HDR 1000 QA Tool
Contents
1. HDR 1000 QA Tool REF 70008 STANDARD IMAGING INC TEL 800 261 4446 7601 Murphy Drive TEL 608 831 0025 Middleton WI 53562 FAX 608 831 2202 May 2004 2004 Standard Imaging Inc www standardimaging com DOC 80012 04 I D pe General Precautions CAUTION Warnings and Cautions alert users to Proper use of this device de dangerous conditions that can occur if pends on careful reading of instructions in the manual are not obeyed Warnings are conditions that can cause injury to the operator while Cautions can cause damage to the equipment all instructions and labels T CAUTION This device should never be submerged to clean or scrubbed with an abrasive cleaner CAUTION Insure source freely moves within secured catheter Proper location of source is necessary to assure proper calibration Table of Contents PAGE 2 General Precautions Overview Wall Mount for QA Measurements Description Operation Procedure A Initial Procedure B Calibrations for Constant K C Standard QA Procedure Table 5 Documentation of Results Table 6 Table 7 Parts and Accessories List Maintenance Service Policy Customer Responsibility Warranty D 2 2 Joa amp Overview Standard Imaging 7601 MURPHY DRIVE MIDDLETON WI 53562 Accurate delivery of doses using an high dose rate HDR brachytherapy remote afterloading system depends on predicting the strength of the2. tool insert tightly collimates the radiation received by the chamber to a narrow plane When the source lies in that plane the chamber responds with a large signal when the source falls partially or completely out of the plane the signal greatly diminishes Lead Acrylic Ny y 4 mm ii 51 mm Figure 1 Schematic drawing of HDR QA Tool Operational Procedure This response curve is shown in Figure 2 For checking positional accuracy the high slope regions of Figure 2 designated point A are the most useful For checking dwell time and activity a plateau designated point B in Figure 2 rather than a peak is desired With this tool the source position verification timer accuracy and consistency of the source activity can be measured in a simpler manner by using the method described below Point B 0 8 lt Paint A 3 06 e 2 0 4 a r e wet TT 202 930 940 950 960 970 Reference Length mm Figure 2 Representative response curve using HDR QA Tool insert of Fig 1 The high slope region is designated A and the plateau region is designated B A Initial Procedure 1 Insert the HDR QA tool into the well of the HDR 1000 lon chamber 2 Insert the catheter from the HDR after loading machine through the opening in the top of the HDR QA tool Push the catheter to the bottom of the chamber and lock the catheter in place with the pr
3. alculations are given in Med Phys 22 435 440 1995 The following expression for a constant K can be determined from the measurements for each point taken above 1 K x t Q x t C A e0 t OR 2 K x I x C JA et Where K x t is the function that relates the response of the system to x and time t this function will be a constant for a given point of measurement Q x t is the charge measured when the source is in position x for time t where x is the position of the source in the QA insert and t is the exposure time if using a gated measurement system or otherwise the effective time adjusted for transit time effects I x is the current measured when the source is at position x Co is the correction for temperature and atmo spheric pressure for the ionization chamber A is the source strength at the time of calibration of the Ir 192 source 4 Correct the readings for temperature and pressure 5 Determine the values of the constant K See section B Calculations for constant K below for points A and B corrected to a standard temperature and pressure When the HDR QA tool is first used a determination of the value of K for each of points Aand B as measured above must be made thereafter it will be a constant for your HDR unit Thus thereafter only measurements of points A and B need to be made t is the time since the calibration is the decay constant of Ir 192 When an analysis is
4. ard Imaging Electrometers 2 years Standard Imaging Software Products 1 year All Other Standard Imaging Products 1 year Standard Imaging Custom Product 90 days Consumables 90 days Serviced Product 90 days Resale Products As defined by the Original Equipment Manufacturer 0 90 days 100 of ADCL Calibration Costs ADCL Product Calibration 91 182 days 75 of ADCL Calibration Costs Standard Imaging uses the UW ADCL for 183 365 days 50 of ADCL Calibration Costs recalibrations required under warranty 366 639 days 25 of ADCL Calibration Costs days from date of shipment to customer Standard Imaging s sole and exclusive obligation and the purchaser s sole and exclusive remedy under the above warranties are at Standard Imaging s option limited to repairing replacing free of charge or revising labeling and manual content on a product 1 which con tains a defect covered by the above warranties 2 which are reported to Standard Imaging Inc not later than seven 7 days after the expiration date of the warranty period in the table 3 which are returned to Standard Imaging Inc promptly after discovery of the defect and 4 which are found to be defective upon examination by Standard Imaging Inc Transportation related charges including but not limited to shipping customs tariffs taxes and brokerage fees to Standard Imaging are the buyer s responsibility This warranty extends to every part of the p
