Cabletron Systems BRIM F6 BRIM-F6 Specifikace

Clinical Neutron Therapy SystemInstallation and OperationsJonathan Jacky1Radiation Oncology, Box 356043University of WashingtonSeattle, WA 98195-6043T

D X terminal 111D.1 Host configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111D.2 Boot parameters . . . . . . . . . . .

5.6. TREATMENT HISTORIES AND ACCUMULATED DOSE SUMMARIES87The total doseclaimed in accum.datexceeds the product of the prescribed daily dose in accum.d

88CHAPTER 5. SUMMARY FILESThe control program works correctly in this situation; it only reads then number of lines claimed(219 in this example), and

5.7. STATISTICAL SUMMARIES891-JUL-1999 THROUGH 30-JUN-2000THERAPY MODETreatment days 212Treatment sessions 1485Treatment fields 3918Treatment runs (DM

90CHAPTER 5. SUMMARY FILESYear-Mo Patients Fields------- -------- ------1999-07 8 871999-08 12 731999-09 6 811999-10 10 1081999-11 2 571999-12 9 78200

Chapter 6Startup and shutdownThe control program is designed to run indefinitely. It is usually left running overnight and onweekends.These are the onl

92CHAPTER 6. STARTUP AND SHUTDOWNYou should not restart the control program by simply toggling the power or pressing the reset button(this does no har

6.1. STARTUP93It takes about 30 to 45 seconds for the X terminal to boot. While it is booting it displays a bluebackground screen and many messages sc

94CHAPTER 6. STARTUP AND SHUTDOWNIf the control program has succesfully completed its startup sequence, the lamp in the button turnsoff, indicating th

6.2. SHUTDOWN956.2.2 Shut down the control programYou can only shut down the control program at the X terminal.You can only shut down the program in e

96CHAPTER 6. STARTUP AND SHUTDOWNYou can only halt or crash the program in experiment mode when no run is in progress.

List of Tables1.1 Serial ports and controllers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42.1 Devices, IP addresses, and names on th

Chapter 7Interruptions and recovery proceduresIt should be possible to resume after any problem by restarting the control program (chapter 6.1),but in

98CHAPTER 7. INTERRUPTIONS AND RECOVERY PROCEDURES7.1.2 Determining how the program stoppedMessages on the console terminal can provide useful informa

7.2. TMC, LCC, OR DMC PROBLEMS997.1.4 Recovering after the program stops during a therapy runIf the program halts or crashes during a therapy run the

100CHAPTER 7. INTERRUPTIONS AND RECOVERY PROCEDURES7.2.1 Recovering after a DMC problem during a treatment runIf a DMC problem occurs during a therapy

7.5. HOST COMPUTER, FILE SYSTEM, AND NETWORK PROBLEMS1017.5 Host computer, file system, and network problemsThe control program continues running when

Appendix AHardware reference dataDevice Manufacturer and model numberControl computer Motorola MVME167-004B with a 25MHz 68040 processor and 32MB memo

Appendix BHost computerThe host computer provides remsh, tftp, time service, a font server and NFS. The host isconnected to the Internet so certain se

104APPENDIX B. HOST COMPUTERthis user, but it should not normally be necessary for any human user to log in as cnts. The cntsuser need not own any file

B.4. TRIVIAL FILE TRANSFER PROTOCOL (TFTP)105must contain an .rhosts file. The cnts user must have read permission for this file. The.rhosts file must co

106APPENDIX B. HOST COMPUTERThe time server is provided with most TCP/IP implementations ([15], p. 16). It is a standardcomponent of HP-UX 10.20. No s

4.12 Tolerances in tol.dat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 594.13 Description of files in /cntsdata/log/iso . . . . . . .

