc - Re-Writable. Re-recordable compact disk.
CEM	Cassette Electronics Module - electronics which process incoming detector signals into digital data representing gamma photon arrival events (single events) at the detector.
CFC	Common Fan Controller
CFHC	Common Fan and Heater Controller
CFM	Clock Fanout Module - electronics used to drive precision clocks for synchronizing CEM's and the CPM.
CGI	Common Gateway Interface is an API developed for the Internet. A CGI could convert a WORD 6.0 document into a web page (HTML) or return user input on a web form to a WWW server or enable a computer to access the Internet through a firewall.
client	The computer or application that uses computer services provided by another computer or application. Each can then be optimized for their task.
CMOS	Complementary Metal Oxide Semiconductors are densely populated Integrated Circuits (ICs). They tend to need less power than TTL ICs. Nominal operating levels are 0 - 0.8 V for Low and 3.4 - 5 V for High. TTL compatible CMOS recognizes 2.4 V as High. CMOS chips are readily damaged by ESD.
console scan control	Scanner hardkey unit that is designed to sit above a standard workstation keyboard, incorporating scan and motion controls, radiation indicators and intercom. The system can either have a SCIM or GSCB.
control bus	A control bus carries signals used to initiate memory and data I/O operations.
CPM	Coincidence Processor Module - electronics which process single events from the CEM electronics to detect and localize simultaneous gamma photon arrivals at the detector (coincidence events).
CPU	Central Processing Unit.
CRC	Cyclic Redundancy Check
Cross Plane	An imaging plane created when coincidence events are accepted based on gamma ray arrivals in adjacent detector crystal rings (ring difference of 1). Hence a cross-plane is an image acquired for activity that lies between two detector rings. The axial acceptance angle of a cross plane can be opened up to include larger ring differences, where the ring differences accepted are always odd numbers.
CRT	Cathode Ray Tube. Video monitors made from CRTs are sometimes referred to as CRTs.
CT	Computed Tomography – a means of acquiring x-ray transmission measurements through a patient for the purpose of reconstructing a tomographic image of the patient's anatomy.
CT Scan Plane	The plane at the CT Origin that includes the x and y axes.
CTC	Coincidence Timing Calibration - used to reduce the spread in time pick-off variation between detector crystals and therefore permit reduction of the timing window.
CTS	Clear To Send. Serial control signal from the DCE.
CUP	Common Unix Platform is a foundational software library that CT and MR share. CUP monitor is used to control the most fundamental processes like the startup and shutdown of the scanner.
DA, D/A, DAC	Digital to Analog Converter.
daemon	A daemon is a UNIX background software process. The routing daemon maintains a routing table or database used to select the appropriate network interface when transmitting packets. This routing table contains a single entry for each route to a specific network or host.
DARC	Data Acquisition Recon Controller.
DAS	Data Acquisition System. The DAS is used to collect the data from the detector, convert it to digital, and send it to the Front End Processor.
DAS Channel	A detector channel consists of detector cells arranged in the Z direction.
DAS Count	Approximately 0.5 PPM (parts per million) of full scale. Equals one LSB (least significant bit) of DAS data word with largest FPA gain, i.e. exponent bits equal to 00 binary.
DAS Gain	DAS gain is actually preamp gain. It is a gain code defining the size of the integration capacitance. DAS gain is proportional to the inverse of the capacitance or gain code. DAS gain is set prior to scan. Lower gain code means less full scale signal, but better DAS electronic noise performance.
DASM	Data Acquisition System Manager. The DASM is the interface to a camera for filming the images. The DASM takes a single image and transmits it digitally or in analog form, depending on the type of DASM.
datagram	The smallest unit of network data
DCB	DAS Control Board. Controls DAS functions including sending digital DAS data to RF slip ring, and receipt and status back to the rest of the system.
DCD	Data Carrier Detect. Serial control signal from the DCE.
	Dual Channel Display.
DCE	Data Communication Equipment is an EIA term that refers to a digital device designed to emulate or provide a transmission connection, such as a modem. RS-232 signals move in one prescribed direction relative to the DCE or DTE.
DCM	DICOM Command Manager. The DCM is software that provides the Application Programming Interfaces (APIs) that implement DICOM tasks. A DICOM task initializes the DCM kernel on the AK server which will communicate with the remote DICOM station using DCM APIs.
DDC	Diagnostic Data Collection.
