PCXMC 2.0
Contents
1. with changes of patient age patient File About STUK TR 7 size or examination geometry from the previously calculated cases involves three steps which will be explained in detail below In summary these steps require 1 defining the examination Monte Carlo simulation and 3 calculating the organ doses conditions 2 performing the for a specified x ray spectrum and patient input dose More simply referring to Figure 1 the subprograms behind the three buttons on the top row are executed successively from left to right If the risk is assessed from the calculated doses the risk assessment button is clicked after the three steps above ll x Figure 1 The main form of PCXMC Calculation of doses for a new case requires performing the three steps in the upper row of buttons from left to right STUK TR 7 If the patient data age weight height and the geometric data of the examination are unchanged from a previous calculation one does not need to perform the first two of the above steps and the patient dose calculation is accomplished by performing the step 3 only That is the user does not need to perform the Monte Carlo simulation again if just the x ray spectrum or the amount of radiation have changed of different extensions The program adds these extensions files Therefore do not use any extensions for the file The program produces files automatically and keeps track of the names t2. Projection angle and Cranio caudal angle specify the direction of the x ray beam with respect to the phantom The first of these angles specifies whether the x ray beam enters the patient from the front or back side or at any other angle i e it describes rotations in the xy plane and the latter angle specifies the tilting of the beam with respect to the xy plane All angles are given in degrees It is suggested that the user checks his her proper entering of these angles from the phantom image The check box Draw x ray field is used to control whether the x ray beam edges are shown in the phantom image It is useful to keep this box checked one might wish to leave the image without beam indication only in special occasions This selection has no effect on the calculation results The next row of data is for simulation details the maximum photon energy of interest and the number of photons in the simulation The maximum energy that will be used in the Monte Carlo simulation is typed in the field Max energy Maximum energy equal to 90 corresponds to a maximum allowable x ray tube potential of 90 kV in subsequent dose calculations Unless calculation speed is of great concern we suggest that this value is kept at its maximum Max energy 150 in order not to limit the allowable x ray tube voltages Number of photons is a main factor in determining the statistical precision that will be achieved in the Monte Carlo simulation
3. Clicking the Update Field button causes the formerly specified beam edges to be colored gray and the newly specified beam edges to be shown with the colors explained above The Stop button can be used for stopping the drawing procedure After drawing the phantom image the program draws also a simulated radiograph which shows the organs in the defined x ray beam as viewed from the x ray tube focal spot this picture mimics the x ray image of the specified examination conditions Those parts in the radiograph that are outside the phantom or x ray field are displayed black parts that belong to the phantom but not to any of the checked organs in the organ list are displayed grey Other colours correspond to the first organ in the path of a photon and are equal to the colours of the organ names in the list The user can check and uncheck organs to be displayed The user can choose whether the displayed radiograph is drawn with higher detail or more quickly by choosing the Quick or Sharp radio button The input data and the calculation results are not changed by these choices they affect only the radiograph image display on this form The x ray beam location can be edited similarly as in the phantom image by clicking on the image in an area depicting a specified organ color other than black or grey The clicked cursor position will then be the new x ray field centre 3 1 1 Examination data input form Field size calculator Th
4. extensions automatically Therefore do not use any extensions for the file names that you specify when saving a file in PCXMC Files containing the examination and patient parameters of Monte Carlo simulation use the extension df2 data files produced by the Monte Carlo calculation use the extension en2 and final dose calculation results for a specific x ray spectrum and input dose use the extension mG2 Risk assessment reports use the extension txt The energy files Leni show the examination data and a table of the mean absorbed energy per photon in keV photon for the simulated photon energies and organs of interest It also shows the statistical error estimated for these absorbed energies one standard deviation in percent A new x ray spectrum is calculated each time the user changes it and this spectrum is stored in the directory PCXMC MCINDATA SPECTRA as an ASCII file SPECTRUM TXT Fourteen first lines are used for various parameters like x ray tube potential anode angle and filtration After these lines the relative photon fluence spectrum is given in 1 keV bins the first bin spanning the energy range 0 5 1 5 keV The same spectral data are used for all dose calculations until the user specifies a new spectrum When first used for a given phantom age PCXMC generates data files in the directory PCXMC MCINDATA GRIDS These files consist of file pairs Gpar2XY asc and Grid2XY bin where XY denotes the age
5. STUK TR 7 harm from the radiation exposure of the gonads For such effects see ICRP Publication 103 NOTE Many mathematical models have been developed for estimating the cancer risk resulting from an exposure to ionising radiation PCXMC uses the model developed by the BEIR VII committee Committee on the Biological Effects of Ionizing Radiations BEIR 2006 Many factors e g limitations in the epidemiologic data contribute to the uncertainty of the risk estimation The BEIR VII committee suggests that the risk estimates should be regarded with a healthy scepticism placing more emphasis on the magnitude of the risk The committee estimates that the excess cancer mortality to solid cancers due to radiation can be estimated within a factor of two at 95 confidence level For leukaemia the corresponding factor is four For individual solid cancer sites the risk estimation may have large uncertainties up to an order of magnitude or more BEIR 2006 In order to assess the risk of radiation induced cancer death for a given patient the user needs to enter correct patient data for the Age Gender and mortality Statistics Euro American Asian or Finnish of the patient The risk assessment is based on the equivalent doses shown in the fields on the left side of the form One may enter the values manually or get them from previously calculated dose files mG2 see section 3 3 Some mortality statistics data do not