B.7. NETWORK FILE SYSTEM (NFS)107B.7 Network File System (NFS)The control program accessess its data files using NFS.To obtain authorization for using

108APPENDIX B. HOST COMPUTERshell (remsh) service, it is still necessary for the remote user to be authorized as described insection B.3 to execute a

Appendix CHubThe hub is a Cabletron MicroMACC-24E [2]. It provides connections for 24 devices. It was selectedand configured by Medical Center Informat

110APPENDIX C. HUB128.95.181.3 hub IP address255.255.255.0 subnet mask128.95.150.24 remote management platform IP address(known to MCIS staff) hub pas

Appendix DX terminalThe X terminal is am Tektronix model XP217C with 8MB of memory, a 17” color monitor, and aDEC LK401-style keyboard. Its control pr

112APPENDIX D. X TERMINALat the relative location given in the bpath boot parameter, /tekxp/boot/os.350. Thereforethe absolute path to the file is /cnt

D.3. TERMINAL SETUP113se monset select monitor settings... ( shows a menu of monitor settings)se monset 11 select setting 11 (1024x768 75Hz 17”)nvsave

114APPENDIX D. X TERMINAL1. Press the F3 key. A menu pops up.2. Select Setup.3. From the Configuration Summaries pull down menu, select X Environment.

D.4. BOOT PROCESS115This is the host IP address (the host name trombone will not work) and the port number for theX font server. This entry should app

116APPENDIX D. X TERMINALD.5 Tektronix X terminal boot parameters (summary)TekXpress Boot Monitor V5.58192 Kbytes memory installedHardware 08:00:11:04

List of Figures1.1 CNTS computers, terminals, and networks . . . . . . . . . . . . . . . . . . . . . . 34.1 Sample calfields.dat file . . . . . . . . .

D.6. TEKTRONIX X TERMINAL SETUP (SUMMARY)117D.6 Tektronix X terminal setup (summary)Press F3 to bring up the Setup Main Menu. Then selectNo window man

118APPENDIX D. X TERMINALD.7 Tektronix X terminal boot and startup messagesAttempting to boot with TFTP ...Requesting file ’tekxp/boot/os.350’ from IP

D.7. TEKTRONIX X TERMINAL BOOT AND STARTUP MESSAGES119When the terminal has successfully booted but the therapy control program is not yet running, th

Appendix ERoom displayThe room display is an ordinary PC with a 17-inch flat panel color display (Compaq Evo withTFT7020). It runs the Linux operating

1213. Add users:for F in cnts markwag jon dreid rislerdouseradd -m $Fpasswd $Fdone4. Enable telnet:Edit /etc/xinetd.d/telnetdisable = noonly_from = 12

122APPENDIX E. ROOM DISPLAY0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};8. S

Appendix FControl computer boot parametersSee section 3.5, pages 65 – 70 in [17].boot device :eiprocessor number :0host name :trombonefile name :/cnts

Appendix GConsole terminal setupWhen the control computer is reset, use to set boot parameters:baud rate 96008 bits per characterno parityone stop bit

Appendix HControl computer startup command file# isostart.192 - displays on private control network on 192.*.*.* subnet# isostart.65 - displays on .65

126APPENDIX H. CONTROL COMPUTER STARTUP COMMAND FILE# 3-Apr-2002 J. Jacky Fix daylight savings again to April 7 and Oct 27 2002# 29-Apr-2002 J. Jacky

1IntroductionThis document is the installation and operations manual for the Clinical Neutron Therapy System(CNTS), intended for cyclotron engineering

127taskSpawn "tUser",99,8,20000,user,4,"192.168.0.6:0","192.168.0.9","192.168.0.5","192.168.0.11:0"#

Appendix IControl computer boot and startupmessagesThese are the messages that appear on the terminal attached to the console port when the controlcom

129file name :/cnts/tftpdir/wind/mv167/vxWorksinet on ethernet (e) :192.168.0.7:ffff0000host inet (h) :192.168.0.10user (u) :cntsflags (f) :0x0target

130APPENDIX I. CONTROL COMPUTER BOOT AND STARTUP MESSAGES# - Directory for X windows .o files# - Directory for application .o file(s)# - Name(s) of ap

131trombone 192.168.0.10value = 0 = 0x0nfsAuthUnixShowmachine name = tromboneuser ID = 2200group ID = 70value = 19 = 0x13nfsDevShowdevice name file sy

132APPENDIX I. CONTROL COMPUTER BOOT AND STARTUP MESSAGES# Task will now run on the private control network -- 192.168.0.6# Next two IP addresses are