5. ction Manual O Ring QA Tool Torque Wrench QA Tool Catheter Fixator QA Tool Maintenance If assistance is desired in the proper disposal of this product including accessories and components after its useful life please return to Standard Imaging There are no servicable parts on the QA Tool Insert Notes 10 Service Policy If service including recalibration is required please contact Standard Imaging s Customer Service department by phone or email prior to shipping the product Standard Imaging s Customer Service and Technical Service staff will attempt to address the product is sue via phone or email If unable to address the issue a return material authorization RMA number will be issued With the RMA number the product can be returned to Standard Imaging It is the responsibility of the customer to properly package insure and ship the product with the RMA number clearly identified on the outside of the pack age The customer must immediately file a claim with their carrier for any shipping damage or lost shipments Return shipping and insurance is to be pre paid or billed to the customer and the customer may request a specific shipper Items found to be out of warranty are subject to a minimum service fee of 1 hour labor excluding recalibrations for diagnostic efforts and require a purchase order PO before service is performed With concurrence from customer the product may be replaced if it
6. d QA Procedure 1 Set up catheter and QA Tool as described in steps A1 through A2 2 Set the HDR unit to move the source to the selected points A and B from above Take current measurements at these points Then take a charge measurement each for times t and t e g 10 seconds and 5 seconds at point B Record data and calculations on a chart as shown in Table 6 Documentation of Results 3 Correct to a standard temperature and pressure 4 Determine the day s values of the con stant K at points A and B 5 Compare the day s value for K to the ini tial value Determine a percent difference for the present value of K versus this initial or average value for each measurement at points A and B Sample QA charts are given in Tables 6 and 7 to retain a record of the QA measurements In lieu of using these charts columns can be added to the facility s regular QA form Table 6 QA Chart for HDR Source Date Initials Point A current nAICi Table 7 QA Chart for HDR Source Date Initials Point A current nAICi Point B current nAICi Point B current nAICi HDR UNIT DISTANCE INDICATION Point B integrated KB QB t1 QB t2 nC Ci nC nC HDR UNIT DISTANCE INDICATION Point B integrated KB QB t1 nC s Ci nC Parts and Accessories List REF 70008 70007 80012 10040 10041 30053 Description HDR QA Tool Wall Mount Bracket HDR QA Tool Instru
7. done for the uncer tainties associated with the parameters of measurement the total contribution is equivalent to 0 7 See Table 1 for uncer tainties for individual measurements There fore any changes in the value of K greater than 1 5 may be considered significant Therefore a 1 mm error in position would become approximately a 20 change in the current based K or greater than 10 times the measurement uncertainty The standard deviation of a number of trials without any changes has been shown to be within 1 Table 1 Showing uncertainty in test of K Test Uncertainty in Test Source Position Dwell Time Source Activity Consistency Operational Procedure Table 2 lists the ranges of error for position ing based on the difference in the value of K If the determinations of AK remain less than 10 the error in positioning is lt 0 5 mm Table 3 has listed ranges of error based on the difference in the value of K from the av erage value of K The values given in Table 3 are based on two standard deviation limits and the uncertainty analysis given above For example if all of the determinations of AK remain within 1 the user can be as sured that the source activity calibration has remained constant to within 0 1Ci and the error in the dwell time is less than 0 1 second See Table 3 Table 4 is based on the value of AK and can be used to determine which item e g source positioning or dwell time is i
