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How to Make the Final MU Check Occur After the Last Human Intervention in an Electronic Chart Alan Kepka Northwestern Memorial Hospital.

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Presentation on theme: "How to Make the Final MU Check Occur After the Last Human Intervention in an Electronic Chart Alan Kepka Northwestern Memorial Hospital."— Presentation transcript:

1 How to Make the Final MU Check Occur After the Last Human Intervention in an Electronic Chart Alan Kepka Northwestern Memorial Hospital

2 Initial physics check performed by an independent observer to verify the Tx plan against the Rx, appropriateness of the plan, correctness of MU calculation and accuracy of transfer of data to the paper Tx record. In the Days of Paper Tx Records Tx plan or MU calc on paper & part of paper Tx record. Paper Tx Record Rx Beam parameters MUs Data Transfer by Dosimetry / Physics

3 Initial physics check performed by an independent observer to verify the Tx plan against the Rx, appropriateness of plan, correctness of MU calculation and accuracy of transfer of data to the paper Tx record and the RV System. In the Early Days of Record and Verify (RV) Tx plan or MU calc on paper & part of paper Tx record Paper Tx Record RV System Rx Beam parameters MUs Data Transfer by Dosimetry / Physics

4 Radiation therapists mechanically set Tx table and beam parameters, “thumbed” in MUs and recorded Tx in a paper record. ( ). Electronics captures mechanical parameters and delivered MUs and recorded this information in the RV System. ( ). The Workings of Early RV Systems Paper Tx Record RV System Rx Beam parameters MUs

5 For Current Technology (circa. 2006) the Following Processes Occur. Tx Planning System RV System Stores Tx Script & Records Tx Linear Accelerator The Tx planning computer downloads data to the RV System which now replaces the paper chart’s function to store and display Tx setup notes, machine parameters and MUs to be delivered (Tx script). The RV System downloads beam parameters and MLC shapes to the linac. The radiation therapists set Tx parameters that the linac cannot set automatically. The RV System records all mechanical parameters and the delivered MUs after the Tx has been completed.

6 Initial physics check performed by an independent observer to verify the Tx plan against the Rx, appropriateness of plan, correctness of MU calculation and accuracy of transfer of data to the RV System. For Paperless Tx Scripts Tx plan or MU calc on paper & part of paper …Tx record. & RV System RV System Rx Beam parameters MUs Data Transfer Computer DICOM RT

7 A Complication Introduced by DICOM RT DICOM RT does not consider bolus as a RT structure For wedged tangential breast fields with bolus a.Perfect Tx plan with bolus b.Calculate without bolus c.Transfer beam parameters from ADAC to IMPAC d.Calculate with bolus e.Adjust MUs in IMPAC to reflect the us of bolus

8 For Paperless Tx Scripts Tx plan or MU calc on paper & part of paper …Tx record. RV System Rx Beam parameters MUs Data Transfer by Computer DICOM RT MU Adjustments Dosimetry / Physics

9 A Complication Introduced by DICOM RT and Elekta’s Motorized Wedge Leads to Double Trouble Elekta’s MUs are a two component vector Representation 1: Magnitude (Total MUs) and Direction (Wedge Angle) Representation 2: Open MUs, Wedged MUs Representation 3: Total MUs, Wedged MUs

10 Relationship Between Representations Wedged Dose / Total Dose = TAN (Wedge Angle) / TAN(60 o ) Wedged MUs = k* (Wedged Dose / Wedge Factor) Open MUs = k* (Total Dose – Wedged Dose) where k = f(SSD, TPR, Output factor…) Wedge Factor ~ 0.25 (6X)

11 Tx Field Parameter Page in IMPAC

12 Representation 3 used by ADAC, IMPAC and Elekta Wedge ~20 o If Wedge angle = 60 o, then Total MU = 189 and Wedge MU = 189 for example. But if Wedge MU was not manually entered, then delivered dose would be ~ 4 times the prescribed dose. NOT GOOD!!