133TCP/IP socket open to Modicon PLC1Attempt #0:Connecting to Modicon 2 with a 10 second timeoutTCP/IP socket open to Modicon PLC2Returning from Open

Appendix JControl program log messages at startup01-JUL-1999 15:49:37 Starting01-JUL-1999 15:49:37 Log file /cntsdata/log/iso/iso1999-0701-154937.log,

Bibliography[1] Cabletron Systems, Inc., P.O. Box 5005, Rochester, NH 03867-0505. BRIM-E6 User’s Guide,1994.[2] Cabletron Systems, Inc., P.O. Box 5005

136BIBLIOGRAPHY[11] Scanditronix AB. Leaf collimator controller, LCC. In MC 50 Manual. Uppsala, Sweden,1984. Volume 9B, Part 9.6.[12] Scanditronix AB.

Chapter 1Computers and terminalsA block diagram of the CNTS control computers, terminals, and networks appears in Fig. 1.1.1.1 Control computerThe neu

1.1. CONTROL COMPUTER3CONTROL SYSTEM COMPUTERSXTERMINALPLC1 PLC2 DMC TMC LCC THERAPYCONTROL..HOST.PRIVATE NETWORKControl room Power supply roomDepartm

4CHAPTER 1. COMPUTERS AND TERMINALSPort Ctlr Description Configuration Jumper1 Console terminal DCE (DTE) J1 (J11)2 TMC Treatment motion controller DCE

1.2. CONTROLLERS5It is not necessary to set any switches or jumpers to set serial line characteristics (baud rate, parity,stop bits), these are all se

6CHAPTER 1. COMPUTERS AND TERMINALS1.3 PLC watchdogComponents external to the control computer (hardware and PLC) ensure that the control systementers

AbstractThis document is the installation and operations manual for the Clinical Neutron Therapy System(CNTS), intended for cyclotron engineering staf

1.5. ROOM DISPLAY7During routine operation the program should be run without a window manager, although it can rununder one.The control program reads

8CHAPTER 1. COMPUTERS AND TERMINALSfile and restart the control program. The control program reads the IP address of the room displayfrom the startup fi

1.7. DEPARTMENT COMPUTER CLUSTER9properly. After the control computer and X terminal have successfully booted, they can continue torun even if the hos

10CHAPTER 1. COMPUTERS AND TERMINALSon the cluster computers to update the control program prescription file.The control program is developed on the cl

Chapter 2NetworkThe control computer, PLCs, X terminal and host communicate over Ethernet hardware using theTCP/IP protocol. They are connected by a p

12CHAPTER 2. NETWORKDevice IP Address NameControl computer 192.168.0.7 elrondX terminal 192.168.0.6Host computer 192.168.0.10 trombonePLC1 192.168.0.9

2.3. HUB AND WIRING13Device PortControl computer (elrond) 4X terminal (therapy console) 9Room display 10Host computer (trombone) 19PLC1 (cyclotron, wa

14CHAPTER 2. NETWORKthe front of the hub faces up and the back faces down). For each socket there is a small green linklight LED on the front of the h

Chapter 3ConfigurationThe control computer and its program are adapted to their environment by setting boot parame-ters and providing a startup command

16CHAPTER 3. CONFIGURATIONThe vendor’s manual tells how to set the boot parameters (section 3.5, pages 65 – 70 in [17], alsosection 5.8, pages 361 – 3

c1998, 1999, 2001, 2002 by Jonathan JackyThis work may not be copied or reproduced in whole or part for any commercial purpose. Per-mission to photoco

3.3. STARTUP COMMAND FILE17After it has processed the startup command file, the target shell normally reads additional commandsfrom the console port. T

18CHAPTER 3. CONFIGURATIONThe command ld 1,0,"/cnts/tftpdir/vxwindows/support.o" loads the object fileof support functions provided with the

3.4. STARTUP PROCESS19maining messages are from the control program itself2. These messages include a listing of all tasksrunning on the control compu

Chapter 4Data files4.1 DirectoriesControl system data files appear in these directories on host computer:/cntsdata/data/iso Prescription file, accumulati

4.2. GROUPS214.2 GroupsThe pertinent groups are cnts (group number 103) and prism (group number 70). Those whoadminister and maintain the CNTS data fil

