US3924129A
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US
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Method and apparatus for constructing a representation of a planar{3 s slice of body exposed to penetrating radiation
Assignee: QED Intellectual Property Ltd
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Filing: 1974-04-18
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Granted: 1975-12-02
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Expires: 1994-04-18
Abstract
Abstract In examining a body by means of X-rays or other penetrating radiation, signals are derived representing the logarithm of the absorption of individual beams in sets of parallel beams which are passed through the body in a single plane at many different angles. Corresponding to each such signal there is derived a summation signal produced by a process of convolution using a convolution function of a special form which is such that the convolution can be effected in a recirculatory circuit. An image of the plane section is reconstructed by selectively superimposing the summation signals producing the effect of what may be termed a compensated layergram.
Inventors
- 👤 Christopher Archibald Go Lemay
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 10:05
CPC Classifications
A; A61; A61B; A61B6/00; A61B6/40; A61B6/4064; A61B6/4071; A61B6/02; A61B6/03; A61B6/032; G; G06; G06T; G06T12/00; G06T12/20; Y; Y10; Y10S; Y10S378/00; Y10S378/901
Claims Analysis
Total Claims: 29
Claim 1
Independent Claim
351 words
A method of constructing a representation of the variation of absorption of a planar slice of a body with respect to penetrating radiation which comprises the steps of: a. providing a plurality of sets of m beam data signals where m is of the order of 50 or greater, the signals of each set being related to the logarithm of the absorption of a corresponding set of substantially parallel beams of said radiation in the plane of said slice, and the sets of signals corresponding effectively to sets of parallel beams, orientated at different angles in said plane, b. providing a series of factor signals of which the number of terms is of the order of the number m of effective beams per parallel set, said factor signals at least after the factor signal of order 5 conforming tO a substantially monotonic function, c. deriving for a particular beam data signal a summation signal by forming the sum of said beam data signal multiplied by the zero order factor signal, the next adjacent beam data signals of the same set multiplied by the first order factor signal, the second adjacent beam data signals of the same set multiplied by the second order factor signal and so on over a desired range, d. deriving for other beam data signals, some in every set, respective summation signals by repeating method step (c) in respect of each said other beam data signals, e. forming the sum of summation signals corresponding to beams of different sets intersecting a particular elementary area of the planar slice to produce a signal representing the absorption of said elementary area, f. repeating method step (e) in respect of other elementary areas of said planar slice, thereby to construct said representation, g. said substantially monotonic function being such that the signal representing the absorption of any elementary area is successively more accurately compensated for absorption suffered outside the respective elementary area by the beams intersecting the respective elementary area, as successively higher order factor signals multiplied by respective beam data signals are utilised in the formation of said summation signals.
Claim 2
Independent Claim
351 words
A method of constructing a representation of the variation of absorption of a planar slice of a body with respect to penetrating radiation which comprises the steps of: a. providing a plurality of sets of m beam data signals where m is of the order of 50 or greater, the signals of each set being related to the logarithm of the absorption of a corresponding set of substantially parallel beams of said radiation in the plane of said slice, and the sets of signals corresponding effectively to sets of parallel beams, orientated at different angles in said plane, b. providing a series of factor signals of which the number of terms is of the order of the number m of effective beams per parallel set, said factor signals at least after the factor signal of order 5 conforming tO a substantially monotonic function, c. deriving for a particular beam data signal a summation signal by forming the sum of said beam data signal multiplied by the zero order factor signal, the next adjacent beam data signals of the same set multiplied by the first order factor signal, the second adjacent beam data signals of the same set multiplied by the second order factor signal and so on over a desired range, d. deriving for other beam data signals, some in every set, respective summation signals by repeating method step (c) in respect of each said other beam data signals, e. forming the sum of summation signals corresponding to beams of different sets intersecting a particular elementary area of the planar slice to produce a signal representing the absorption of said elementary area, f. repeating method step (e) in respect of other elementary areas of said planar slice, thereby to construct said representation, g. said substantially monotonic function being such that the signal representing the absorption of any elementary area is successively more accurately compensated for absorption suffered outside the respective elementary area by the beams intersecting the respective elementary area, as successively higher order factor signals multiplied by respective beam data signals are utilised in the formation of said summation signals.