8. is unserviceable or if the required service is cost prohibitive Products incurring service charges may be held for payment Standard Imaging does not provide loaner products See the Standard Imaging Warranty and Customer Responsibility for additional information Customer Responsibility This product and its components will perform properly and reliably only when operated and maintained in accordance with the instruc tions contained in this manual and accompa nying labels A defective device should not be used Parts which may be broken or missing or are clearly worn distorted or contaminated should be replaced immediately with genuine replacement parts manufactured by or made available from Standard Imaging Inc A caution Federal law in the U S A and Canadian law restrict the sale distribution or use of this product to by or on the order of a licensed medical practitioner The use of this product should be restricted to the supervision of a qualified medical physicist Measurement of high activ ity radioactive sources is potentially hazardous and should be performed by qualified personnel Should repair or replacement of this product become necessary after the warranty pe riod the customer should seek advice from Standard Imaging Inc prior to such repair or replacement If this product is in need of repair it should not be used until all repairs have been made and the product is function ing properly and ready for u
9. n error depending which value or values of K are out of criterion Table 2 Deviation of K and limits of error for QA Measurements QA Test AK lt 10 Source Positioning lt 0 5mm 10 lt AK lt 20 AK gt 20 0 5 lt x lt 1 0 mm gt 1 0 mm Table 3 Deviation of K and limits of error for QA Measurements QA Test AK lt 1 Source Activity Dwell Time 1 lt AK lt 2 AK gt 2 0 1 lt A lt 0 2 Ci 0 1 lt t lt 02s Table 4 Table for determining item in error depending on difference in value s of K Source of error appears as Source Activity Dwell Time Source Positioning minor major Where AK x AK x t Parameter AK x AK x AK x AK x are for current measurements and AK x t is an integrated measurement On means AK lt 1 and AK lt 10 Off means AK gt 1 and AK gt 10 Operational Procedure Note that the values of K are unique for your chamber and the electrometer used Your chamber and electrometer should be calibrated to give calibration values e g N unique to your setup The N value and the electrometer correction factors must be used as a multiplier for Q and in the above equa tions 1 and 2 for activity calibrations If the timer is suspected to be in error the timer accuracy can be determined at a plateau position Point B by measuring the charge accumulated in the amount of dwell time set on the HDR control The measured amount of
10. ovided holding device Secure the catheter with the knurled catheter holding device Note Take care not to kink the catheter and insure that the catheter is secured and unable to move If possible dedicate a catheter to this purpose and once locked in place let it remain in the QA tool The catheter should have a gentle arc when con nected to the HDR unit Moving the HDR unit can result in differences in the recorded values always keep the unit in the same position For greater rigidity a needle catheter is recommended Operational Procedure 3 The first time the tool is used take data to determine points A slope and B plateau as shown in Figure 2 to document the position onthe HDR system PointA should be where the reading equals about 0 5 of the difference between the maximum value and the trough value Point B should lie in the middle of the maximum plateau Program the HDR unit to begin 40 mm from the bottom of the well and move by the finest increments to 60 mm from the bottom stopping for 10 seconds at each dwell position Record the current reading at each position If your HDR unit is unable to determine millimeter sized steps reprogram the unit starting with different beginning loca tions to fill in the readings between the first set of dwell positions B Calculations for constant K Constant K can be determined from mea surements of the charge and current at Points A and B The concepts behind these c