22CHAPTER 4. DATA FILES% ls -l /cntsdata/data/isototal 170-rw-rw-r-- 1 jon cnts 254 Apr 9 11:05 READ-rw-rw---- 1 jon prism 3030 Jul 9 09:14 accum.bak-

4.3. FILES IN/CNTSDATA/DATA/ISO 23code (in filenames.h). If any files are missing, or there are any additional files, or the ownershipor protection of a

24CHAPTER 4. DATA FILES14-JUL-1999 06:37:10 Dose cal file, open error at line 0that usually means the file is missing or has the wrong name or has the

4.3. FILES IN/CNTSDATA/DATA/ISO 25The following sections describe all of the files. The meaning of the file contents is described inmuch more detail in

26CHAPTER 4. DATA FILESFile Mode DescriptionREAD d Documentationaccum.bak w Copy of an earlier accum.dataccum.dat r,w Accumulated doses and fractionsc

Contents1 Computers and terminals 21.1 Control computer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21.1.1 Serial ports . .

4.3. FILES IN/CNTSDATA/DATA/ISO 27File Mode Read when ...READ d (documentation only, not read by CNTS software)accum.bak w (not read by CNTS software)

28CHAPTER 4. DATA FILESFile Mode Written when ...accum.bak w Patient is archivedaccum.dat r,w Run finishes in therapy modeWrite File at Fields screen i

4.3. FILES IN/CNTSDATA/DATA/ISO 294.3.5 accum.bakThe file accum.bakis a copy of accum.datwritten by the previewprescription viewer/archiverutility prog

30CHAPTER 4. DATA FILES4.3.6 accum.datThe file accum.dat records the accumulating fractions and doses for each field. The controlprogram displays the ac

4.3. FILES IN/CNTSDATA/DATA/ISO 31When a field is removed from prescr.dat, it must also be removed from accum.dat. Thisis the only time that a field sho

32CHAPTER 4. DATA FILESRestoring archived data to accum.datIt may happen that a therapist archives a patient by mistake before that patient has comple

4.3. FILES IN/CNTSDATA/DATA/ISO 33Timestamp recordThe timestamp record indicates when the file was last updated and other information about thecontents

34CHAPTER 4. DATA FILESPatient identification recordThere is one record to identify each patient. Each patient appears only once in accum.dat. Thecontr

4.3. FILES IN/CNTSDATA/DATA/ISO 35Field data recordThe second of the two field records contains the fractions and doses. All of the items in this recor

36CHAPTER 4. DATA FILESSeq. Contents Default1 Setting for leaves 0 – 19 in large calibration field -10.02 Setting for leaves 20 – 39 in large calibrati

3 Configuration 153.1 Boot parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153.2 Command interpreter (target shell)

4.3. FILES IN/CNTSDATA/DATA/ISO 374.3.8 colors.datThe colors.dat file stores the names of the colors used in the control program displays. It ispossibl

38CHAPTER 4. DATA FILES4.3.9 dosecal.datThe dosecal.dat file stores the dosimetry calibration constants that the program uses to calcu-late calibration

4.3. FILES IN/CNTSDATA/DATA/ISO 39Seq. Name Units Minimum Maximum Example1 DOSE RATE MU/min 0.0 99.9 60.02 TIME FACTOR 1.00 2.00 1.493 CAL GAIN 1 600

40CHAPTER 4. DATA FILES12-May-1999 risler## dosecal.dat## 5-Apr-1999 J. Jacky,R. Risler Change calvolt1,2 phys name and date# 12-Apr-1999 J. Jacky,R.