Claim 3
Dependent Claim
36 words
A method according to claim 1 in which one or more of the lower order factor signals exhibits a departure from said substantially monotonic function which is such as to produce the effect of aperture correction.
Claim 4
Dependent Claim
47 words
A method according to claim 2 in which one or more lower order factor signals define a oscillatory component superimposed on said substantially monotonic function which is such as to produce an overshoot in said representation in response to a step function in said variation of absorption.
Claim 5
Dependent Claim
81 words
A method according to claim 1 which includes the step of multiplying beam data signals, taken set by set, by said factor signals in a serial process in which each beam data signal of a set is multiplied successively by the factor signals up to the order required to derive the summation signals, and the products are selectively accumulated in a plurality of storage locations, one for each summation signal, in such a way as to derive the respective summation signals.
Claim 6
Dependent Claim
51 words
A method according to claim 4 in which the successive multiplications of the different beam data signals of a set overlap in time in such a way that groups of product signals which have to be accommodated in the same storage location are formed within the time required for one multiplication.
Claim 7
Dependent Claim
56 words
A method according to claim 4 in which the beam data signals of a set taken in one order are each multiplied successively by respective factor signals, taken in order, and the product signals are accumulated in the same row of storage locations, the products being shifted sideways by one place for each beam data signal.
Claim 8
Dependent Claim
107 words
A method according to claim 5 in which successive multiplications by the same multiplier are performed firstly on a beam data signal and thereafter on the successive products, the multiplier being of magnitude less than unity and being such that the products of successive multiplications approximate to the products of said beam data signal multiplied by successive factor signals, and in which further beam data signals are added to successive products so as to be subjected to overlapping multiplications in such a way that said groups of product signals which have to be accumulated are produced substantially simultaneously and are automatically accumulated in the process of multiplication.
Claim 9
Independent Claim
324 words
A method of constructing a representation of the variation of absorption of a planar slice of a body with respect to penetrating radiation which comprises the steps of: a. providing a plurality of sets of m beam data signals where m is of the order of 50 or greater, the signals of each set representing tHe logarithm of the absorption of a corresponding set of substantially parallel beams of said radiation in the plane of said slice, and the sets of signals corresponding effectively to sets of parallel beams, orientated at different angles in said plane, b. providing a series of factor signals of which the number of terms is of the order of the number m of effective beams per parallel set, said factor signals being derived from a convolution function including an oscillating component affecting on the initial part of said convolution function, c. deriving for a particular beam data signal a summation signal by forming the sum of said beam data signal multiplied by the zero order factor signal, the next adjacent beam data signals of the same set multiplied by the first order factor signal, the second adjacent beam data signals of the same set multiplied by the second order factor signal and so on over a desired range, d. deriving for other beam data signals, some in every set, respective summation signals by repeating method step (c) in respect of each said other beam data signals, e. forming the sum of summation signals corresponding to beams of different sets intersecting a particular elementary area of the planar slice to produce a signal representing the absorption of said elementary area, f. repeating method step (e) in respect of other elementary areas of said planar slice, thereby to construct said representation, g. said oscillatory component including in the convolution function being such as to produce an overshoot in said representation in response to a step function in said variation of absorption.
Claim 10
Independent Claim
324 words
A method of constructing a representation of the variation of absorption of a planar slice of a body with respect to penetrating radiation which comprises the steps of: a. providing a plurality of sets of m beam data signals where m is of the order of 50 or greater, the signals of each set representing tHe logarithm of the absorption of a corresponding set of substantially parallel beams of said radiation in the plane of said slice, and the sets of signals corresponding effectively to sets of parallel beams, orientated at different angles in said plane, b. providing a series of factor signals of which the number of terms is of the order of the number m of effective beams per parallel set, said factor signals being derived from a convolution function including an oscillating component affecting on the initial part of said convolution function, c. deriving for a particular beam data signal a summation signal by forming the sum of said beam data signal multiplied by the zero order factor signal, the next adjacent beam data signals of the same set multiplied by the first order factor signal, the second adjacent beam data signals of the same set multiplied by the second order factor signal and so on over a desired range, d. deriving for other beam data signals, some in every set, respective summation signals by repeating method step (c) in respect of each said other beam data signals, e. forming the sum of summation signals corresponding to beams of different sets intersecting a particular elementary area of the planar slice to produce a signal representing the absorption of said elementary area, f. repeating method step (e) in respect of other elementary areas of said planar slice, thereby to construct said representation, g. said oscillatory component including in the convolution function being such as to produce an overshoot in said representation in response to a step function in said variation of absorption.