Detector Cell	The detector cell is the smallest element of the detector, consisting of a single photodiode.
Detector Channel	A detector channel consists of photodiodes arranged in the "Z" direction.
Detector FETs	Field Effect Transistors are used to select the photodiode combination of detector rows for post collimation slice thickness. The FETs are physically located on the detector assembly, but are controlled by the DCB (DAS Control Board). For 32-Slice Only: Field Effect Transistors are used to select the photodiode combination of detector rows for post collimation slice thickness. The FETs are physically located on the detector assembly, but are controlled by the DCB (DAS Control Board).
Detector Module	A group of detector channels, each channel divided into cells (also called a Pack).
DHC	Detector Heater Controller.
DHCB	Detector Heater Control Board.
DICOM	Digital Imaging and COmmunication in Medicine. DICOM is a computer file and protocol standard used by the medical imaging industry. It enables the transfer of data between various medical scanners and devices, regardless of manufacturer. The ACR (American College of Radiology) and NEMA (National Electrical Manufacturers Association, diagnostic imaging vendors) are working together to help make this evolving standard a reality. It is designed with PACs, Ethernet, networking type applications in mind so that information can be shared across electronic networks linking many kinds of computers. The practical emphasis has been on medical device manufacturers to conform so that their patient data from one particular modality are readable by computers, workstations, printers, medical scanning devices from many vendors. A DICOM task will initialize the DCM kernel on the AK server which will communicate with the remote DICOM client station using DCM APIs.
DIFB	Digital Interface Board.
DIG	Data Acquisition and Reconstruction Controller [DARC] / Image Generator [IG]
DIMM	Dual In-line Memory Module.
DIP	DAS Interface Processor. The DIP takes raw scan data from the slip ring and writes it to disk.
DIP Switch	Dual In-line Pin Switch. Small electrical switches, commonly packaged in blocks of eight and used on printed circuit boards.
Direct Plane	An imaging plane created when coincidence events are accepted based on gamma ray arrivals within a single detector crystal ring (ring difference of zero). Hence a direct plane is an image acquired for activity that lies in a plane centered on a detector ring. The axial acceptance angle of a direct plane can be opened up to include larger ring differences, where the ring differences accepted are always even numbers.
DMA	Direct Memory Access provides fast transfers between circuit board memory and its destination. The DMA controller relieves the CPU of managing I/O operations between RAM and disk or A/D devices. It is used to transfer completed axial images from the SRC to the OC.
DMB	Detector Memory Board.
DNS	Domain Name Service is a software protocol that translates Internet location names which are easier to remember to their IP addresses.
domain	The domain name identifies the machine/computer on a network.
DQA	Daily Quality Assurance
DRAGON	Display, Reconstruction And Graphical Operator iNterface
DRAM	Dynamic Random Access Memory
DSP	Digital Signal Processor is an integrated circuit (IC) that performs special function digital calculations.
DSR	Data Set Ready. Serial control signal from the DCE.
DTE	Data Terminal Equipment is an EIA term that refers to a digital device designed or configured to provide data, such as a computer or peripheral. RS-232 signals move in one prescribed direction relative to the DCE or DTE.
DTR	Data Terminal Ready. Serial control signal from the DTE.
DVD	Digital Versatile Disk. DVDs are optical media, similar to CDs, but capable of holding up to 4.7GB of data on a single sided, single layer disk.
DVD-RAM	Digital Versatile Disk - Random Access Memory. Recordable DVD.
ECL	Emitter Coupled Logic. ECL is a family of ICs used for high-speed signal transfer applications. It is faster than TTL. It requires voltages of -5 and -2 V which are labeled 5VN and 2VN. ECL differential signals are parallel terminated.
EDCAT	Event Detection, Coincidence And Timing subsystem – the old name for the RAPTOR subsystem.
EEPROM	Electronically Erasable Programmable Read Only Memory. The program stored in an EEPROM chip may be electronically erased. Consequently, EEPROMs are highly susceptible to ESD.
EIA	Electronic Industries Association is a US government department that provides the latest electronic related standards for engineers and manufacturers.
Elastomer	Rubber-like conductor of electricity.
EMC	Electro Magnetic Compatibility describes an electronic device that resists other and curbs its own electromagnetic influence.
EMI	Electro-Magnetic Interference.
EPROM	Erasable Programmable Read Only Memory uses ultraviolet light through a window on the chip to erase it.