13 To Catch MU Vector Entry Errors Strategy 1. For wedged fields, have 2 nd. independent physics review.. Measure entrance dose and. compare with expected result. Strategy 2. Electronically confirm the. correctness of the MU vector. entry in the electronic Tx script. after all human interventions. have occurred.

14 Developed Strategy 1 First Due to Expediency Distinct spreadsheets contained in distinct folders for each X-ray energy

15 Data entered manually in aqua- marine cells

16 Expected Entrance Dose Diode Readings and Range Expected Diode Readings +/- 10 % Range Distance from CA to diode placement point

17 Example of Diode Readings Acceptable Agreement +/- 10% window for diode readings Overall weighted and individual beam agreement +/- 4% Note: Okay* if the error for the field is >4% but less than 2% of the total dose

18 Rational for Developing Strategy 2

19 Existing MU Calc Check Spread Sheet No ADAC IMPAC LINAC PATIENT Tx Yes Approve Fields Investgate No MU Check Calculation Does Adac / Spread Sheet Data match IMPAC? Agreement? Computer Transfer Human Transfer

20 Existing MU Calc Check Spread Sheet No Error in data entry ADAC IMPAC LINAC PATIENT Tx Yes Approve Fields Investgate No MU Check Calculation Does Adac / Spread Sheet Data match IMPAC? Agreement? Computer Transfer Human Transfer

21 Existing MU Calc Check Spread Sheet No Computer Transfer Human Transfer ADAC IMPAC LINAC PATIENT Tx Yes Approve Fields Investgate No MU Check Calculation Does Adac / Spread Sheet Data match IMPAC? Agreement? Error in data entry Error in comparison of data

22 Existing MU Calc Check Spread Sheet No Incorrect treatment Computer Transfer Human Transfer ADAC IMPAC LINAC PATIENT Tx Yes Approve Fields Investgate No MU Check Calculation Does Adac / Spread Sheet Data match IMPAC? Agreement? Error in data entry Error in comparison of data

23 New MU Calc Check Spread Sheet (1/30/06) Agreement? Computer Transfer Human Transfer Approve Fields Yes ADAC IMPAC LINAC PATIENT Tx No MU Check Calculation

24 New MU Calc Check Spread Sheet (1/30/06) Agreement? Computer Transfer Human Transfer No ADAC IMPAC LINAC PATIENT Tx MU Check Calculation Investigate

25 How the system works: The user creates the Txfield.xls file from IMPAC This file is stored in C:\Windows\Temp The user clicks on the shortcut to the ADAC_IMPAC Folder, And the then activates the SL15_AllX_Adac_IMPAC_001.xls spreadsheet. The spreadsheet reads in the Txfield.xls file and does preliminary calculations including the “best” wedge angle. The user enters additional data in the gray areas as required, clicks the “Best” wedge angle if required and Exports the resulting data. The data is transferred as pure data (no formulas, no code) to the Spreadsheet Blank.xls. The user then clicks the Save button and Prints the spreadsheet. And then exits EXCEL without saving any additional files.

26 Developing Strategy 2 - Step 1 =IF(B$16>=100,100*pdd(B16,C16,C17,. B17,B25,B26),tar(B26,B17)/bsf(B26)) =TF(C21) Create one spreadsheet for all X-Ray energies.

27 Typical Functions Affected TF(id) Tray Factor  TF(nX, tray) Opf(s)Output Factor Fsf(SSD, s, opf)Field Size Correction Factor BSF(s). Sc(s). Sp(s). TAR(s, depth). TPR(tar, bsf). PDD(SSD, depth, s, …). Wed60a5(s) Wedge Transmission Factor Oawdgfctr(SSD offaxis, Depth offaxis, OAD depth ) Off-Axis Wedge Transmission Factor id, tray = identification of tray s = equivalent square field OAD depth = Off-Axis distance at Depth nX = beam energy id number

28 The Most Complicated Function to Restructure = IF(B$16>=100,100*pddA(C11,B16,C16,. C17,B17,B25,B26),tarA(C11,B26,B17) /. bsfA(C11,B26))