6. can then return to the main form by clicking the Main menu button The results of the simulation are automatically stored under the same name as the definition file of the simulation conditions but the extension df2 is replaced by en2 This file is then used for calculating the organ doses for any x ray spectrum or input dose that the user is interested in without the need to make new simulations as long as all other examination parameters are kept unchanged Note that when the program is used for the first time for calculating doses in a phantom of a specified age it automatically creates additional data in the directory PCXMC MCINDATA GRIDS and may prompt the user to wait for the completion of this operation This operation is not done in later simulations 3 3 MAIN MENU BUTTON Compute doses Clicking this button on the main menu Figure 1 opens a form see Figure 4 for calculating the patient s organ doses in an x ray examination It is required that the Monte Carlo simulation part section 3 2 for the examination conditions in question has been performed earlier The data for the presently loaded x ray energy spectrum specified by the x ray tube voltage kV anode angle and total filtration are shown on the form If these data correspond to the spectrum that the user wishes to use the user can proceed directly to the dose calculation If the spectrum needs to be changed click the Change X ray Spectrum bu
7. the program 4 References BEIR Committee to Assess Health Risks Exposure to Low Levels of Ionizing Radiation BEIR VII Washington D C National Academy of Sciences 2006 from Cristy M Mathematical phantoms representing children of various ages for use in estimates of internal dose NUREG CR 1159 ORNL NUREG TM 367 Oak Ridge Oak Ridge National Labora tory 1980 Cristy M Eckerman KF Specific absorbed fractions of energy at various ages from internal photon sources I Methods Report ORNL TM 8381 V1 Oak Ridge Oak Ridge National Laboratory 1987 ICRP International Commission on Radiological the International Commission on Radiological Protection ICRP Publication 60 Annals of the ICRP 1991 21 1 3 Protection 1990 Recommendations of STUK TR 7 ICRP International Commission on Radiological Protection The 2007 Recommendations of the International Commission on Radiological Protection ICRP Publication 103 Annals of the ICRP 2007 37 2 4 ICRU International Commission on Radiation Units and Measurements Patient dosimetry for x rays used in medical imaging ICRU Report 74 Journal of the ICRU 2005 5 2 Tapiovaara M Siiskonen T PCXMC A Monte Carlo program for calculating patient doses in medical x ray examinations 2nd Ed STUK A 231 Helsinki Sateilyturvakeskus 2008 STUK TR 7 APPENDIX 1 The program produces files of different extensions during the operation The program adds these
8. uninstall it according to your preference The new version can be installed in the same folder as the previous version the different versions do not cause any problems to each other If you wish to remove the old version you should do it before installing the new version Otherwise if you uninstall the old version later some files that are common to both versions will be deleted and the program does not work properly To install the program in your PC from the PCXMC 2 0 Installation Disk follow the instructions below e Put the PCXMC 2 0 Installation Disk in the CD ROM drive e Run the PCXMC20_Setup exe program on the installation disk this is the installation program of PCXMC and it will guide you through the rest of the installation procedure The installation program will suggest C Program Files PCXMC as the folder where the program and data will be put If you wish you can install the program also elsewhere e During installation a short cut to the program is added to your desktop The default working directory of the program is PCXMC MCRUNS which is created during installation this directory is suggested for keeping the data that you ll generate when using the program It may happen that this default directory is not set properly when you first run the program In this case you can restore this default working directory by choosing Restore default directory in the File menu in the Examination data form which is d
9. 17t row 18 row 19t row 20 row 21st row 22n row 23 4 row X ray beam height at the distance FSD from the x ray tube focal spot real in centimetres the value must be greater than 0 The x coordinate of the reference point inside the phantom real in centimetres The y coordinate of the reference point inside the phantom real in centimetres The z coordinate of the reference point inside the phantom real in centimetres The maximum energy to be used in the simulation integer range 1 15 this number times 10 is the maximum x ray tube voltage in kV that can be used The required value can be calculated from the x ray tube voltage of interest U by U 0 5 kV 10 1 kV and truncating the result to an integer A higher value can be defined as well but results to an unnecessary long computation time The number of photon histories per energy to be used in the simulation integer multiple of 100 This number affects the speed of the calculation and the accuracy of the results It can be e g equal to 1000 if there is no need for a good statistical accuracy but usually higher values are recommended The x ray tube high voltage integer in kilovolts less than or equal to 150 See also the requirement on the 14 data row above The x ray tube target angle real in degrees typical values of diagnostic x ray tubes are of the order of 12 18 The atomic number of the first filter material Z i
10. D If the equivalent doses have been obtained from dose files mG2 calculated with PCXMC the user need not worry about the proper value of the weighted remainder dose the program takes care of it directly If doses are edited manually the responsibility of entering a proper value for the Weighted remainder dose is left to the user As already suggested above equivalent organ dose values can be fed either manually or by letting the program sum the organ doses from the selected dose files The latter method is evoked by clicking the Open dose data and clear old doses button The gonads are an exception here they have been assigned only half of their tissue weighting factor value because PCXMC does not consider genetic harm 16 entered the form shows data for a 30 year old Euro This choice initially sets all organ doses to 0 0 and then sums the organ doses in the files selected in the form that appears One can select multiple files at the same time by keeping the lt Ctrl gt key pressed during the selection or by keeping the lt Shift gt key pressed while selecting the last from a range of files When the Open button on the file selection form is clicked the program will calculate the sum of the organ doses and the weighted remainder dose and display them in the organ dose fields Further dose files can be added to dose files opened earlier without resetting the doses to 0 0 by clicking th