ESD	ElectroStatic Discharge. Always use a known working (tested) wrist strap grounded to the unit before you touch any part with electronic components. There are several special grounding plugs on the frame for this. It is highlighted with a yellow icon label. Place the removed part in an anti-static bag or on a grounded pad. Protect it from further damage.
ETC	Enhanced Table Controller – single board computer in the table responsible for table motion control and management of hardkey inputs.
ethernet	Ethernet describes a hardware protocol for transferring data on a local area network (LAN). Ethernet cable can be coaxial, twisted pair or fiber optic.
Ethernet Address	Every system on an Ethernet network must have a unique Ethernet address. The physical Ethernet address of your system is the unique number assigned to the Ethernet board in the host. This unique number is assigned to the manufacturer of your Ethernet hardware by the IEEE (formerly by Xerox, one of the original developers of Ethernet). This is not to be confused with the IP address, which can be set arbitrarily.
Ethernet Switch	Connects the OC, ICE box, and gantry controllers together on the internal network.
FBP	Filtered Back Projection.
FEC	Forward Error Correction.
FES	Fast Ethernet Switch
FIFO	First In, First Out. A memory device in which the first piece of data stored in the buffer is the first removed; can be used as a buffer to align outputs.
firewall	A firewall is a computer that prevents unauthorized access to the network upon which it resides. A correctly configured internal computer can reach outside the firewall. See 'proxy.'
FORE	FOurier REbinning – a means of re-arranging 3D data into 2D sinograms for fast reconstruction using 2D methods.
FOV	Field Of View
FPA	Floating Point Amplifier. Auto-ranging gain stage between preamp and Analog to Digital converter on converter board. Gain from FPA is used to generate exponent portion of DAS data word.
FPGA	Field Programmable Gate Array is a standardized ASIC. It is a digital component that is designed and programmed to perform a specialized board function.
Frame	A set of sinograms collected simultaneously, typically one full axial field of view. If separate prompts and delayed sinograms are collected, each will be considered to be a frame. In normal 2D imaging, a frame consists of M direct plane sinograms and (M-1) cross-plane sinograms, where "M" represents the number of crystals in the axial direction. (Note: M = 24 for the 6x6 crystal block Discovery ST system.)
FRU	Field Replaceable Unit. A GE Acronym for items that can be replaced by field personnel.
ftp	File Transfer Protocol is a TCP/IP standard that is used to move files between computers on a network. It is particularly needed between dissimilar computers. It also describes Internet sites that use this protocol.
gateway	A gateway is a program or computer that handles moving data from one network to another. It often refers to communications between different kinds of networks. It handles client input and output for the server. The Gateway Host Name is also the AE Title.
GCAN	Gantry CAN
GDAS	Global Data Acquisition System. Obsoletes older Data Acq. Systems on LightSpeed 5.X scanners.
GND	Ground is used both as a signal reference and a power return path.
GRE	Global Recon Engine.
GSCB	Global Scan Control Box. Scanner hardkey unit that is designed to sit above a standard workstation keyboard, incorporating scan and motion controls, radiation indicators and intercom. GSCB replaces the SCIM on GOC6.6 and later.
GTCB	Global Table Control Board.
GTFR	Gantry Tilt Fan Relay Board
GUI	Graphical User Interface
HDIG	VCT HD Data Acquisition and Image Generator Computer Assembly
Helical Acquisition Modes	hi Speed mode, AKA 6 to 1 pitch (table travels 6 macro rows per rotation) hiQ mode, AKA 3 to 1 pitch (table travels 3 macro rows per rotation)
HEMIT	High Efficiency Motor Isolation Transformer.
HEPA	High Efficiency Particulate Air.
HIPAA	Health Insurance Portability and Accountability Act (of 1996).
hiQ	hiQ mode, AKA 3 to 1 pitch (table travels 3 macro rows per rotation).
HIS	Hospital Information System describes a computer system that retrieves and stores patient personal data and their diagnostic images on a network.
HSDCD	High Speed Data Capacitive Device.
HSS	Heat Soak and Seasoning.
HSSD	HiSpeed Scan Data Disk is used for saving raw data as it comes from the DAS.
HTML	HyperText Markup Language is an Internet standard that decrees how a web page should be tagged in order to display information as intended or to go to another place on the Internet or to start a particular function. HTML is evolving. It is readable by both computers and people.
HTTP	HyperText Transfer Protocol is an information serving protocol that helps make the Internet possible because it is generic, stateless and object oriented means to transfer files.