29 Function pdd04(nX, SSD, d, SSDoffaxis, Doffaxis, s_open, s_eff) DMax = dMax1(nX) s_d = s_eff * ((SSDoffaxis + Doffaxis) / 100) s_dmax = s_eff * ((SSD + DMax) / 100) tar_d = tar04(s_d, Doffaxis) bsf_dmax = bsf04(s_dmax) tpreff = tar_d / bsf_dmax If tpreff > 1 Then tpreff = 1 End If pdd04 = tpreff * ((SSD + DMax) / (SSDoffaxis + Doffaxis)) ^ 2 End Function Function pddA(nX, SSD, d, SSDoffaxis, Doffaxis, s_open, s_eff) If nX = 1 Then pddA = pdd04(nX, SSD, d, SSDoffaxis, Doffaxis, s_open, s_eff) If nX = 2 Then pddA = pdd06(nX, SSD, d, SSDoffaxis, Doffaxis, s_open, s_eff) If nX = 3 Then pddA = pdd10(nX, SSD, d, SSDoffaxis, Doffaxis, s_open, s_eff) If nX = 4 Then pddA = pdd18(nX, SSD, d, SSDoffaxis, Doffaxis, s_open, s_eff) End Function Structure of pddA & pdd for One Beam Energy

30 Dim dMax1(4), TFM(4) Sub Initialize() dMax1(1) = 1.2: dMax1(2) = 1.5: dMax1(3) = 2.4: dMax1(4) = 3# TFM(1) = 1.058: TFM(2) = 1.045: TFM(3) = 1.042: TFM(4) = End Sub Auxiliary Code Utilized by pddXX(…) Implication of indices for depths of dMax and basic tray factors (1/Tray Transmission) versus beam energy index 1 => 4X = 4 MV 2 => 6X = 6 MV 3 => 10X = 10 MV 4 => 18X = 18 MV Beam Energy Index

31 How to Retrieve Data from Electronic Record Click on Import Data Button Sub Read_Impac_File() ChDir "C:\WINDOWS\Temp" Workbooks.Open Filename:="C:\WINDOWS\Temp\txfield.xls" Columns("A:R").Select Selection.Copy Windows("SL15_AllX_Adac_IMPAC_002.xls").Activate.

32 How to Retrieve Data from Electronic Record Sub Read_Impac_File() ChDir "C:\WINDOWS\Temp" Workbooks.Open Filename:="C:\WINDOWS\Temp\txfield.xls" Columns("A:R").Select Selection.Copy Windows("SL15_AllX_Adac_IMPAC_002.xls").Activate ActiveSheet.Unprotect ''Temporary Columns("AE:AV").Select ActiveSheet.Paste Range("B3").Select Windows("txfield.xls").Activate Range("D1").Select ActiveWindow.Close For r = 1 To 1000 A$ = Cells(r, 31) If Left(A$, 5) = "IMPAC" Then GoTo Skipout If A$ = "Approved:" Then Cells(r, 33) = "" Next r Skipout: Call Parse Call MoveDATA ActiveSheet.Unprotect ''Temporary Call Tidy_Up End Sub

33 Developing Strategy 2 - Step 2 Mechanism for transferring data from the electronic chart to the Excel spreadsheet Mechanism for transferring data from the electronic chart to the Excel spreadsheet

34 Creation of the C:\WINDOWS\Temp\txfield.xls file Click on Open Patient Chart in File Menu or Press F2 Patient Selection

35 Click on Open Patient Chart in File Menu or Press F2 And begin typing patient’s last name Aaaa, Aaaa

36 Patient Selection

37

38 When patient sought is highlighted in first row….

39 Patient Selection Double click highlighted row or Click on the Select button Click on Chart Navigator Icon Click on Physics Tab and Diagnosis & Interventions Tab

40 Export Data & View Available Fields Click on Print Reports in File Menu or Hit F3 Highlight Tx Fields in Report Navigator