11. F equal to 1 5 is considered inappropriate the solid cancer risks should be multiplied by 1 5 The dose level of the notification can be changed by editing the corresponding datum in the file WarningDoses dat which is located in the folder PCXMC MCINDATA RISKDATA In order to warn for exceptionally large doses the program also notifies the user if such doses are found If the sum of incident air kermas from the dose files is larger than 1 Gy the user is noted on this and he she may wish to check whether the various x ray fields in these irradiations overlap to such a degree that deterministic skin effects are possible Note that if the sum of the incident doses is not above 1 Gy not even small parts of any organs will have local doses much in excess of 1 Gy regardless of the overlapping of the various fields The program also checks if the average absorbed dose in any of the organs considered in PCXMC is larger than 1 Gy and notifies the user by giving one example of such an organ all such doses can be viewed by printing or saving the risk report see below A further check is made of the average doses in various bones or bone groups considered in PCXMC If the average dose in any of them exceeds 3 Gy the program notifies the user on this The program also notifies the user if the dose in the uterus of a woman in child bearing age exceeds 100 mGy In spite of these notifications the user of the program should make the evaluation of
12. MC MCRUNS an example of a definition file of this kind is described below When PCXMC is started the program checks whether a file of this name exists in this folder If not the program will start and function like described in the main text of this User s Manual If the file exists the program will start the Monte Carlo simulation specified in the Autocalc df2 file and then calculate the patient s organ doses During the simulation the Simulation form is displayed showing the progress of the simulation and after finishing the calculation the program will exit During the execution of the program the Autocalc df2 file is renamed as XXX df2 where XXX denotes the string supplied in the last data row of the Autocalc df2 file see the example file below where the datum is PATIENT_ID The results of the intermediate Monte Carlo simulation are saved in file XXX en2 and the final patient STUK TR 7 USING THE AUTOMATIC FEATURES OF THE PCXMIC 2 0 doses are saved in the text file XXX mG2 So after the calculation there are three XXX named files and the Autocalc df2 file is deleted Before starting to process the Autocalc df2 file the program checks whether any of the three XXX files exists If any of them does exist i e the calculation has already been done for a similar name the program displays a warning and exits when the OK button of the warning is clicked The execution of the program stops also if there are er
13. STUK TR 7 NOVEMBER 2008 TR PCXMC 2 0 User s Guide Markku Tapiovaara Teemu Siiskonen Sateilyturvakeskus Stralsakerhetscentralen Radiation and Nuclear Safety Authority A STUK STUK TR 7 NOVEMBER 2008 PCXMC 2 0 User s Guide Markku Tapiovaara Teemu Siiskonen STUK eSATEILYTURVAKESKUS Osoite Address e Laippatie 4 00880 Helsinki STR LS KERHETSCENTRALEN Postiosoite Postal address e PL PO Box 14 FIN 00881 Helsinki FINLAND RADIATION AND NUCLEAR SAFETY AUTHORITY Puh Tel 09 759 881 358 9 759 881 e Fax 09 759 88 500 358 9 759 88 500 e www stuk fi ISBN 978 952 478 392 7 print ISBN 978 952 478 393 4 pdf ISSN 1796 7171 STUK TR 7 TAPIOVAARA Markku SIISKONEN Teemu PCXMC 2 0 User s Guide STUK TR 7 Helsinki 2008 19 pp apps 5 pp Key words PCXMC x ray diagnostics patient dose effective dose organ dose Monte Carlo method risk assessment computer program Abstract PCXMC is a computer program for calculating patients organ doses and the effective dose in medical x ray examinations It allows a free adjustment of the x ray projection and other examination conditions of projection radiography and fluoroscopy The anatomical data are based on the mathematical hermaphrodite phantom models of Cristy and Eckerman 1987 with some modifications and user adjustable phantom sizes The program also calculates the risk of death for radiation induced cancers This User s Manual explains ho
14. adiation risks Risk of exposure induced cancer death REID 0 000446 Cancer mortality for other causes not related to this exposure 20 1 Active bone marrow mSv 0 1068 Expected length of remaining life 28 2 years Breasts women mSv a Loss of life expectancy LLE 0 7 hours LLE REID 17 1 years Colon mSv 0 008086 Liver mSv 0 06977 Lungs mSv 0 2945 Ovaries women mSv 0 Prostate men mSv 8 4E 5 ZE mSv 0 2233 Cancer type REID Thyroid mSv 0 08385 Risk of exposure induced death REID for various cancers leukemia 5 31E 5 colon cancer 2 79E 6 Uterus cron IST liver cancer 9 91E 6 Urinary bladder mSv 0 000563 lung cancer 0 000239 Weighted remainder mSv 0 1045 prostate cancer 5 7E 9 Dose files summed Sample chestPA mG2 Sample chestLAT mG2 leukemia colon cancer q 4 stomach cancer 4 86E 5 thyroid cancer 1 73E 6 bladder cancer 9 93E 8 other cancer 9 05E 5 liver cancer lung cancer prostate cancer 4 s 4 stomach cancer thyroid cancer 1 bladder cancer 4 4 4 other cancer Figure 7 The risk assessment form of PCXMC When first American male with no radiation exposure from ICRP Publication 103 In this weighting the sum of the weighting factors of these organs is renormalised to unity for a unifrom dose D in all organs the weighted remainder dose would also be equal to
15. case that the radiation induced cancer is realised LLE REID The window also shows a bar chart of the probability the site specific REID value of various radiation induced cancer types This bar chart can be copied to Windows Clipboard by double clicking on it The natural i e not related to the exposure in question cancer mortality for the selected gender and statistics is also shown below the risk estimates It is noted that the cancer and mortality data used in PCXMC are mostly given in five year intervals However constant values are used for all ages above 90 years Therefore taking into account the fact that mortality increases with age and the latency period of radiation induced cancers the risk assessment results of persons above around 80 years of age are numerically higher than would be obtained if actual age dependent mortality data were available for the highest age group If needed the user may edit the data files that depict mortality and cancer incidence statistics for example to improve the data for the highest age groups or to use the statistics of his her own STUK TR 7 country for details see appendix 1 The solid cancer risk models use the dose and dose rate effectiveness factor DDREF of 1 5 BEIR 2006 If equivalent tissue doses above 50 mSv are involved in the risk assessment this value of the DDREF may be inappropriate and the program notifies this below the risk estimate If the use of DDRE