HV	High Voltage.
HVDC	High Voltage DC (Direct Current).
hypertext	Hypertext describes the kind of information that the Internet supplies; beside text, there are sounds, voice recordings, maps, pictures, animations, videos, 3D simulations, live interactive games and conversations, links to other information sources.
ICD	Inspection Certification Document arrives with new equipment. It is used to prove the unit was tested. A SHIPMENT and INSTALLATION card accompany it. They are submitted to headquarters upon those events to track the location of the unit.
ICMP	ICMP is the error and control message protocol used by the Internet protocol family. It is used by the kernel to handle and report errors in protocol processing. It may also be accessed through a 'raw socket' for network monitoring and diagnostic functions. ICMP is used internally by the protocol code for various purposes including routing, fault isolation, and congestion control. Receipt of an ICMP redirect message will add a new entry in the routing table or modify an existing one. ICMP messages are routinely sent by the protocol code.
IF or I/F	Interface. An interface is a circuit needed to connect either two different devices or families of circuits. It solves a problem. An interface may prepare and protect circuits; it may decode, deliver, translate signals.
IG	Image Generator
IMS	Information Management System.
Insite Modem	Data communication device.
IP	Internet Protocol. IP describes globally used computer communications applications like ping, telnet, and ftp. These are not specific to Ultrasound or GE Medical Systems. IP is the internetwork datagram delivery protocol that is central to the Internet protocol family. Programs may use IP through higher-level protocols such as the Transmission Control Protocol (TCP) or the User Datagram Protocol (UDP), or may interface directly using a "raw socket." 'pings' have an IP and ICMP header.
IP Address	Every computer on the Internet has a unique IP Address consisting of four 8 bit integers (bytes) separated by dots. Each part can be number from 0 to 255. One portion identifies the host and another the network. That portion can be from one to three contiguous parts. IP Address allocation is managed by a central authority.
IPC	Inter Process Communication. IPC is the exchange of data between two software processes, either within the same computer or over a network. It implies a protocol that guarantees a response to a request. Examples are Unix sockets, RISC OS' messages and Microsoft Windows' DDE.
ISDN	Integrated Services Digital Network is a telecommunication media that US phone companies are beginning to offer. It transfers data through existing phone lines five time faster than V.32bis modems.
ISO Alignment	ISO Alignment is the alignment of the focal spot of the tube to the center channel of the detector. This alignment is left/right when viewing the gantry from the table.
K&R	Kinahan & Rogers - 3D reconstruction algorithm using filtered backprojection of views to reconstruct images.
kernel	Describes the portion of a computerized machine that controls it. Sometimes it means the hardware, the Central Processing Unit (CPU), that controls all the Input/Output (I/O) and coordinates the operation of all hardware; sometimes it means the software that does this. Since it involves both, one cannot do its job without the other, kernel really means the controlling hardware and software.
Keyboard	Input device.
LAN	Local Area Network. A network for transferring data or images that is confined to a small area. Usually within the same building.
LCC	Low Cost Country (HP Table made in China)
LFC	Load From Cold. "Cold" Software Load Procedure.
LIFO	Last In, First Out.
LSB	Least Significant Bit. Bus names include the number of signals that comprise that bus. The number that appears after the colon is the LSB of that bus. The following example has eight signal lines. EXAMPLE: BUSNAME(7:0)
malloc errors	This is a fatal situation for software; if it could not correctly allocate memory space for an operation, the system cannot continue.
MBP	Mean Beam Position.
MDAS	Millennium Data Acquisition System. MDAS allows 4-slice or 8-slice operation.
MDAS 16	Millennium Data Acquisition System. MDAS 16 allows 16-slice operation.
mean	The arithmetic average of all values in a set.
MFM	Message Format Manager. MFM is the AKSERVER (software) component that translates data to DICOM format so that it can be sent to another DICOM device on the network.
MNP	Microcom Networking Protocol compresses uncompressed files as they are transferred through a modem.
MOD	Magneto Optical Disk. MOD is a storage device that can be recycled. It's used to store system software, files and images.
modem	Device used to transmit digital information across phone lines. It is an abbreviation for Modulator-Demodulator.
mouse	Input device.
MSB	Most Significant Bit. Bus names include the number of signals that comprise that bus. The number that appears before the colon is the MSB of that bus. The following example has eight signal lines.
