DE2158535A1 - Radiation treatment device - Google Patents

Description

to output dose parameters of the defined radiation treatment plan. Is is a possibility of writing and updating provided so that the Behandltmgsplan edited and with the cumulative radiation dose updated v / can ground that each portal is administered _s and ax of the total cumulative dose which has been administered to the patient "Each parameter of an intended treatment plan is compared with the permissible ranges of device parameters, which are stored in a memory, in order to ensure that the intended treatment is within the permissible range of the device. Position signals are derived from the various movable controls and parts of the beam device. The prescribed treatment parameters are compared with the actual settings of the elements and controls of the machine in order to obtain a locking signal if at least one of these actual parameters differs from the corresponding prescribed parameter. The locking signal is used to prevent irradiation of the patient until the fenler is eliminated * In addition, the computer has a collision avoidance program that avoids a collision between the bed or the patient and the frame.

Starting point of, invention;

The mechanical preparation of a radiation treatment device has already been automated to reduce the set-up time and reduce the accuracy of the mechanical adjustment for radiation treatment to improve. In the known device, the desired position information was for the mechanical adjustment of the machine according to a prescribed treatment plan in cards

209824/0952

punched. A deck of cards representing the setting for the prescribed treatment plan was in introduced a card reader. The output of the card reader was fed to control circuits to control the mechanical movements from various movable parts of the device to control one after the other in order to geometrically shape the frame and the treatment bed according to the prescribed treatment plan to position. The cards were read one by one. A four-digit display was provided about the position of each of the mechanically movable elements of the radiation treatment device.

This well-known automated radiation treatment device Significantly reduced set-up times and improved setting accuracy, but errors persisted possible by the operating personnel or the device because the operating personnel read the positions of the Had to compare various movable elements with a treatment plan to see if each of the elements is in the desired position. In addition, the operating personnel must determine the treatment time for the radiation dose Adjust according to the treatment plan so that there is another possibility of mistake. The well-known The device did not have a facility to automatically maintain an updated reading of the cumulative radiation dose that had been given to a patient through a prescribed radiation portal was still being a \ -omatically maintain a cumulative sum of the total radiation administered to a given patient had been. The prescribed treatment plan for one With the known device, patients could be edited and updated by punching a new set of punched cards became. However, mistakes could be made by the punch and these mistakes then appeared in the treatment plan for the patient.

20982470952

I'm another problem with the well-known automated The radiation treatment device was that the adjustment was made one after the other, so that before the start of the movement one element the setting for another element had to be finished. For example, the rotation of the The frame should be finished before the bed could be rotated into the desired position.

It is desirable to have an improved automated radiation treatment device to get »that automatically a designated treatment plan against an area allowable fourth tests to prevent a treatment plan from being set or edited that does not comply with a predetermined scope of permissible fourth for each parameter of a treatment plan is in agreement. It is also desirable to have an improved To have automated radiation treatment device available that automatically does the geometric and control setting compares the device to a prescribed treatment plan to find an indication of a discrepancy between to maintain these two so that operator errors are minimized. It 1st furthermore, it is desirable to reduce the set-up time of the radiation treatment device even further than with the known device, so that a larger number of patients can be treated with one device in a given time.

Summary of the Invention;

The invention aims to provide an improved automated radiation treatment device.

According to the invention, a device is provided with which the treatment plan for a patient automatically with regard to the cumulative sum of the radiation dose edited

209824/0952

and updated that administered to the particular patient if that was the case.

According to a special embodiment of the invention, the device for automatic editing and updating of the patient's treatment plan on a programmed general purpose computer.

According to a special training dor invention is a Data view input and output device or a teleprinter connection connected to a general-purpose computer as a dialog data station in order to edit the updated treatment plan, read and output.

According to a particular embodiment of the invention is information that a radiation treatment plan for a particular Defined patient, in a first memory, for example a magnetic tape cassette, a punched tape or a magnetic disk. This information will transferred to the memory of the computer and the computer reads the stored information on command to a reading and output station, which is set up to receive the treatment plan information, which is saved in the computer.

According to a further development of the invention, information is stored, the permissible range of values of machine parameters for a treatment plan, and the corresponding parameters of an intended treatment plan compared with the stored range of permissible values, to derive a locking signal when the value of an intended machine parameter is outside the permissible range of values. The lock signal is used to transfer the intended treatment parameters in the treatment plan for the patient.

209824/0952

According to another development of the invention, devices are provided with which automatically the setting of the radiation device with the intended treatment plan a comparison is made and any discrepancy between the two is detected and an interlock signal is initiated to prevent irradiation of the patient, until the discrepancy between the treatment plan and the actual setting of the device has been resolved so that medical errors are kept to a minimum "

Also this facility for automatic comparison of the treatment plan with the actual setting of the machine can according to a special embodiment of the invention consist of a programmed general purpose computer.

According to a development of the invention, a data output device is provided with which the operating personnel of the prescribed treatment plan and actual settings of the radiation device, so that the operator can easily find any discrepancies can see between these two.