16. choice of the x ray examination technique The program also calculates an estimate of the patient s risk of death due to radiation induced cancer according to the sex and age dependent risk model of the BEIR VII committee BEIR 2006 For a more thorough explanation of the calculation details of the program see the folder PCXMC Manuals in your PC where a technical program document Tapiovaara and Siiskonen 2008 is saved during program installation This document can also be found in the web pages of the program http www stuk fi pexme This Users Manual concentrates only on the use of the program PCXMC 2 0 differs from the previous version 1 5 2 in a few respects e The error in the x ray spectrum calculation excess number of photons in the lowest energy bin when the x ray tube total filtration consisted only of heavy elements has been corrected e The phantom data have been updated from Cristy 1980 to those of Cristy and Eckerman 1987 with some additional modifications e The shape of the phantoms head and neck have been improved to better resemble the shape of humans e New organs and tissues extrathoracic airways lymph nodes oral mucosa prostate and salivary glands have been added STUK TR 7 e The calculation of the effective dose is now made according to both the previous ICRP 60 1991 tissue weighting factors and the present ICRP 103 2007 tissue weighting factors e A new feature in the program i
17. contain specified cancer statistics for all of the listed organs Such organs are marked with on the form doses for these organs are then not directly used in the risk assessment Instead the risk assessment of such organs and other organs not shown in the list is made using the Weighted remainder dose This dose represents the weighted equivalent dose of such other organs with the tissue weighting factors The Asian and Euro American mortality data are from ICRP Publication 103 and do not necessarily correspond to the average mortality statistics of all countries in these regions or the specific mortalitity statistics of individual countries in these regions The equivalent dose of an organ in mSv is numerically equal to the mean absorbed dose in that organ in mGy for photon or electron irradiation For other radiations such as e g neutrons the radiation weighting factor deviates from unity and must be taken into account when inputting the organ equivalent doses 15 STUK TR 7 ij pcxmc Risk assessment File Run About TL Main menu r Statistics Age Gender lol x Add further dose data Calculate risks Clear doses Print report Save report as E Input data 47 0 CiMale Euro American Finnish mortality data C Female FREE 47 0 year old male S Sum of incident air kermas in the selected dose files 0 58 mGy Finnish Sum of effective doses in the selected dose files 0 1408 mSv Stochastic r
18. e Add further dose data button and selecting one or more files similarly as above A list of all dose files that are summed is shown in the lower left corner of the risk form Previous manual editing of the doses is discarded when doses are retrieved by using either of these dose data retrieval buttons Manual editing has an effect only if it is done as the last step before assessing the risk If some of the doses are exceptionally high above 10 Sv the corresponding fields will be coloured yellow and if the dose is too high for a successful calculation the colour of the field is red These colour indications should not be directly interpreted as showing the usability of the risk model They are displayed for technical purposes only When all input data age gender statistics and equivalent organ doses have been specified the user will get the risk assessment by clicking the Calculate risks button A yellow warning label Risk data have not been updated Click Calculate risks on the form indicates that input data have been edited and do not anymore match with the risk data displayed on the form The data are updated and this warning label disappears when the user clicks the Calculate risks button or that label The risk estimate shows the exposed person s risk of exposure induced cancer death REID the expected length of his her remaining life the mean loss of life LLE and the mean loss of life in
19. e field size calculator calculates the FSD and the width and height of the x ray beam at the patient s STUK TR 7 entrance To use the calculator one must know and enter the x ray beam size at the image receptor plane i e the width and height of the actual x ray image the distance between the x ray tube focal spot and the image receptor FID and the distance between the patient s exit surface and the image receptor which can be typically of the order of 10 cm in Bucky tables The thickness of the patient is calculated by the program when the user clicks the Calculate button The patient thickness thus obtained corresponds to the phantom x ray beam location and direction data specified in their appropriate input fields on the examination data input form The calculated FSD and beam size data are copied to their input fields when the user clicks the Use this data button Unless this button is pressed the data entered in the field size calculator do not influence the input data or calculation results 3 2 MAIN MENU BUTTON Simulate Clicking this button on the main menu Figure 1 opens a new form to initiate the actual Monte Carlo simulation see Figure 3 Clicking the Open data for Monte Carlo simulation button opens a form that allows the user to choose a definition file for the simulation Several files can be chosen at the same time by keeping the lt Ctrl gt button pressed while clicking the names of definition file
20. ent_ID en2 and Patient_ID mG2 The last of these files contains the calculated dose data 24
21. erage dose in total body 0 035716 Skeleton 0 074937 Effective dose ICRP60 mSv 0 042921 Skull 0 004391 d Effective dose ICRP103 mSv 0 045029 Upper Spine 0 044352 Middle Spine 0 326392 Lower Spine 0 075329 L Abs energy fraction 58 042776 Figure 4 The dose calculation form of PCXMC The table is empty before a file has been opened Calculation of x ray spectrum E X ray tube potential Filter 1 Material Filter 2 Material 120 ky 13 Atomic Number 29 Atomic Number X ray tube Anode Angle Ia Chemical Symbol Cu Chemical Symbol OR Filter 2 Thickness 300 0 10 SC 0 8106 g cm 2 0 0894 aen Exit Generate this spectrum Exit Keep old spectrum Figure 5 The x ray spectrum calculation form of PCXMC 13 STUK TR 7 In PCXMC x ray tube filtration is specified by two different filters of arbitrary elemental materials These elements are chosen by entering their atomic number or chemical symbol in their proper fields Note that when entering either of these data the other is updated simultaneously If the chemical symbol is used the program requires that it is typed with the proper upper and lower case lettering e g Cu for copper If only one filter material is used the atomic number of filter 2 should be set equal to 0 or the chemical symbol of it should be cleared The filter thickness must be input in units of mm The program automatically calculates the mass thickness of the filter