MSD	Means and Standard Deviation
MSDS	Material Safety Data Sheet
MSUB	Milwaukee SUBordinate board. Signal routing for the TGP.
MTCB	Milwaukee Table Control Board.
MTM	Message Transfer Manager. A DICOM term.
MTU	Maximum Transmission Unit. Internet datagrams can be fragmented and reassembled during their transmission. If the datagram is larger than the maximum transmission unit of the network, it is fragmented on output.
MUX	Multiplexer selects one of multiple inputs to be routed to one output.
Name	For the network configuration, the DICOM Archive or Print application's name must be entered exactly as the site's network administrator has named the DICOM device, so that all software on the network can properly recognize it. One device can have more than one DICOM application so there can be more than one Name and AE Title associated with any particular DICOM computer.
NC	No Connection describes an electrical interface.
NDIS	Network Device Interface Specification describes 3Com and Microsoft drivers needed to make TCP/IP networking happen.
Net Mask	A Net Mask is an IP Address filter that eliminates communication/noise from network devices of no interest to your machine
Netscape	Software that displays electronic words, sounds, pictures, that have been put in htm, HTML, gif, mpeg format, meaning it adheres to the http protocol.
Network Interface	Connection from local unit to network.
Network Type Support	100BASE T describes the speed and hardware that can be used to connect computers.
NFS	Network File System describes a computer system that can use or supply other computer systems even if they are dissimilar. NFS consists of client (user) and server (supplier) systems. An NFS server can export local directories for remote clients to use. A NFS client can then use those remote files.
NIS	Network Information Services is an NFS service that supports distributed databases for maintaining administrative files for the network, like passwords, host addresses. NIS provides a centralized database of information about systems on the network. This service can be used to look up the hostname or IP address of a particular system on the network.
NVRAM	Non Volatile Random Access Memory is used to hold important system info.
OBC	On Board Controller - The gantry controller for CT functionality on the rotating side of the structure.
OC	Operator’s Console.
ORP	On-board Rotating Processor. Controller on rotating portion of gantry.
OWS	Operator's WorkStation - synonymous with PET Host, or DRAGON Host
packet	A packet is a group of binary digits representing data and control which is sent in a well defined format over a network.
PARC	PET Acquisition Reconstruction Controller
partition	A disk partition can be used as a file system, a logical volume, or raw disk space.
PB	Power Board on Merc40 detector
P-Cal	Phantom Cal. The phantoms are made of water (CT# 0) or teflon (CT# ~100). Large medium and small phantoms are scanned and the images generated. Then an adjustment is made to give each pixel the correct CT#. This is applied to all images scanned.
PCI	Peripheral Component Interconnect.
PDU	Power Distribution Unit.
PET Reference Plane	The plane at the PET Origin that includes the x and y axes.
PLD	Programmable Logic Device is also an ASIC.
PM	Planned (or Periodic) Maintenance.
PMC	PCI Mezzanine Card
PMT	PhotoMultiplier Tube
POR	Plane Of Rotation. This is the physical alignment of the focal spot of the tube with the aperture of the collimator. The alignment is towards or away from the table.
port	For network configuration, enter the number that the administrator has assigned for the DICOM application.
PPE	Personal Protection Equipment.
PPP	Point to Point Protocol enables a computer to access a network with a telephone, a fast modem and a service provider.
Preamp (preamplifier)	Amplifier on the converter board that integrates the current signal from the detector. Also serves as anti-aliasing filter before analog to digital conversion of the signal from the detectors.
PROM	Programmable Read Only Memory is programmed by burning fusible links inside the chip. Once burned, they cannot be changed.
protocol	A recipe of software, parameters and settings that will enable two computers to communicate.
proxy	A network proxy enables a computer user to communicate across a firewall of an intranet whose access from the outside world is guarded by that firewall. Business employees need to configure their web browser software proxies for various protocols used to access Internet information is various ways, http being the most common. Home users who have an independent service provider do not need or use proxies.
RAD	Roentgen Absorbed Dose
Radial Alignment	Radial Alignment This is the alignment of the detector so that both ends are equidistant from the focal spot of the tube.
RAM	Random Access Memory
RAPTOR	Realtime Acquisition of Photon Trajectory Of Response
RCIB	Rotating Controller Interface Bus.
RCOM	Rotating COMmunications
reconfig	A shell started program with a GUI that changes system parameters.
RHARD	Reset Hard Signal
register	A digital, electronic device for temporary storage of a value.