11. radioactive source at the time of treatment the precision and consistency of the timer and the ability of the unit to position the source at the proper dwell location along the catheter Periodic quality assurance on HDR ma chines is a part of the standard protocol of the user The HDR QA tool for an HDR 1000 Plus well chamber is designed to verify the consistency of source positioning dwell time accuracy and source activity Wall Mount for QA Measurements A wall mount is available from Standard Imag ing for convenient mounting and storage of the HDR 1000 ion chamber It is important that the chamber be located in a consistent loca tion for QA measurements The QA tool can be placed in the open holder space in the wall mount that is next to the HDR 1000 chamber opening The HDR 1000 chamber can be con nected to a standard triax cable while mounted on the wall Note The HDR 1000 can be used mounted on the wall for QA measurements but should not be used any closer than 25 cm to any wall for calibration purposes See Medical Physics 19 1311 1314 1992 Refer to the Instruction Manual received with the HDR 1000 for calibration procedures Description Figure 1 shows a schematic drawing of the lead lined HDR QA tool insert This tool is inserted in the HDR 1000 Plus well chamber in place of the standard source holder insert The distance from the bottom of the tool to the center of the 4 mm spacer is 51 mm The HDR QA
12. roduct except consumables fuses batteries or glass breakage Standard Imaging Inc shall not be otherwise liable for any damages including but not limited to incidental damages consequential damages or special damages Repaired or replaced products are warranted for the balance of the original warranty period or at least 90 days This warranty is in lieu of all other warranties express or implied whether statutory or otherwise including any implied warranty of fitness for a particular purpose In no event shall Standard Im aging Inc be liable for any incidental or consequential damages resulting from the use misuse or abuse of the product or caused by any defect failure or malfunction of the product whether a claim of such damages is based upon the warranty contract negligence or otherwise This warranty represents the current standard warranty of Standard Imaging Inc Please refer to the labeling or instruction manual of your Standard Imaging Inc product or the Standard Imaging Inc web page for any warranty conditions unique to the product 12
13. se After repair the product may need to be calibrated The owner of this product has sole responsibility for any malfunction resulting from abuse improper use or maintenance or repair by anyone other than Standard Imaging Inc The information in this manual is subject to change without notice No part of this manual may be copied or reproduced in any form or by any means without prior written consent of Standard Imaging Inc Warranty Standard Imaging Inc sells this product under the warranty herein set forth The war ranty is extended only to the buyer purchasing the product directly from Standard Imaging Inc or as a new product from an authorized dealer or distributor of Standard Imaging Inc For a period provided in the table below from the date of original delivery to the pur chaser or a distributor this Standard Imaging Inc product provided in the table is warranted against functional defects in design materials and workmanship provided it is properly operated under conditions of normal use and that repairs and replace ments are made in accordance herewith The foregoing warranty shall not apply if the product has been altered disassembled or repaired other than by Standard Imag ing Inc or if the product has been subject to abuse misuse negligence or accident Product Warranty Period Standard Imaging lonization Chambers 2 years Standard Imaging Well Chambers 2 years Stand
14. time can be calculated from equa tions 1 and 2 as follows 3 Q B t Q B Q transit Where Q transit is the reading accumulated while the source moves into and returns from its dwell position Approaching this analogously to that typical of cobalt units define an effective transit time t such that gt efitr 4 LEA B Le teste Table 5 Example determining of f and t transit Q B t nc Average Std Dev Where B is a proportionality factor that should be equal to unity if the HDR timer is accurate te is the equivalent time to account for that part of the reading produced with the source in transit going to and returning from its dwell position t can be calculated by meas 5 t Q B t meas set 11 B To solve for the unknowns b and tans two different set times must be measured See Table 5 An assumption could be made that for ease of use in daily performance of the timer check the program should be stored on a program card or as a standard if the unit has these capabilities Dwell times in such stored programs often increase exponentially over time to compensate for radioactive decay of the source Thus this procedure should not be done see Med Phys 22 435 440 1995 for further explanations of Equations 4 and 5 for 8 separate measurements Q 924 t transit nC s 0 994 0 39 0 006 0 06 Operational Procedure C Standar
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