22. escribed in section 3 1 For best graphics quality set the display mode of your PC to use at least 16 bit colour depth 65536 colours in the 8 bit display mode the graphics in the program will be of poor quality due to the small number of available colors The desktop size should be at least 1024 x 768 If the desktop size is too small horizontal and vertical scroll bars are created However the images on the examination data input form will not be shown properly and using the program becomes cumbersome Use normal or small fonts in the desktop settings of your PC large fonts may cause improper visibility of some forms of the program in some operating systems The installation program puts a copy of this User s Manual the Terms and Conditions of Use and the technical program document in the directory PCXMC Manuals A Using the program To start PCXMC 2 0 double click its icon on the desktop or choose PCXMC20 from the Programs folder after pressing the Start button on your task bar This will open the main menu of the program Figure 1 The main menu displays six buttons Examination data Simulate Compute doses Risk assessment About and Exit Clicking these buttons with the left button of the mouse or pressing the lt Alt gt key and the underlined letter executes different parts of PCXMC The function of these parts is explained in the following chapters The dose calculation for a new examination condition
23. g to use these files The use of Autocale df2 is explained in Appendix 2 The user can print the data by clicking the Print as text button The user can return to the main form by clicking the Moin menu button or by using the File menu Clicking the currently specified phantom and examination Draw button displays the geometry see Figure 2 If the examination data have been modified without clicking this button there will appear a yellow warning text on the form noting that the images do not correspond to the data on the form This message text disappears when the Draw button is clicked The phantom image will also show the edges of the x ray beam if the box Draw x ray field is checked Those parts of the x ray field that hit the phantom are indicated in red colour and parts that do not intersect the phantom are shown as green The background colour of the image is the same as is set for the Active Title Bar in the Windows Control Panel colour settings You can move the cursor over the phantom image to see the coordinates of the cursor point on the phantom surface and you can rotate the phantom by any angle to see it from different directions editing of the Rotation increment is allowed This rotation of the image can be done D by pressing the or buttons The input data or the calculation results are not changed by the above operations they affect only the phantom image display on this form
24. hat you save in PCXMC Files containing the examination and patient parameters for Monte Carlo simulation definition files use the extension df2 data files produced by the Monte Carlo calculation energy files use the extension Leni and the final dose results for specific x ray spectra and input dose dose files use the extension mG2 The risk assessment reports use the extension txt Input files from the earlier versions of PCXMC used the extension def for definition files if the user opens such a file the program prompts for the need to check the appropriateness of the beam location and changes the extension The checked definition file should then be saved for subsequent use by clicking the Save Form or Save Form As button For a more detailed explanation of the file types see Appendix 1 of this manual We recommend that the above files definition files energy files and dose files are kept in the directory PCXMC MCRUNS or that the user creates new subdirectories in this directory for organising the data This working directory can be restored by choosing Restore default directory in the File menu of the Examination data form In this version PCXMC 2 0 there are a few readily calculated Monte Carlo data sets which are located in subfolders of MCRUNS The data have been organised by the age of the patient and are for typical common projections 3 1 MAIN MENU BUTTON Examination data Clicking thi
25. in units of g cm according to the filter material and thickness The user cannot edit this field but it can be used as guidance if filtration is specified in terms of the mass thickness The new spectrum will be calculated and used until the user specifies a new spectrum when the user clicks the Exit Generate this spectrum button The changes are discarded if the button Exit Keep old spectrum is clicked Clicking the Open MC data for dose calculation button prompts for the selection of a en2 file calculated earlier see section 3 2 Choose the file whose name corresponds to the examination conditions you wish to calculate results for and click the Open button A new form Figure 6 is fal Patient input dose Input dose value 1 0000 mGy Incident air kerma value used in calculations 1 0000 mGy displayed prompting you to specify the input dose This datum can be input in one of five different quantities i air kerma at the phantom entrance point in the centre of the x ray beam mGy free in air i e incident air kerma ii exposure at the phantom entrance point in the centre of the x ray beam mR free in air iii air kerma area product mGy cm2 iv exposure area product R cm2 or x ray tube current time product mA s this option cannot be used if the user has input the value 0 0 for the FSD The accuracy of specifying the input dose by the tube current time product mA s is abo
26. in Table I Table I Standard measures of the phantoms in PCXMC Age y Height cm Weight kg Newborn 50 9 3 4 1y 74 4 9 2 5y 109 1 19 0 10y 139 8 32 4 15y 168 1 56 3 Adult 178 6 73 2 The standard height and weight of the phantom of the chosen age are shown below the height and mass input fields STUK TR 7 fay DefForm C Program Files PCXMC MCRUNS 15 year old 1 5y Abdomen AP DF2 Eile JT Main menu DC New Form Open Form H Save Form H Save Form As Print As Text Header text fr ypical abdomen AP 15y Bac data Age Phantom height Phantom mass E 0 C1 C5 DEE Ce Adult 168 10 55 90 V Arms in phantom Standard 168 1 Standard 56 3 IV Draw x ray field Par Update Field Stop Geometry data for the x ray beam Beam width FSD Beam height 85 40 23 32 31 04 Projection angle 270 00 LATR 180 AP 270 LATL 0 PA 90 Xref Yref Zret 0 0000 0 0000 19 9900 Cranio caudal angle 0 00 pos Cranial X ray tube neg Caudal X ray tube MonteCarlo simulation parameters Rotation increment J 30 iew angle 330 Max energy ke Number of photons al A 150 50000 m Field size calculator Vv i IV Pancreas a FID Image width Image height 4 SE TER 110 fi 8 24 Calculate lV Testes IV Upper large intestine IV Spleen IV Lower large intestine Phantom exit image distance 5 0 KR Lungs IV Small intestine VV Ovaries bk Th
27. it represents the number of photon histories that will be generated For this parameter we recommend a minimum value of 10 000 The program adjusts the number to the multiples of 100 If Max energy is set to 150 keV and Number of photons is 20 000 the simulation requires typically about 30 seconds of computation time on a PC with a 1 8 GHz processor The calculation time can be shortened by specifying a lower value for Max energy which then restricts the use of the data for x ray tube voltages higher than this value in kilovolts or Number of photons which then results in larger stochastic uncertainties in the data Clicking the button New Form initialises the input form data to a default set Open Form shows all files with the extension df2 or def and allows the user to open any of them in order to modify or view the data After editing the data they can be saved by clicking the Save Form or Save Form As buttons Note that if the data have already been used in simulation which is indicated by the yellow backed text above the header text the definition file must be saved with a new file name to avoid discrepant data files from being created Do not explicitly type the extension the program will add it automatically In PCXMC 2 0 there is one reserved definition file name Autocalc df2 that the user should not use here this would result in cutting the necessary data from the file and result to I O errors when tryin