Claim 11
Independent Claim
336 words
A method of constructing a representation of the variation of absorption of a planar slice of a body with respect to penetrating radiation which comprises the steps of: a. providing a plurality of sets of beam data signals, the signals of each set representing the logarithm of the absorption of a corresponding set of substantially parallel beams of said radiation in the plane of said slice, and the sets of signals corresponding effectively to sets of parallel beams oriented at different angles in said plane, b. providing a series of factor signals from zero order upward derived from a convolution function, c. deriving for a particular beam data signal a summation signal by forming the sum of said beam data signal multiplied by the zero order factor signal, the next adjacent beam data signals of the same set multiplied by the first order factor signal, the second adjacent beam data signals of the same set multiplied by the second order factor signal, and so on to the limits of the set or the highest order factor signal, d. deriving for other beam data signals, some in every set, respective summation signals by repeating method step (c) in respect of each said other beam data signal, e. the multiplication required to form the summation signals being performed on the beam data signals taken in sets, the beam data signals of a set being subjected each to a series of multiplications by said factor signals and the series of multiplications of the different signals of one set overlapping each other in time in such a way that groups of products which have to be accumulated are formed within the time required for one multiplication, f. forming the sum of summation signals corresponding to beams of different sets intersecting a particular elementary area of the planar slice to produce a signal representing the absorption of said elementary area, g. and repeating method step (f) in respect of other elementary areas of said planar slice, thereby to construct said representation.
Claim 12
Independent Claim
336 words
A method of constructing a representation of the variation of absorption of a planar slice of a body with respect to penetrating radiation which comprises the steps of: a. providing a plurality of sets of beam data signals, the signals of each set representing the logarithm of the absorption of a corresponding set of substantially parallel beams of said radiation in the plane of said slice, and the sets of signals corresponding effectively to sets of parallel beams oriented at different angles in said plane, b. providing a series of factor signals from zero order upward derived from a convolution function, c. deriving for a particular beam data signal a summation signal by forming the sum of said beam data signal multiplied by the zero order factor signal, the next adjacent beam data signals of the same set multiplied by the first order factor signal, the second adjacent beam data signals of the same set multiplied by the second order factor signal, and so on to the limits of the set or the highest order factor signal, d. deriving for other beam data signals, some in every set, respective summation signals by repeating method step (c) in respect of each said other beam data signal, e. the multiplication required to form the summation signals being performed on the beam data signals taken in sets, the beam data signals of a set being subjected each to a series of multiplications by said factor signals and the series of multiplications of the different signals of one set overlapping each other in time in such a way that groups of products which have to be accumulated are formed within the time required for one multiplication, f. forming the sum of summation signals corresponding to beams of different sets intersecting a particular elementary area of the planar slice to produce a signal representing the absorption of said elementary area, g. and repeating method step (f) in respect of other elementary areas of said planar slice, thereby to construct said representation.
Claim 13
Dependent Claim
349 words
Apparatus for constructing a representation of the variation of absorption of a planar slice of a body with respect to penetrating radiation which comprises: a. a source of a plurality of sets of m beam data signals where m is of the order of 50 or greater, the signals of each set representing the logArithm of the absorption of a corresponding set of substantially parallel beams of said radiation in the plane of said slice, and the sets of signals corresponding effectively to sets of parallel beams, orientated at different angles in said plane, b. a source of a series of factor signals of which the number of terms is of the order of the number m of effective beams per parallel set, said factor signals at least after the factor signal of order 5 conforming to a substantially monotonic function, c. derivation means for deriving respective summation signals for a plurality of beam data signals, some in every set, said derivation means including means for forming, for each of said plurality of beam data signals, the sum of the respective beam data signal multiplied by the zero order factor signal, the next adjacent beam data signals of the same set multiplied by the first order factor signal, the second adjacent beam data signals of the same set multiplied by the second order factor signal and so on over a desired range, thereby to derive the summation signal for each of said plurality of beam data signals. d. and means for forming the sum of summation signals corresponding to beams of different sets intersecting each of a plurality of elementary areas of the planar slice to produce signals representing the absorption of said elementary area, thereby to construct said representation, e. said substantially monotonic function being such that the signal representing the absorption of any elementary area is successively more accurately compensated for absorption suffered outside the respective elementary area by the beams intersecting the respective elementary area, as successively higher order factor signals multiplied by respective beam data signals are utilised in the formation of said summation signals.