REM	Radiation protection specialists (or health physicists) use meters to determine radiation levels. Radiation levels are normally (in the US) measured in Roentgens/hour (R/hr). The Roentgen is a unit of radiation exposure. The Rem (Roentgen Equivalent Man) is the unit of Dose (actually absorbed taking biological effects into account). The Rad (Roentgen Absorbed Dose) is simply the actual amount of radiation absorbed. The two are related by the relationship: Rem = Rads x Quality Factor (QF)
Removable Media Drives	Disk drives in which the media can be removed. For example: MODs, floppy disks and CD-ROMs.
repeater	A network repeater is a device to connect two or more devices to a subnet; the last port on a repeater can be used to connect multiple hubs. A repeater conditions the signal and with the hub port can extend the physical distance between devices. This is important because there are limits to how far a cable length can be effective.
REQ	Request signal.
RF Ring	Communication channel to passes raw image data from the rotating side of the gantry (MDAS) to the stationary side.
RF Shoe	Picks up the RF signal from the RF ring.
RIS	Radiology Information System describes a computer system that retrieves and stores patient personal data and their diagnostic images on a network. Some of these RIS systems are compatible with the CT system. When the host application called Worklist Server, or WLServer, conforms with the RIS, then that patient data can be shared across the network.
ROI	Region Of Interest
ROM	Read Only Memory.
router	A router is a device that determines what path network traffic will take to reach its destination. It extends a local area network (LAN) to create a larger inter-network. It uses the routing information inside the data and the criteria programmed into it to make decisions on how to most efficiently route the data.
RS-232	Electronic Industries Association (EIA) standard for serial data transmission that prescribes signals by voltage level and pin location.
RS-422	EIA standard for the serial exchange of digital data between two pieces of electronic equipment that uses a balanced, or differential, interface. It uses relative differences between a positive and negative signal without reference to a common ground. This enables greater speed and immunity to noise or EMI.
RTS	Real Time Statistics.
RTS	Request To Send. Serial control signal from the DTE.
SBC	Single Board Computer.
SCIM	Scan Control Intercom Module – scanner hardkey unit that is designed to sit above a standard workstation keyboard, incorporating scan and motion hardkeys, radiation indicators and intercom.
SCORP	Smart Cathode Onboard Rotating Processor
SCOM	Stationary COMmunications.
SCP	Service Class Provider describes a DICOM task/device that allows other devices on the network to query the SCP for images or data. A SCP task listens on the specified port for the Application Entities (AE) that it has been configured to hear. SCP is like a server.
SCSI	Small Computer System Interface is a peripheral interface standard commonly used for hard disk drives and some printers to speed up data transfer.
SCU	Service Class User describes a DICOM task/device that uses another unit on the network to store or print images or get patient information so that the technologist does not have to key it in. SCU is like a client
SDD	Scan Data Disk. Hard drive that holds scan data.
SDDA	Scan Data Disk Array.
SDM	Service Desktop Manager. Graphical User interface used to access service related tools and functions.
SDRAM	Synchronous Dynamic Random Access Memory.
Septa	Septa are tungsten plates that are placed between the physical rings of detector crystals (so they're shaped like flat donuts) in order to stop out-of-plane photons. Used in 2D imaging to reduce scatter and randoms. There is one septum between each pair of rings. A collimator is the full set of septa.
server	A server is a computer system or application that provides the programs and disk space that a client computer or application possibly somewhere else on the network uses. The communication link between a server and client is called a socket.
SFOV	Scan Field Of View
SHARC	Sorter, Histogrammer, Acquisition, and Reconstruction Controller
SI	SI unit for dose (Sieverts) is used (1 Rem = .01 Sieverts).
SMPTE	Society of Motion Picture and Television Engineers.
socket	The software structure that enables a communication link between any two network computer processes, like a server and client, is called a socket. You need an IP address and a port to establish a socket. The verb 'bind' is often used in connection to socket.
Software Level - Application	Applications Level is the software level where the scanner specific software has been initialized and the system could be used to: scan, archive, display, film, etc.
Software Level - Boot	Boot level is where no software is running other than what can be run out of CPU firmware. This was often referred to as 'PROM Monitor' or 'Boot Prompt' or Single User Mode.
Software Level - Operating (Irix)	Operating is the software level in between 'Boot Level' and 'Applications Level'. This is often referred to as the Operating System level. The system will normally start and login as user 'ctuser' leaving the User Interface ready for selection of Irix and Unix Commands or start-up of the Scanner Applications Software.