28. l region that was to be edited according to item 1 above Edit the first two lines of these files to refer to the name of your country and the statistics source you will use Do not change any of the filenames 3 Edit the mortality and incidence data files found in item 2 above to correspond to the data of your country All these data show the lower limit of the age band the upper limit of the age band and the mortality or incidence per year and 100 000 persons To verify your interpretation of the original data see the Euro American or Asian data given in tables A 4 10 A 4 17 of ICRP Publication 103 The data need be given for ages between 0 and 120 years of age The widths of the data bins can be changed They need not be similar to those in the original data files and they need not be similar in all data files depicting cancer incidence or mortality APPENDIX 2 The program version PCXMC 2 0 is able to calculate the patient s organ doses automatically without user interference This feature enables the user of the program to calculate patient doses for example by using a batch program which renames the data file and calls PCXMC once for each of the data files to be processed This requires that the operating system allows renaming and deleting files in the MCRUNS folder without having the user to interfere with such operations This automatic calculation is evoked by saving a file named Autocalc df2 in the folder PCX
29. nteger e g 13 denotes aluminum and 29 denotes copper The thickness of the above filter real in millimetres The atomic number of a second filter material Z integer e g 13 denotes aluminum and 29 denotes copper If no second material is used the value must be set as 0 The thickness of the above filter real in millimetres The input dose quantity option string allowed set EAK EE DAP EAP MAS The input quantity and unit corresponding to these choices is EAK Incident air kerma in mGy no backscatter EE Entrance exposure in mR no backscatter DAP The product of air kerma and area DAP or KAP in units of mGy cm 2 EAP The exposure area product in Remi MAS The current time product in mA s The numerical value of the above input quantity real 23 STUK TR 7 USING THE AUTOMATIC FEATURES OF THE PCXIMIC 2 0 APPENDIX 2 24th row The name that will be used in saving the calculated data string maximum 30 characters There must be no files of this name and extension df2 en2 or mG2 in the folder PCXMC MCRUNS otherwise the Autocalc df2 file will not be processed 25 row and further rows will be not read by the program During installation the above example file Autocalc example df2 has been set in the folder PCXMC MCRUNS The user can try this feature by first copying this file and renaming it as autocalc df2 When started PCXMC20 will output files with names Patient_ID df2 Pati
30. of the phantom These files are used in subsequent Monte Carlo simulations If any of these files becomes corrupted or is accidentally deleted you should delete both the corrupted file and its companion file the program will generate them again when needed All other physical data files and statistical data files are in sub folders of PCXMC MCINDATA The data files are in ASCII form The user of PCXMC may modify the files used 20 FILE TYPES OF PCKMC for cancer risk assessment to correspond to the data of his her own country One may also try to improve the data for the highest age bin In this case not all of the below steps need be taken However we strongly suggest that the user first makes a backup copy of the folder PCXMC MCINDATA RISKDATA before editing any of the data To modify the data 1 You can edit one of the names in the file PCXMC MCINDATA RISKDATA statlabels dat to correspond to your country do not change the order of the names they correspond to the order of the radio buttons in the Statistics selection on the risk assessment form When edited the name of your country will be shown on the risk assessment form instead of the name of the region that was edited The letter after the amp sign will be underlined in the form 2 Check the filenames that are written in the files PCXMC MCINDATA RISKDATA XXMen inp and PCXMC MCINDATA RISKDATA XXWomen inp where XX refers to the origina
31. rors in the Autocalc df2 file e g the number of energy steps has been selected to be smaller than required for the specified x ray tube voltage or if the reference point is not located within the phantom An attempt to run normal definition files in the Autocalc mode will result to I O errors because these files do not contain all the required data An example of the Autocalc df2 file is given below It is a text file consisting of 24 data rows Each row begins with a 33 character wide explaining text which is not used by PCXMC the user may modify the explaining text The actual data field consists of the following 30 characters locations 34 63 The header row row 1 and the output file name row row 24 are exceptions to this latter requirement these data fields are allowed to be longer than 30 characters PCXMC discards any spaces in front of the actual data but spaces behind a string datum are included in the datum Note that in writing the explaining text in front of the actual datum one tab character is counted as one character 21 STUK TR 7 USING THE AUTOMATIC FEATURES OF THE PCXIMIC 2 0 APPENDIX 2 Header Typical scoliosis PA 15y ProjAngle 90 0000 OblAngle 0 0000 Age 15 PatientHeight 0 0000 PatientMass 0 0000 Hands L Fsd 150 4000 BeamWidth 16 5000 BeamHeight 55 0000 Xref 0 0000 Yref 0 0000 Zref 35 0000 NELevels 10 NPhots 1000 X ray tube voltage kV 100 AnodeAngle 14 Fil
32. s or by keeping the lt Shift gt button pressed while selecting the last from a range of files The program will then simulate these conditions one after another automatically without user interference For example the program can be left simulating several conditions overnight When the OKT button is clicked the simulation starts and the fields on the form show the data and progress of the calculation the file name and header text of the definition file are shown the field Energy keV shows the photon energy under calculation Lot No shows the number 1 to 10 of the present batch and Photons in the lot shows the number of photons simulated at the present energy level in the present batch 11 STUK TR 7 PCXMC Simulation KE File Open data for Monte Carlo simulation Stop simulation jl Main menu File name C Program Files PCXMC MCRUNS 10 year old 1 O0y Chest AP_DF2 Header text Typical chest AP 10v Age f SkinPoint 00000 34000 355800 Focus 0 0000 136 6000 36 5800 Energy keY Lot No Photons in the lot Figure 3 The Monte Carlo simulation form of PCXMC The simulation can be stopped at any stage by clicking the Stop simulation button but then all simulation data of the present simulation run are lost if several simulations have been specified the completed simulations are saved The calculation is ready when a message box with text Done is displayed The user