Claim 14
Dependent Claim
349 words
Apparatus for constructing a representation of the variation of absorption of a planar slice of a body with respect to penetrating radiation which comprises: a. a source of a plurality of sets of m beam data signals where m is of the order of 50 or greater, the signals of each set representing the logArithm of the absorption of a corresponding set of substantially parallel beams of said radiation in the plane of said slice, and the sets of signals corresponding effectively to sets of parallel beams, orientated at different angles in said plane, b. a source of a series of factor signals of which the number of terms is of the order of the number m of effective beams per parallel set, said factor signals at least after the factor signal of order 5 conforming to a substantially monotonic function, c. derivation means for deriving respective summation signals for a plurality of beam data signals, some in every set, said derivation means including means for forming, for each of said plurality of beam data signals, the sum of the respective beam data signal multiplied by the zero order factor signal, the next adjacent beam data signals of the same set multiplied by the first order factor signal, the second adjacent beam data signals of the same set multiplied by the second order factor signal and so on over a desired range, thereby to derive the summation signal for each of said plurality of beam data signals. d. and means for forming the sum of summation signals corresponding to beams of different sets intersecting each of a plurality of elementary areas of the planar slice to produce signals representing the absorption of said elementary area, thereby to construct said representation, e. said substantially monotonic function being such that the signal representing the absorption of any elementary area is successively more accurately compensated for absorption suffered outside the respective elementary area by the beams intersecting the respective elementary area, as successively higher order factor signals multiplied by respective beam data signals are utilised in the formation of said summation signals.
Claim 15
Dependent Claim
34 words
Apparatus according to claim 10 in which one or more of the lower order factor signals exhibits a departure from said monotonic function which is such as to produce the effect of aperture correction.
Claim 16
Dependent Claim
79 words
Apparatus according to claim 10 including means for multiplying beam data signals, taken set by set, by said factor signals in a serial process in which each beam data signal of a set is multiplied successively by the factor signals up to the order required to derive the summation signals, and means for selectively accumulating the products in a plurality of storage locations, one for each summation signal, in such a way as to derive the respective summation signals.
Claim 17
Dependent Claim
59 words
Apparatus according to claim 12 in which said multiplying means is so arranged that in operation the successive multiplications of the different beam data signals of a set overlap in time in such a way that groups of product signals which have to be accumulated in the same storage location are formed within the time required for one multiplication.
Claim 18
Dependent Claim
123 words
Apparatus according to claim 12 in which said multiplying means includes a recirculating network for performing successive multiplications by the same multiplier, such multiplications being performed firstly on a beam data signal and thereafter on the successive products, the multiplier of said network being of magnitude less than unity and being such that the products of successive multiplications approximate to the products of said beam data signal multiplied by successive factor signals, and means for adding further beam data signals to successive products so that the initial and added beam data signals are subjected to overlapping multiplications in such a way that said groups of product signal which have to be accumulated are produced substantially simultaneously and are automatically accumulated in multiplying means.
Claim 19
Dependent Claim
35 words
Apparatus according to claim 14 in which said recirculating network has a delay time which is equal to the interval separating the application of successive beam data signals of a set to said recirculating network.
Claim 20
Dependent Claim
22 words
Apparatus according to claim 15 in which said recirculating network incluDes a plurality of parallel branches producing multiplication by different partial multipliers.
Claim 21
Dependent Claim
20 words
Apparatus according to claim 14 including means for adding a correction to certain of the products of group recirculating network.