4.3. FILES IN/CNTSDATA/DATA/ISO 414.3.10 exper.datThe exper.dat file stores all the experimental studies and fields used in experiment mode.The control

42CHAPTER 4. DATA FILES4.3.12 keycodes.dat etc.The keycodes.dat file stores the keycodes for the keypad keys and function keys. Keycodesare stored in a

4.3. FILES IN/CNTSDATA/DATA/ISO 4316, /* PF1, refresh */126, /* PF2, help */103, /* PF3, msg_page */95, /* PF4, log_message */116, /* KP7, select_pati

44CHAPTER 4. DATA FILES4.3.13 message.datThe message.dat file contains the text that appears in the message of the day section of the helpscreen. To ch

4.3. FILES IN/CNTSDATA/DATA/ISO 45Lines Contents Minimum Maximum1 – 40 MINPOS for leaves 0 – 39 200.0 400.041 – 80 MAXPOS for leaves 0 – 39 0.0 200.08

46CHAPTER 4. DATA FILES4.3.15 oper.datThe oper.dat file contains the operator identification and the authorization that is checked whenan operator logs

4.3.12 keycodes.dat etc. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 424.3.13 message.dat . . . . . . . . . . . . . . . . . . . . . . . .

4.3. FILES IN/CNTSDATA/DATA/ISO 474.3.16 ports.datThe ports.dat file contains the leaf settings for the X-ray port film fields (useful ports are notexact

48CHAPTER 4. DATA FILES4.3.17 prescr.bakThe file prescr.bakis acopy of prescr.datwritten bythe previewprescription viewer/archiverutility program befor

4.3. FILES IN/CNTSDATA/DATA/ISO 494.3.18 prescr.datThe prescr.dat file contains all the patients and fields, including all the prescribed settings.This

50CHAPTER 4. DATA FILESRestoring archived data to prescr.datIt may happen that a therapist archives a patient by mistake before that patient has compl

4.3. FILES IN/CNTSDATA/DATA/ISO 51Name Units Minimum MaximumFRAC 0 99TOTAL MU MU 0.0 9999.9DOSE MU 0.0 999.8WEDGE TYPE 0 3WEDGE ROT 0 3LEAF 0 – 19 cm

52CHAPTER 4. DATA FILESPatient identification recordThe control program displays the items in this record on the patients screen. The patient name must

4.3. FILES IN/CNTSDATA/DATA/ISO 53Field identification recordIn this record the field sequence number is merely the sequence number within the block; ea

54CHAPTER 4. DATA FILESCode Wedge selection Code Wedge rotation0 No wedge 0 0 degrees1 30 degree wedge 1 90 degrees2 45 degree wedge 2 180 degrees3 60

4.3. FILES IN/CNTSDATA/DATA/ISO 55This record also shows the date the field was transferred from the treatment planning system intothe control system,

56CHAPTER 4. DATA FILESTreatment motion recordAt this writing only the turntable rotation angle and the gantry rotation angle are used by the controlp

4.5.4 Archived doses and fractions . . . . . . . . . . . . . . . . . . . . . . . . . 754.6 Files in /radonc/treatdata/cnts/log/iso . . . . . . . . . .

4.3. FILES IN/CNTSDATA/DATA/ISO 574.3.19 run.datThe run.dat file indicates when the control program may have crashed during a treatment run (atthis wri

58CHAPTER 4. DATA FILESSeq. Default Units Description1 5 seconds X server timeout (must be longer than file server timeout)2 5 seconds File server time

4.3. FILES IN/CNTSDATA/DATA/ISO 59Seq. Default Units Description1 0.10 cm Open leaves (difference between prescribed, actual)2 0.10 cm Closed leaves (

60CHAPTER 4. DATA FILES## tolerances file: open leaves, closed leaves, gantry, collim, turnt#0.150.200.50.70.7## pt_factor, press#0.011.0Figure 4.10:

4.4. FILES IN/CNTSDATA/LOG/ISO 61File Descriptiondmcyyyy-mmdd-hhmmss.dat DMC logsiso-dyyyy-mmdd-hhmmss.log Message logs written on demandisoyyyy-mmdd-

62CHAPTER 4. DATA FILESFile New file when ...dmcyyyy-mmdd-hhmmss.dat Write File at DMC screeniso-dyyyy-mmdd-hhmmss.log Write File at message log screen

4.4. FILES IN/CNTSDATA/LOG/ISO 63message like this:03-SEP-1999 12:40:31 File server responding, reading and writing filesagainIt indicates that messag

64CHAPTER 4. DATA FILES11 1 Square fields 9-87-85-66 4-Aug-9712 Selected by risler 0.0 0.013 Written by therapy control program21 12 large field, 1st

4.4. FILES IN/CNTSDATA/LOG/ISO 65It is possible that the control program may lose contact with the file server for some time (becausethe server is down

66CHAPTER 4. DATA FILESHere are three treatment records written during a run with no interruptions. A line-by-line descrip-tion follows.07-MAY-2002 09

5.7.1 Operating statistics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 885.7.2 Patient accruals and new fields . . . . . . . . . . . .

