1、Designation: F2554 10Standard Practice forMeasurement of Positional Accuracy of Computer AssistedSurgical Systems1This standard is issued under the fixed designation F2554; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year o
2、f last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice addresses the techniques of measurementand reporting of basic static performance (accuracy, repeatabil
3、-ity, and so forth) of surgical navigation and/or robotic posi-tioning devices under defined conditions. The scope covers thetracking subsystem, testing only in this practice the accuracyand repeatability of the system to locate individual points inspace. A point in space has no orientation; only mu
4、lti-dimensional objects have orientation. Therefore, orientation ofobjects is not within the scope of this practice. However, inlocalizing a point the different orientations of the localizationtool can produce errors. These errors and the orientation of thelocalization tool are within the scope of t
5、his practice. The aimis to provide a standardized measurement of performancevariables by which end-users can compare within (for example,different fixed reference frames or stylus tools) and between(for example, different manufacturers) different systems. Pa-rameters to be evaluated include (based u
6、pon the features of thesystem being evaluated):(1) Location of a point relative to a coordinate system.(2) Relative point to point accuracy (linear).(3) Repeatability of coordinates of a single point.(4) For an optically based system, the range of visibleorientations of the reference frames or tools
7、.(5) This method covers all configurations of tool arrays inthe system.1.2 The system as defined in this practice includes only thetracking subsystem (optical, magnetic, mechanical, and soforth) stylus, computer, and necessary hardware and software.As such, this practice incorporates tests that can
8、be applied toa prescribed phantom model in a laboratory or controlledsetting.1.3 This practice defines a standardized reporting format,which includes definition of the coordinate systems to be usedfor reporting the measurements, and statistical measures (forexample, mean, standard deviation, maximum
9、 error).1.4 This practice will serve as the basis for subsequentstandards for specific tasks (cutting, drilling, milling, reaming,biopsy needle placement, and so forth) and surgical applica-tions.1.5 The values stated in SI units are to be regarded asstandard. No other units of measurement are inclu
10、ded in thisstandard.1.6 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to
11、 use.2. Referenced Documents2.1 ASTM Standards:2E456 Terminology Relating to Quality and StatisticsE2281 Practice for Process and Measurement CapabilityIndices2.2 Other References:ISO 10360 Geometrical Product Specifications (GPS)Acceptance and Reverification Tests for Coordinate Mea-suring Machines
12、 (CMM)3. Terminology3.1 Definition of Terms Specific to Accuracy Reporting:3.1.1 accuracy, nthe closeness of agreement between ameasurement result and an accepted reference value. E4563.1.1.1 DiscussionThe term accuracy, when applied to aset of measurement results, involves a combination of arandom
13、component and of a common systematic error or biascomponent.3.1.2 bias, nthe difference between the expectation of themeasurement results and an accepted reference value. E4561This practice is under the jurisdiction ofASTM Committee F04 on Medical andSurgical Materials and Devices and is the direct
14、responsibility of SubcommitteeF04.38 on Computer Assisted Orthopaedic Surgical Systems.Current edition approved Dec. 1, 2010. Published January 2011. DOI 10.1520/F255410.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annu
15、al Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.1.2.1 DiscussionBias is the total systematic error ascontrasted to random
16、error. There may be one or moresystematic error components contributing to the bias. A largersystematic difference from the accepted reference value isreflected by a larger bias value.3.1.3 maximum error, nthe largest distance between anymeasured point and its corresponding reference position (forex
17、ample, as measured by CMM) for any trial during a testingprocedure.3.1.4 mean, nthe arithmetic mean (or simply the mean) ofa list of numbers is the sum of all the members of the listdivided by the number of items in the list. If one particularnumber occurs more times than others in the list, it is c
18、alled amode. The arithmetic mean is what students are taught veryearly to call the “average”. If the list is a statistical population,then the mean of that population is called a population mean.If the list is a statistical sample, we call the resulting statistic asample mean.3.1.5 measurement range