41 Export Data Click on the Run Button or Double Click on Highlighted item.

42 Export Data Select Tagged & Click OK

43 Export Data Highlight Appropriate Fields & Click Select

44 Export Data Be Sure File is Selected

45 Export Data Be Sure File is Selected & Click OK

46 Export Data Highlight Excel8.0 (Extended) & Click OK

47 Export Data Choose Format Options as Shown & Click OK

48 Export Data to file in C:\WINDOWS\Temp Accept Default Filename “TxField” & Click on the Save button

49 Export Data Click Yes to Overwrite File Question

50 Export Data Screen Display During Data Export Process

51 Export Data Click Close Button

52 Export Data Click Close Button

53 Getting the MU Calculation Check Spreadsheet Click on Novell-… Button in Task Bar

54 Getting the MU Calculation Check Spreadsheet Click on My Shortcuts

55 Getting the MU Calculation Check Spreadsheet Click on Shortcut to Adac_IMPAC…xls

56 Getting the MU Calculation Check Spreadsheet Click on Import Data Button

57 Importing Data into the MU Calculation Check Spreadsheet Click No

58 Importing Data into the MU Calculation Check Spreadsheet Name

59 Entering Data in the MU Calculation Check Spreadsheet Name

60 Entering Data in the MU Calculation Check Spreadsheet Name

61 Entering Data in the MU Calculation Check Spreadsheet Name

62 Entering Data in the MU Calculation Check Spreadsheet Name After all data has been entered, click on Export Data button.

63 Data Copied by Value to Newly Opened Spreadsheet, Blank_002.xls, …. Name Click on the SAVE button to save a copy of Blank_002.xls as Name-Course-RxSite-TxArea.xls

64 …and SL15_AllX_Adac_IMPAC_002.xls Is closed. Name Click No

65 Print sheet to… Name

66 ….printer (for paper chart for now)…. Name

67 ….and prepare to print to file. Name Click on cell with Filename in it, Highlight text in formula window, Hit Control-C to copy text,

68 ….and prepare to print to file. Name Click on an empty cell, and click on the Print to File button

69 ….and prepare to print to file. Highlight Blank_002 in Filename text box and type Control-v to paste in new filename

70 To save file in PDF format… Name …click the Save button

71 Exit EXCEL Name

72 And Do Not Save Changes to Blank_002.xls Name Click No

73 Back to Where We Started

74 How Does It Work? 1.Export data from IMPAC by creating txfield.xls = TXF) 2.Know structure of TXF 3.Open MU Calc Spreadsheet (MUC = SL15_AllX_Adac_IMPAC_002.xls) 4.Use MACROs in MUC initiated by the IMPORT button A.to open TXF B.copy contents of TXF to clean section (CS) of sheet 1 of MUC C.decipher (parse) and move data from CS to cells of calculational part (CP) of spread sheet using VBA code in MUC. D.Enter additional data not contained in IMPAC in CP. E.Tweak wedge angle if necessary. F.After reconciliation between ADAC and CP…. 5.In MUC click on the EXPORT button which A.Opens spreadsheet Blank002.xls = BLN B.Copies contents of MUC to BLN (by value i.e. does not copy formulas)

75 6.Use the SAVE button in BLN which A.Closes MUC B.Saves a copy of BLN as Name-Course-RxSite-TxArea.xls 7.Print to 1.Hardcopy printer 2.File in PDF format to be imported in IMPAC as part of the electronic record 8.Close Excel without saving changes to Blank_002.xls

76 Txfield.xls produced by IMPAC Field 2’

77 Txfield.xls produced by IMPAC Field 2’ End of Record

78 File Sizes Diode_Version.xls~ 40K SL15_AllX_Adac_IMPAC_002.xls~280K Stored_Version_of_Above.xls~ 70K Stored_Version_of_Above.pdf~ 9K

79 Recovering “Damaged” Files

80 Code Visual Basic (VB) The Basic part of VB is “Basic” as taught in high school. The “Visual” part of VB can learned by knowing the function of objects in the forms tool box. Code can be generated by recording Macros.

81 Best Wedge Algorithm Name The wedge angle is varied until the agreement between ADAC and EXCEL for the wedged and open components are about equal. The variation between ADAC and EXCEL increases as the off- axis increases. Typically  angle < 5 o. Interestingly, as the wedge angle is varied, the overall agreement does not change significantly.

82 The End


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