4.4. FILES IN/CNTSDATA/LOG/ISO 67Line 1: Record identification07-MAY-2002 09:38:38 Beam on - start of run| || Event typeDate, time record written in dd

68CHAPTER 4. DATA FILESLine 4: Dose, treatment time, flagsIn the beam-on and beam-off records, the fourth and fifth numbers are simply the accumulated d

4.4. FILES IN/CNTSDATA/LOG/ISO 69appear at the end of the field dose record in prescr.dat (section 4.3.18).Warning flag Description0 No warning1 Accumul

70CHAPTER 4. DATA FILESCode Description0 OK1 Pressure 1 unavailable2 Pressure 2 unavailable3 Pressure 1 outside range4 Pressure 2 outside range5 Press

4.4. FILES IN/CNTSDATA/LOG/ISO 71Line 6: Filter/Wedge60 deg 60 deg 90 deg 90 deg SMALL SMALL| | | | | || | | | | Actual flattening filter selection| |

72CHAPTER 4. DATA FILESLine 8-15: Leaves-3.50 -3.47 -3.00 -3.23* 0.00 0.01 0.00 0.01 0.00 -0.01| | | | | | | | | | || | | | | Leaves 2, 3, 4 prescribe

4.4. FILES IN/CNTSDATA/LOG/ISO 73Accumulating doses and fractionsIn each treatment run at least three treatment records are written (beam-on, beam-off

74CHAPTER 4. DATA FILES4.5 Files in /radonc/treatdata/cnts/data/isoThe /radonc/treatdata/cnts/data/isodirectory onthe department cluster contains arch

4.6. FILES IN/RADONC/TREATDATA/CNTS/LOG/ISO 75prescr.dat (section 4.3.18) at the time the archive operation occurred. The blocks appear in thearchive

Chapter 5Summary filesSeveral utility programs write files that can be useful for maintenance, troubleshooting, and qualityassurance. Some of these files

7.1.4 Recovering after the program stops during a therapy run . . . . . . . . . . 997.2 TMC, LCC, or DMC problems . . . . . . . . . . . . . . . . . .

5.1. AUTOMATION77You can get a quick look at how well the system has been running recently by executing the com-mand tail accum.err and so on for the

78CHAPTER 5. SUMMARY FILES01-May-2002 13:46:05 Prism fields appended to prescr.dat by montyThe new prescription data might contain one field or several

5.3. ARCHIVER SUMMARIES7909-Apr-2002 11:23:10 Archiving patient 3887 Karenina, Anna09-Apr-2002 11:23:12 Archived successfully09-Apr-2002 11:24:03 Arch

80CHAPTER 5. SUMMARY FILES5.4 Event log summaries5.4.1 eventlog.outAt this writing the file eventlog.out is always empty. The eventlog-cmdscript opens

5.5. TREATMENT RECORD SUMMARIES815.5.2 treatrec.errThe file treatrec.err is a cumulative summary of significant treatment record entries andother inform

82CHAPTER 5. SUMMARY FILESon follows another onoff does not follow onrun finished does not follow offTreatment records do not occur inthe expected seq

5.6. TREATMENT HISTORIES AND ACCUMULATED DOSE SUMMARIES83The therapy control program keeps an in-memory record of the accumulated total dose and numbe

84CHAPTER 5. SUMMARY FILESPatient 3957 Karenina, AnnaField 2 lt lat latFractions Daily Total TotalAcc Calc Meas Accum Calc8 8 90 720 720-- -- ----- --

5.6. TREATMENT HISTORIES AND ACCUMULATED DOSE SUMMARIES85in the run finished recorded (this is the “official dose for the run”). If the preset dose for

86CHAPTER 5. SUMMARY FILESline shows the number of lines, patients, and fields in the file. The numbers change from day to dayas patients and fields are