19、, nsee measurement volume.3.1.6 precision, nthe closeness of agreement betweenindependent measurement results obtained under stipulatedconditions. E4563.1.6.1 DiscussionPrecision depends on random errorsand does not relate to the true value or the specified value. Themeasure of precision usually is
20、expressed in terms of impreci-sion and computed as a standard deviation of the test results.The standard deviation is expressed as:S 5(i51NXi X!2N 1Less precision is reflected by a larger standard deviation.“Independent test results” means results obtained in a mannernot influenced by any previous r
21、esult on the same or similartest object. Quantitative measure of precision depends criti-cally on the stipulated conditions. Repeatability and reproduc-ibility conditions are particular sets of extreme stipulatedconditions.3.1.7 range, R, nthe largest observation minus the small-est observation in a
22、 set of values or observations. E456,E22813.1.8 repeatability, nprecision under repeatability condi-tions. E4563.1.8.1 DiscussionRepeatability is one of the concepts orcategories of the precision of a test method. Measures ofrepeatability defined in this compilation are repeatability,standard deviat
23、ion, and repeatability limit.3.1.9 reproducibility, nprecision under reproducibilityconditions. E4563.1.9.1 DiscussionAbility of a test or experiment to beaccurately reproduced, or replicated.3.1.10 resolution, nof a device/sensor, the smallestchange the device or sensor can detect in the quantity t
24、hat it ismeasuring. The resolution is related to the precision withwhich the measurement is made.3.1.11 standard deviation, nthe most usual measure of thedispersion of observed values or results expressed as thepositive square root of the variance. E4563.1.12 variance, nof a random variable, measure
25、 of itsstatistical dispersion, indicating how its possible values arespread around the expected value. Where the expected valueshows the location of the distribution, the variance indicatesthe scale of the values. A more understandable measure is thesquare root of the variance, called the standard d
26、eviation.3.2 Definition of Terms Specific to Surgical Navigation andRobotic Positioning Systems:3.2.1 data integrity, ncondition in which data is identi-cally maintained during any operation, such as transfer, stor-age, and retrieval.3.2.2 degree of freedom (DOF), nset of independentdisplacements th
27、at specify completely the displaced or de-formed position of the body or system.3.2.3 dynamic reference base, na reference element that isintraoperatively attached to a therapeutic object and allowstracking that object. It defines the local coordinate system ofthe therapeutic object.3.2.4 fiducial,
28、nan artificial object (for example, screw orsphere) that is implanted into, or a feature created on, atherapeutic object prior to virtual object acquisition to facilitateregistration.3.2.5 marker, na single 3-degree-of-freedom indicator ona reference element or dynamic reference base.3.2.6 measureme
29、nt volume, nmeasuring range of atracker, stated as simultaneous limits on all spatial coordinatesmeasured by the tracker. ISO 10360-13.2.7 navigation system, na device consisting of a com-puter with associated software and a localizer that tracksreference elements attached to surgical instruments or
30、 implantsas well as one or more dynamic reference bases attached to thetherapeutic object. It provides real-time feedback of the per-formed action by visualizing it within the virtual environment.3.2.8 reference element, na device attached to surgicalinstruments and implants and other devices that e
31、nablesdetermination of position and orientation in 3d space (up to 6degrees of freedom) of these by means of a tracker. It definesthe local coordinate system of this instrument or implant.3.2.9 referencing, ntracking of a therapeutic object bymeans of a dynamic reference base.3.2.10 registration, nt
32、he determination of the transforma-tion between the coordinate spaces of the therapeutic andvirtual objects or between the coordinate spaces of two virtualobjects. A registration is rigid if it consists only of rotations,translations, and scaling; it is non-rigid if it also compriseslocal or global
33、distortions.3.2.11 robotic positioning system, nuse of an active me-chanical (mechatronic) device to position an instrument guideat a specified location in 3d space (up to 6 degrees of freedom).3.2.12 stylus, na mechanical device consisting of a stylustip and a shaft. The stylus tip is the physical
34、element thatestablishes the contact with the workpiece. ISO 10360-13.2.13 tool calibration, nthe pre- or intraoperative deter-mination of the location of points-of-interest on a navigatedinstrument (for example, its tip position, axis) in relation to areference frame (for example, the attached refer