33. s button opens a form see Figure 2 where the user defines the x ray examination conditions and the phantom model which will be used in the subsequent Monte Carlo simulation The data are saved as a definion file df2 when the editing is complete The title bar at the top of the form shows the file name and full path of the opened definition file If no file has been specified there is no text between the brackets On the first data row there is an input field displaying the header text This data field can be used for a short user typed text to further explain the simulation conditions If the Monte Carlo data have already been calculated for an opened definition file there will appear a text on yellow background above the header input field notifying this In this case the user must save the data using another definition file name after editing the data Renaming will be prompted when the user will try to save the changed definition file or exit the examination data input form The next row of data is for specifying patient data age height and mass The age is chosen by checking the proper radio button The age dependent standard height and weight of each phantom are obtained either by entering their proper values in cm and kg or the value 0 in the fields of these data Instead of the standard values actual patient measures can be used for height and weight data as well The standard measures of the phantoms are shown
34. s that it is now able to perform automated computation of doses without user interference during the calculation This feature is explained in Appendix 2 e Another new feature in the program is that it is now able to estimate the patient s risk of death by radiation induced cancer The input data files def of the earlier PCKMC versions are mostly compatible with version 2 0 however the z coordinates of the head and neck of the phantoms are now somewhat changed from the earlier phantom models and therefore the user needs to check the appropriateness of the beam location and beam edges in cases where these body parts are involved The program notifies the user on this if input data files of earlier PCXMC versions are opened The energy files Ge Monte Carlo simulation results ene or dose files mGy of the old versions cannot be opened with the new version the results need be resimulated if calculations with the new program version are needed PCXMC 2 0 runs under Microsoft Windows 32 bit operating systems Windows95 98 NT 2000 XP Vista A PC equipped with a processor of at least 120 MHz clock rate is needed for the use of the program but a more powerful PC is recommended for shorter calculation times The examination data input form needs a desktop area of at least 1024 x 768 to be fully visible STUK TR 7 2 Program installation on hard disk If you have an older version of PCXMC in your computer you can keep it or
35. ter A Z 13 Filter A mm 30 Filter B Z 29 Filter B mm 0 1 Input dose quantity EAK Input dose value 1 24 Output file name Patient_ID The data in the Autocalc df2 file are after the 33 character explaining text 1st row Text for the header text string commenting data 2nd row The projection angle of PCXMC real in degrees 3rd row The cranio caudal angle of PCXMC real in degrees 4th row The patient s age integer allowed set 0 1 5 10 15 30 30 denotes an adult patient 5th row The patient s height real in centimetres the value 0 0 corresponds to the standard value for the phantom of the given age 6th row The patient s weight real in kilograms the value 0 0 corresponds to the standard value for the phantom of the given age 7h row Arms included in the phantom integer allowed set 0 1 0 arms removed 1 arms included 8th row The x ray tube focal spot to skin distance FSD real in centimetres the value 0 0 implies an infinite distance the option of specifying the input dose in terms of the current time product mA s is not allowed if FSD 0 0 see the data for 22 gt 4 row 9th row X ray beam width at the distance FSD from the x ray tube focal spot real in centimetres the value must be greater than 0 22 APPENDIX 2 USING THE AUTOMATIC FEATURES OF THE PCXMIC 2 0 STUK TR 7 10 row 11 row 12 row 13 row 14 row 15 row 16 row
36. the possibility of deterministic effects and the need of any further actions by the basis of professional judgement and not rely on the calculated results only If the user wishes to use another set of warning levels he she can modify them by editing the file WarningDoses dat which is located in the folder PCXMC MCINDATA RISKDATA The buttons Print report and Save report as can be used for printing and saving the risk report respectively In addition to the data shown on the form also the summed doses of all dose files for all organs will be output 17 STUK TR 7 in the printed or saved report This may be useful also for easily calculating the doses from an examination which consists of several exposures The button Clear doses sets all organ doses to the value 0 0 Clicking the button Main menu brings the user to the main menu Figure 1 3 5 MAIN MENU BUTTON About The About form shows data about the PCXMC program e g the version number and the location of the manuals Clicking the address http www stuk fi pcexme on the form starts the default Internet browser of your computer and shows the www pages of PCXMC if you are connected to the Internet Known errors in the various PCXMC versions are shown in the page PCXMC version information You can send e mail to us by clicking on the link E mail to pexmc stuk fr 3 6 MAIN MENU BUTTON Exit Stops the execution of
37. tions may be low even for a large number of photon histories if the dose in the organ is low and or the organ is small It should also be noted that when the number of interactions is small which is indicated by a high value of the statistical uncertainty several tens of percents the estimate has a skewed non normal distribution and the actual statistical errors may be significantly larger than expected on the basis of the standard deviation However it should be understood that the statistical error is usually a small factor in the total uncertainty of the results The differences between the phantom and the actual patient and the differences between the simulated and true geometry will often dominate Save As saves the dose data in a file by the name that the user supplies these files are saved using the default extension mG2 Print is used for sending the dose data to a printer Again clicking Main menu takes the user back to the main menu If you wish to use the calculated dose data in risk assessment section 3 4 you must save the data here before performing the risk calculation 3 4 MAIN MENU BUTTON Risk assessment Clicking this button on the main menu Figure 1 opens a form see Figure 7 for assessing the risk of radiation induced cancer death PCXMC also notifies the user if high doses that may be capable of causing deterministic health effects are found PCXMC does not assess the genetic