Claim 22
Dependent Claim
340 words
Apparatus for constructing a representation of the variation of absorption of a planar slice of a body with respect to penetrating radiation which comprises: a. a source of a plurality of sets of beam data signals, the signals of each set representing the logarithm of the absorption of a corresponding set of substantially parallel beams of said radiation in the plane of said slice, and the sets of signals corresponding to sets of parallel beams orientated at different angles in said plane, b. a source of a series of factor signals from zero order upward derived from a convolution function, c. derivation means for deriving respective summation signals for a plurality of beam data signals, some in every set, said derivation means including means for forming for each of said plurality of beam data signals, the sum of the respective beam data signal multiplied by the zero order factor signal, the next adjacent beam data signals of the same set multiplied by the first order factor signal, the second adjacent beam data signals of the same set multiplied by the second order factor signal, and so on over a desired range, thereby to derive the summation signal for each of said plurality of beam data signals, d. said derivation means further including multiplying means so arranged that in operation the multiplications required to form the summation signals are performed on the beam data signals taken in sets, the beam data signals of a set being subjected each to a series of multiplications by said factor signals and the series of multiplications of the different beam data signals of one set overlapping each other in time in such a way that groups of products which have to be accumulated are formed within the time required for one multiplication. e. means for forming the sum of summation signals corresponding to beams of different sets intersecting each of a plurality of elementary areas of the planar slice to produce a signal representing the absorption of said elementary area, thereby to conduct said representation.
Claim 23
Dependent Claim
340 words
Apparatus for constructing a representation of the variation of absorption of a planar slice of a body with respect to penetrating radiation which comprises: a. a source of a plurality of sets of beam data signals, the signals of each set representing the logarithm of the absorption of a corresponding set of substantially parallel beams of said radiation in the plane of said slice, and the sets of signals corresponding to sets of parallel beams orientated at different angles in said plane, b. a source of a series of factor signals from zero order upward derived from a convolution function, c. derivation means for deriving respective summation signals for a plurality of beam data signals, some in every set, said derivation means including means for forming for each of said plurality of beam data signals, the sum of the respective beam data signal multiplied by the zero order factor signal, the next adjacent beam data signals of the same set multiplied by the first order factor signal, the second adjacent beam data signals of the same set multiplied by the second order factor signal, and so on over a desired range, thereby to derive the summation signal for each of said plurality of beam data signals, d. said derivation means further including multiplying means so arranged that in operation the multiplications required to form the summation signals are performed on the beam data signals taken in sets, the beam data signals of a set being subjected each to a series of multiplications by said factor signals and the series of multiplications of the different beam data signals of one set overlapping each other in time in such a way that groups of products which have to be accumulated are formed within the time required for one multiplication. e. means for forming the sum of summation signals corresponding to beams of different sets intersecting each of a plurality of elementary areas of the planar slice to produce a signal representing the absorption of said elementary area, thereby to conduct said representation.
Claim 24
Dependent Claim
338 words
Apparatus for constructing a representation of the variation of absorption of a planar slice of a body with respect to penetrating radiation which comprises: a. a source of a plurality of sets of m beam data signals m is of the order of 50 or greater, the signals of each set representing the logarithm of the absorption of a corresponding set of substantially parallel beams of said radiation in the plane of said slice, and the sets of signals corresponding effectively to sets of parallel beams, orientated at different angles in said plane, b. a source of a series of factor signals of which the number of terms is of the order of the number m of effective beams per parallel set, said factor signals being derived from a convolution function including an oscillatory component affecting on the initial part of the convolution function so as to affect one or more of the first group of factor signals, c. derivation means for deriving respective summation signals for a plurality of beam data signals, some in every set, said derivation means including means for forming, for each of said plurality of beam data signals, the sum of the respective beam data signal multiplied by the zero order factor signals, the next adjacent beam data signals of the same set multiplied by the first order factor signal, the second adjacent beam data signals of the same set multiplied by the second order factor signal and so on over a desired range, therby to derive the summation signal for each of said plurality of beam data signals, d. and means for forming the sum of summation signals corresponding to beams of different sets intersecting each of a plurality of elementary areas of the planaR slice to produce signals representing the absorption of said elementary area, thereby to construct said representation, e. said oscillatory component included in on the convolution function being such as to produce an overshoot in said representation in response to a step function in said variation of absorption.