According to a further development of the invention, the prescribed Settings for the radiation treatment device stored in a memory, for example a magnetic tape, a magnetic disk or a punched tape, and the device has facilities with which the prescribed Settings of the machine can be read from the memory

According to another development of the invention the prescribed settings of the device for the administration of a certain treatment by a handler

209824/0952

lungs memory read out and into the memory of the computer read in. The computer is programmed in such a way that the prescribed machine settings are read out from the memory to be compared with the actual settings of the device.

According to another development of the invention, simultaneous Adjustment movements of the frame and the treatment couch are provided, so that the set-up time for the device is considerable can be reduced.

According to a special embodiment of the invention are The lounger and the frame can be moved over interfering paths and the simultaneous movements of the frame and The couch is monitored in such a way that an impending collision between the couch and the frame is detected and a corresponding signal is generated.

Devices are preferably provided with which an impending collision between the frame and the Lying is detected, and the device is controlled so that an impending collision is avoided while it is ensured that the frame and the lounger are in move the desired setting positions.

The invention is to be explained in more detail with reference to the drawing became; show it*

1 shows a partially executed block diagram Scheme of an automated radiation treatment device with features of the invention;

FIG. 2 is a circuit diagram of a circuit for forming signals which indicate the settings of the various Specify the parameters of the radiation treatment device;

20982W0952

-. It /

Figures 3A to D show a program flow chart for a Computer that controls the setting and a collision between the frame and Avoid parts of the couch dee radiation treatment device according to the invention;

Fig. 4 that enclosed in Fig. 1 by the line 4-4 Part with dimensions; and

FIG. 5 shows a section along the line 5-5 in FIG.

Xn Fig. 1 is a computer-controlled radiation treatment device illustrated with features of the invention. The radiation device 1, for example a radiation treatment device CLZNAC (Registered Trade Mark) model 4 or 35 »like it is supplied by the applicant, or an automated Cobalt 60 radiation device THERATRON 80 from Atomic Energy of Canada Limited, Ottawa, Canada, has a couch 2 a table 3, which receives the patient to be treated. The couch 2 is around a vertical axis 4 with the help a turntable 5 to which the bed 2 is attached is · The couch has a lift 6 with which the couch can be moved in the vertical Z direction. Additionally vcist the couch is motorized drives with which the table 3 can be displaced in the lateral Y-direction and longitudinal-X-direction is. A control unit 10 is connected to the bed 2 with a suitable line to control the various parts to control the radiation device manually and an automatic control of the radiation device 1 by the computer enable·

A generally C-shaped frame 8 is 359 ° around a horizontal Axis 9 rotatable. The frame 6 is rotatable by a Stand 11 supported. A radiation source, for example a linear accelerator, that generates a high-energy electron beam that is directed against an X-ray target

209824/0952

-Y · ".

is _s delivers an X-ray beam from a collimator-. Head 12 goes out »Instead, in a cobalt device, the cobalt serves as the source for the radiation, and the cobalt is housed in the collimator head 12. The rays emerge from the radiation head 12 in a ray whose axis 13 intersects the frame axis of rotation 9 at a point designated as isocenter 14, through which the turntable axis 4 also runs.

The head 12 has two sets of movable beam limiter jaws, such as lead, which are movable to limit the length L and width T of the field of the beam as collimated by the beam limiter jaws. The source 12 is seated in a cone-shaped collimator housing 15. The source housing 15 can be rotated about the beam axis 13 together with the beam limiting jaws. The frame 8 has a radiation trap IG which is arranged along the beam axis 13 and contains a radiation absorbent material, for example lead, with which the beam is slowed down and absorbed.

A digital computer 18, for example a general-purpose digital computer model 620 / i from Varian Data Machine, is coupled to the radiation treatment device 1 via a control cable 19 and an interface 21 is "which contains the addresses" and arithmetic units. Sixteen channels of analog-to-digital converters 24 are provided to convert analog output signals derived from radiation treatment device 1 into digital form, which in turn are fed to central unit 23 to be used there and in memory 22. Eight channels of digital-to-analog converters 25 are provided in order to convert digital output signals from the central unit 23 into analog signals.

20 9824/095 2

are supplied to the radiation treatment device 1 via the interface 21. Measuring transducers and control lines are for the transmission of measured values and control functions of the radiation treatment device provided via the interface 21. A machine console 27 is connected to the radiation treatment device 1 and the computer 18 via the machine interface 21 coupled.

Bin 620 / i «Computer from Varian Data Machines is a system-oriented digital computer. It has a total storage capacity of 123CC words of 16 or £ 1 bits and is expandable with plug-in units. The memory is a magnetic core memory with 1.8 microseconds full cycle time and 700 nano seconds access time. The arithmetic is parallel, binary »fixed» two's complement «You hc.t seven addressing modes and over 100 standard instructions «in addition to the The standard equipment of the Varian 620 / i computer v / e is the computer 18 an expansion chassis 620 / i, two storage units. 620 / i, which allow an additional 8192 words, an additional package 62Q / i ~ 17, a punch tape reader 620 / i-51, a Data acquisition and control unit, and the machine interface 620 / i on.