38. tton and define the x ray tube voltage target angle and total filtration in the form that appears Figure 5 STUK TR 7 PCXMC Dose Calculation File Run i Main menu Change X ray Spectrum Open MC data for dose calculation Print H Save As X ray tube potential 120 kV Filtration 3 mm Al 0 1 mm Cu Anode angle 17 deg en mulation Obl an 160 000 cm g Scaling factors oe 120 kv Filter dth 2010 cm and heig Phantom height 3 600 cm and mass Incident air kerma 0 150 mGy Tube volte cm 0 000 0 000 52 000 y 000 andsz 1 000 3 mm Al 0 1 mm Cu A i Scapulae 0 400557 0 154045 Clavicles 0 060160 0 000822 Ribs 0 288670 0 035366 L Upper arm bones 0 035092 Colon Large intestine 0 003454 H Middle arm bones 0 039175 Upper large intestine 0 005363 Lower arm bones 0 006518 Lower large intestine 0 000929 H Pelvis 0 002112 Extrathoracic airways 0 007761 5 Upper leq bones 0 000026 Gall bladder 0 027439 A Middle leq bones 0 000001 Heart 0 058200 Lower leq bones 0 000000 Kidneys 0 092431 Skin 0 024164 Liver 0 065439 L Small intestine 0 004068 Lungs 0 131340 Spleen 0 124134 Lymph nodes 0 035024 Stomach 0 037965 Muscle 0 027625 L Testicles 0 000001 Oesophaqus 0 081588 Thymus 0 029615 Oral mucosa 0 002377 Thyroid 0 023657 Ovaries 0 000911 S Urinary bladder 0 000195 Pancreas 0 073502 k Uterus 0 000731 Prostate 0 000068 Salivary glands 0 004203 U Av
39. ut 30 given that the x ray tube voltage and tube current time product displays of the x ray system considered are correctly calibrated The program converts the input dose quantity to incident air kerma in milligrays When the OK button is clicked the calculated organ doses and other dose quantities are displayed in milligray or equivalently in millisievert along with their estimated statistical precision Statistical uncertainty is shown in percents and the symbol NA not applicable is used when the uncertainty estimate could not be done because the dose is zero or very close to it If the user is not satisfied with the statistical precision the Monte Carlo simulation should be redone with a larger number of photons larger value of Number of photons in the Examination data form Increasing O x Input dose quantity and unit Ze Incident air kerma mGy C Dose Area Product mGycm 2 C Entrance exposure mR C Exposure Area Product Rem 2 C Current Time Product m s Corresponds to about 93 7mAs Cancel Input dose quantities are for measurements without BSF Figure 6 The input dose specification form of PCXMC 14 the value of Number of Photons by a factor of four approximately halves the error It should be noted that the accuracy of both the dose estimate and its statistical error depend on the number of simulated interactions in the organ considered The number of interac
40. w to use the program version 2 0 The technical documentation of the program is published in report STUK A231 which describes the concepts methods and data used in PCXMC 2 0 STUK TR 7 Contents ABSTRACT 1 GENERAL 2 PROGRAM INSTALLATION ON HARD DISK 3 USING THE PROGRAM 3 1 MAIN MENU BUTTON Examination data 3 1 1 Examination data input form Field size calculator 3 2 MAIN MENU BUTTON Simulate 3 3 MAIN MENU BUTTON Compute doses 3 4 MAIN MENU BUTTON Risk assessment 3 5 MAIN MENU BUTTON About 3 6 MAIN MENU BUTTON Exit 4 REFERENCES APPENDIX 1 FILE TYPES OF PCXMC APPENDIX 2 USING THE AUTOMATIC FEATURES OF THE PCXMC 2 0 Note on the use of various fonts in this document Names of items buttons edit boxes etc on the forms are printed in italic font Text that we wish to highlight is printed in bold font Text depicting data in a text file is printed using Courier OND Ow 11 12 15 18 18 19 20 21 1 General PCXMC is a computer program for calculating patients organ doses and effective doses in medical x ray examinations radiography and fluoroscopy The organ doses are calculated in 29 organs and tissues The program calculates the effective dose with both the new tissue weighting factors of ICRP Publication 103 2007 and the old tissue weighting factors of ICRP Publication 60 1991 The program incorporates adjustable size paediatric and adult patient models and allows a free
41. yroid FSD Beam width Beam height E Kidneys Urinary bladder LJ Use this data V Thymus M Gall bladder IV Stomach M Oesophagus IV Salivary glands M Prostate F Iv Oral mucosa M Pharynx trachea sinus Ze Quick Sharp Figure 2 The x ray examination data input form of PCXMC A check mark in the check box Arms in phantom implies that the arms are included in the phantom during simulation Remove the arms from lateral projections where the arms are positioned outside the x ray beam in actual practice by unchecking the box The next rows are for geometric data for the x ray beam All length and position data are entered assuming cm as the unit of length FSD focus skin distance means the distance between the focal spot of the x ray tube and the skin entrance point of the central axis of the x ray beam If the value 0 is used for FSD the program will interpret the distance to be 10 000 cm and all photons are practically unidirectional this choice may be useful for example when point scanning x ray beams are used in the examination Beam width and Beam height refer to the lateral and vertical dimensions of the x ray beam as measured PCXMC does not consider the attenuation of radiation in air at the distance FSD from the focal spot and in the plane that is normal to the central axis of the x ray beam They do not refer to the x ray field size at the image receptor If only the latter data for beam si
42. ze is available one must first calculate the beam size at the skin entrance from the image size focus image distance FID and FSD These calculations can be easily done using the field size calculator at the lower left part of the examination data input form The use of this calculator is explained in detail in the section 3 1 1 Xref Yref and Zref are the coordinates of an arbitrary point inside the phantom through which the central axis of the x ray beam is directed these data are used for specifying the location of the x ray beam with respect to the phantom Choosing any point along the intended beam centre line will give same calculation results The origin of the phantom s coordinate system is located at the STUK TR 7 centre of the bottom of the phantom trunk section The positive z axis is directed upwards the positive y axis to the back of the phantom and the positive x axis to the left hand side of the phantom The graphics capabilities the phantom image and the radiograph can be used as a guidance in finding proper coordinates for the reference point The reference point can be most easily edited by clicking the mouse within either the phantom image or the radiograph In the former case the reference point will be put just below the phantom surface at the position of the cursor when the button is clicked and in the latter case the reference point is put below the surface of the organ clicked
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