SOP	Service Object Pair. A DICOM software term. Server Object Pair is Service Class User plus Service Class Provider. Client/Server
SRC	Slip Ring Communications.
subnet	A subnet is a group of connected computers or hosts. The network portion of their IP addresses would match, but the host portion would be unique.
System State	Program available on Service PM menu that enables you to save and restore protocols, calibration, configuration, Auto Voice, Display Preferences, and characterization of the Table, Gantry, and InSite features.
TCP	Transmission Control Protocol (software) assumes the datagram service it is layered above is unreliable. A checksum over all data helps TCP implement reliability. Using a window-based flow control mechanism that makes use of positive acknowledgments, sequence numbers, and a retransmission strategy, TCP can usually recover when datagrams are damaged, delayed, duplicated or delivered out of order by the underlying communication medium. If the local TCP receives no acknowledgments from its peer for a period of time, as would be the case if the remote machine crashed, the connection is closed and an error is returned to the user. If the remote machine reboots or otherwise loses state information about a TCP connection, the connection is aborted and an error is returned to the user.
TCP/IP	Transmission Control Protocol/Internet Protocol is a common standard for transferring data across the Internet.
telnet	Telnet is another TCP/IP standard. Telnet is a protocol that enables your computer to logon to a remote computer and query that computer for its information or use its programs.
TGP	Table Gantry Processor. Gantry stationary processor.
TGPU	Table Gantry Processor United with MSUB. TGP combined with MSUB.
TNC	Table Network Controller - interface process between the Enhanced Table Controller (ETC) and the CAN bus interface to the gantry hardkeys and displays.
TPO	Timing PickOff
Transaxial	A plane that is normal to the z-axis; a line or direction that is perpendicular to the z-axis.
T-Ring	Transmission ring encoder signal, used to determine the position of the line source during a normalization or transmission scan.
Trolley	Platform that carries the PET gantry support plate, detector, source loader and drive, and RAPTOR so they can be moved for service access.
TTL	Transistor to Transistor Logic is low with voltage levels from 0 to 0.8 V, and high at levels of 2.4 to 5 V. This is also called Vcc, digital logic, and 5V.
TxD	Transmitted Data. Serial data from the DTE to DCE. It is serial data from the host to a peripheral or modem.
TXXT	Trigger On, X-Ray On, X-Ray Off, Trigger Off
UDP or udp	User Datagram Protocol. UDP is a network term.
UID	Unique IDentifier
UPS	Un-interruptible Power Supply.
URL	Uniform Resource Locator is a way to define a resource location on a network. It describes the type of service (http, ftp, or telnet, and its exact location by network, if different, its directory and its file name. Format: protocol://computer[:port]/path/filename Example: http://www.gemedicalsystems.com
V.34	A CCITT standard for modem communications that extends the V.32 connection rate to 28.8 k bps. With data compression, this rate can theoretically go to 115.2 kbps but the condition of most phone company links prevents that from happening. This standard was previously known as V.Fast and V32terbo.
V.42	A CCITT standard for modem communication that improves throughput by correcting errors and compressing data.
VDARC	VCT Data Acquisition Recon Controller.
VDIG	VCT Data Aquisition and Image Generator Computer Assembly
VERB	Volume Reconstruction Box
V.Everything	A CCITT standard for modem communications that improves throughput by adapting to the modem to which it connects and using optimal protocols.
VLSI	Very Large Scale Integration of electronic circuits on one chip.
VVC	Views Versus Channels
WORM	Write Once, Read Many.
X Window	X Window is a windowing system developed at MIT, which runs under all major operating systems.
Y/C	An abbreviation for a composite video signal that carries color, sync and brightness information. The Y portion - called luminance - carries the sync and brightness and can be used for black and white as well as color video. The C signal - called chrominance or chroma - carries color information, and synchronizes with the horizontal frequency.
Z-Alignment	After changing a tube, both the BOW (beam on window) and POR (plane of rotation) need to be done. Since the collimator and detector have not changed position, the X-Ray tube only needs to be adjusted toward or away from the table. (Assumes the collimator and detector are in the correct position.) The Z-Align can do this with one adjustment instead of two.
Z-CHANNELS	DAS channels used to control "Z" direction centering of beam on detector via the collimator. Have special detector FET control lines, to select outer detector cells.