Claim 25
Dependent Claim
338 words
Apparatus for constructing a representation of the variation of absorption of a planar slice of a body with respect to penetrating radiation which comprises: a. a source of a plurality of sets of m beam data signals m is of the order of 50 or greater, the signals of each set representing the logarithm of the absorption of a corresponding set of substantially parallel beams of said radiation in the plane of said slice, and the sets of signals corresponding effectively to sets of parallel beams, orientated at different angles in said plane, b. a source of a series of factor signals of which the number of terms is of the order of the number m of effective beams per parallel set, said factor signals being derived from a convolution function including an oscillatory component affecting on the initial part of the convolution function so as to affect one or more of the first group of factor signals, c. derivation means for deriving respective summation signals for a plurality of beam data signals, some in every set, said derivation means including means for forming, for each of said plurality of beam data signals, the sum of the respective beam data signal multiplied by the zero order factor signals, the next adjacent beam data signals of the same set multiplied by the first order factor signal, the second adjacent beam data signals of the same set multiplied by the second order factor signal and so on over a desired range, therby to derive the summation signal for each of said plurality of beam data signals, d. and means for forming the sum of summation signals corresponding to beams of different sets intersecting each of a plurality of elementary areas of the planaR slice to produce signals representing the absorption of said elementary area, thereby to construct said representation, e. said oscillatory component included in on the convolution function being such as to produce an overshoot in said representation in response to a step function in said variation of absorption.
Claim 26
Independent Claim
168 words
A method of constructing a representation of the variations of absorption of a planar slice of a body with respect to penetrating radiation which comprises the steps of a. acquiring a plurality of sets of beam data signals, the signals of each set representing the logarithm of the absorption of a corresponding set of parallel beams of said radiation, in the plane of said slice, and the sets of signals corresponding effectively to parallel sets of beams orientated at different angles, b. the acquisition of said signals being carried out by a sampling process which causes adjacent beams of a set to overlap substantially and to have an intensity distribution across their width which declines to either side from a maximum value adjacent to the centre of the beam, c. correlating said beam signals with signals conforming to an inverting function and adding the correlated signals in such a way as to give the effect of an inverting operation, d. utilising the resultant signal to construct said representation.
Claim 27
Independent Claim
168 words
A method of constructing a representation of the variations of absorption of a planar slice of a body with respect to penetrating radiation which comprises the steps of a. acquiring a plurality of sets of beam data signals, the signals of each set representing the logarithm of the absorption of a corresponding set of parallel beams of said radiation, in the plane of said slice, and the sets of signals corresponding effectively to parallel sets of beams orientated at different angles, b. the acquisition of said signals being carried out by a sampling process which causes adjacent beams of a set to overlap substantially and to have an intensity distribution across their width which declines to either side from a maximum value adjacent to the centre of the beam, c. correlating said beam signals with signals conforming to an inverting function and adding the correlated signals in such a way as to give the effect of an inverting operation, d. utilising the resultant signal to construct said representation.
Claim 28
Dependent Claim
135 words
Apparatus for constructing a representation of the variation of absorption of a planar slice of a body with respect to penetrating radiation which comprises: a. means for exploring the body in said plane with penetrating radiation, b. means for detecting the intensity of collimated beams of said radiation after passing through the body, c. means for sampling the outputs of the detecting means in such manner as to present output signals corresponding to the absorption or transmission of parallel beams of said radiation which beams substantially overlap and have an intensity distribution which declines to either side from a maximum value adjacent the center of the respective beam, d. means for providing processing signals representing values of an inverting function, e. means for processing said output signals utilising said processing signals to produce said representation.
Claim 29
Dependent Claim
135 words
Apparatus for constructing a representation of the variation of absorption of a planar slice of a body with respect to penetrating radiation which comprises: a. means for exploring the body in said plane with penetrating radiation, b. means for detecting the intensity of collimated beams of said radiation after passing through the body, c. means for sampling the outputs of the detecting means in such manner as to present output signals corresponding to the absorption or transmission of parallel beams of said radiation which beams substantially overlap and have an intensity distribution which declines to either side from a maximum value adjacent the center of the respective beam, d. means for providing processing signals representing values of an inverting function, e. means for processing said output signals utilising said processing signals to produce said representation.
References Cited (Backward Citations)
US3778614A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-12-01 | 1979-06-02 | 1979-12-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-12-01 | 1983-06-02 | 1983-12-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-12-01 | 1987-06-02 | 1987-12-02 | $7700.00 | Window Closed / Lapsed |