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How to Make the Final MU Check Occur After the Last Human Intervention in an Electronic Chart

How to Make the Final MU Check Occur After the Last Human Intervention in an Electronic Chart. Alan Kepka Northwestern Memorial Hospital. Data Transfer by Dosimetry / Physics.

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How to Make the Final MU Check Occur After the Last Human Intervention in an Electronic Chart

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

  2. Data Transfer by Dosimetry / Physics 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

  3. 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 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)

  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. Tx Planning System RV System Stores Tx Script & Records Tx Linear Accelerator For Current Technology (circa. 2006) the Following Processes Occur. The Tx planning computer downloads data to the RVSystem 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 MLCshapes 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. 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 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

  7. A Complication Introduced by DICOM RT DICOM RT does not consider bolus as a RT structure

  8. 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 For Paperless Tx Scripts

  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(60o) 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. If Wedge angle = 60o, 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 . Wedge ~20o NOT GOOD!! Representation 3 used by ADAC, IMPAC and Elekta

  13. Strategy 1. For wedged fields, have 2nd. 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. To Catch MU Vector Entry Errors

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

  17. Acceptable Agreement 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 +/- 10% window for diode readings Example of Diode Readings

  18. Rational for Developing Strategy 2

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

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

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

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

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

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

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

  27. 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(SSDoffaxis, Depthoffaxis, OADdepth) Off-Axis Wedge Transmission Factor id, tray = identification of tray s = equivalent square field OADdepth = Off-Axis distance at Depth nX = beam energy id number Typical Functions Affected

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

  29. 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 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

  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) = 1.027 End Sub Beam Energy Index 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

  31. Click on Import Data Button 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 . . . . .

  32. 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 How to Retrieve Data from Electronic Record

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

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

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

  36. Patient Selection

  37. Patient Selection

  38. Patient Selection When patient sought is highlighted in first row….

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

  40. Click on Print Reports in File Menu or Hit F3 & View Available Fields Export Data 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

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