35、ence elementfor a tracked instrument).F2554 1023.2.14 tracker, na device that measures the spatial loca-tion and orientation of surgical instruments implants, or thetherapeutic object that are instrumented with reference ele-ments or a dynamic reference base respectively. A tracker maymeasure based
36、on infrared light (see tracking, active andtracking, passive), ultrasound, electromagnetic fields, mechani-cal linkage, video streams, and so forth.3.2.15 tracking, active, na tracking technology that usesmarkers that emit energy (for example, an infrared light basedtracking technology that uses pul
37、sed LEDs as markers, ultra-sound, electromagnetic fields, and so forth).3.2.16 tracking, passive, na tracking technology that usesmarkers that absorb or reflect externally produced energy. (forexample, an light based tracking technology that uses reflectivespheres or similar objects as markers).3.3
38、Others:3.3.1 computer assisted surgery (CAS), nthe use of com-puters to facilitate or enhance Surgical Procedures via the useof three-dimensional space tracking of objects.3.3.2 coordinate measuring machine (CMM), nmeasuringsystem with the means to move a stylus and capability todetermine spatial co
39、ordinates on a work piece surface.ISO 10360-13.3.3 phantom, nstandardized measurement object. SeeAppendix X1 for recommendations regarding phantom design.Specific points referenced in this practice are with regards tothe recommended phantom design in Appendix X1.4. Summary of Practice4.1 This practi
40、ce provides recommendations for the collec-tion, analysis, and presentation of data regarding the positionalaccuracy of surgical navigation and robotic positioning sys-tems.4.2 Data to be provided include measured statistical distri-bution, maximum error, mean, and standard deviations, 5th and95th p
41、ercentiles of location and orientation accuracy.4.3 This practice provides protocols (Section 8) for measur-ing accuracy of the tracking system (optical, magnetic, me-chanical, and so forth) made under repeatable conditions.Subsequent standards will address the system along with anynecessary imaging
42、 modality (fluoroscopy, computed tomogra-phy, magnetic resonance imaging, ultrasound, and so forth) forimage based systems, and the software for registering theimages or the imageless data to the patient. Additional stan-dards will also address task specific procedures and surgicalapplications (join
43、t arthroplasty, osteotomy, tumor biopsyand/or resection, laproscopy, pedicle screw insertion, brainsurgery, and so forth).5. Significance and Use5.1 The purpose of this practice is to provide data that canbe used for evaluation of the accuracy of different CASsystems.5.2 The use of surgical navigati
44、on and robotic positioningsystems is becoming increasingly common and requires adegree of trust by the user that the data provided by the systemmeets necessary accuracy requirements. In order to evaluatethe potential use of these systems, and to make informeddecisions about suitability of a system f
45、or a given procedure,objective performance data of such systems are necessary.While the end user will ultimately want to know the accuracyparameters of a system under clinical application, the first stepmust be to characterize the digitization accuracy of the trackingsubsystem in a controlled enviro
46、nment under controlled con-ditions.5.3 In order to make comparisons within and betweensystems, a standardized way of measuring and reportingaccuracy is needed. Parameters such as coordinate system,units of measure, terminology, and operational conditions mustbe standardized.6. Apparatus6.1 Standardi
47、zed measurement object (phantom). See X1.1.6.2 System to be evaluated, including tracking system,stylus, and associated required hardware and software. Whilethe software may be custom written for the tasks outlined inthis practice it should use the same algorithms and methodolo-gies being implemente
48、d in the commercial/clinical system tobe assessed.7. Hazards7.1 None.8. Procedure8.1 A standardized measurement object (phantom) mea-sured with a CMM or similar measurement device calibrated toa traceable standard, will be used to evaluate the accuracy ofthe tracking subsystem. The resolution of thi
49、s measurementdevice will determine the significant digits that can be reportedin the results See Appendix X1 for phantom recommendations.The accuracy of the measurement device must be at least 43,and preferably 103, as accurate as the anticipated accuracy tobe reported.8.2 Rigid attachment of a dynamic reference base to thephantom is to be performed according to navigation systemmanufacturers recommendations. Once testing has begun, thedynamic reference base should not be repositioned relative tothe phantom. Note that some systems, such as Ro