The additional package 620 / 1-17 has hard-wired multiplication and division, additional addressing, real-time encoders, power failure restart and eight priority level interruptions. The addition of 620 / i-51 is a high-speed tape reader, which provides a fast means by which the memory can be loaded, if a program miB lost for some reason has been scrambled ODSR. It is a pure input device, holes are not possible. Sr reads at 300 characters per second · The data acquisition and control unit contains the following! 7 or 12 bits plus sign program-

209824/0962

measurable query and maintenance, 16 channels or multiplex analog-digital conversion 24, and the eight channels of 9 bits plus sign digital-to-analog converter 25 as well as 16 transducers and 8 control lines 26. In addition, the The data acquisition and control unit is the BCD (binary encrypted Decimal) registers and controls for * the BCD formation 'which is available from the straightening device ΐ.

A digital cassette tape unit 28, for example a COIHJCORDER, model 100 from Datatronlcs Ine · »Rochester« N * Y. is connected in a suitable i ^r else with the central unit 23, so that digital data stored in the associated the individual patient cassette in the CPU 23 and the memory can be read 22nd In addition, output signals are read back from the central unit 23 via the sand unit 28 into the patient cassette. A data viewing and input device 29, for example a screen keypad station model ALPHA. 103A from Beehive Medical Electronics, Inc., Salt Lake City, USA, is connected to the central unit 23 by a line 31 in order to output data read out from the memory 22 by the central unit 23 and to control certain operations of the radiation treatment device 1 via the computer 18 ·

The data station 29 forms the main input and output device : '' r the computer 18 and has an alphanumeric output on. A standard typewriter keypad is provided as well as a Viörwege position display control. In addition, there is a 28 cm screen with twenty lines and forty characters per line. Stetion 29 is for overwriting using the position indicator or a line erase or a screen erase. Ss is its own internal character generator

0982 4/0952

provided with 64 characters ASC II. A remote daughter vision device 32 is intended for separate observation of the data. A standard ASR 33 teleprinter unit is suitable Lines connected to the central unit 23 to provide for a written record and around to serve as a reserve input for the data station 29 and the paper tape reader of the computer 18.

In Fig. 2 one of the circuits is shown with which an analog position signal is generated that determines the position of one of the variable parameters of the radiation device 1, such as frame angle G, housing angle H, bed position in the directions X, Y and Z, etc. The Position signal circuit according to FIG. 2 has a potentiometer 34 of, for example, 10 k ohms, which is connected to the drive shaft 35 by a mechanical coupling 36. A drive shaft 34 generates the movement of the controlled parameter in such a way that a movement of the changed or controlled parameter extending over the full scale ensures that the full scale of +10 volts to -10 volts analog output voltage from tap 37 is taken from potentiometer 34 v / ird. -15 volts and +15 volts, respectively, are applied to the two ends of the potentiometer 34 via trimming potentiometers 38 and 39 'which are connected to the ends of the potentiometer 34. The trim potentiometers and 39 provide calibration of the range and endpoints for each position signal reading. The beam collimator jaws and position indicators use one turn potentiometers 34 that have a linearity of 0.25 % and a resolution of 0.095 % . For the other analog position readings, potentiometers 34 with ten turns, a linearity of 0.1 % and a resolution of 0.019 ^r /> are provided.

2Q9824 / Ü952

Each of the motorized control movements of the radiation device 1 is driven by a shunt DC motor 40, which is supplied with energy by a controller 41 made up of controlled silicon rectifiers. With the exception of the Frame rotation controls are each control open loop that provides a full output signal upon receipt of a 6 volt DC signal, with the output voltage goes down to Hull at 0.5 volts DC, so that there is a dead band of + 0.5 volts · Die Frame speed control has a closed loop, is speed controlled and provides output signal "full speed" due to an input signal of 12 volts DC voltage, again with a dead band of + 0.5 volts · The turntable drive is equipped with a brake that engages when the input voltage of the Engine control is zero. The longitudinal and lateral movement a the couch are equipped with switch-operated electrical couplings that connect the respective drives.

A control of every movement of the radiation treatment device 1 is obtained by direct digital control. The positions of each of the eight analog movements are interrogated by interrogating the output of each potentiometer 34 every 50 milliseconds, taking 10 microseconds for each interrogation. The removal is controlled by the central unit 23 and effected by the interface 21 and the position control circuits according to FIG. 2, which are coupled to the drive 35 for each of the driven elements of the radiation treatment device 1 their feedback can be changed from zero to maximum within 15 seconds. If 12 bits plus sign are assumed, the output signal of the analog-digital converter changes by a maximum of one last-digit bit in 3 »6 milliseconds, so that a maximum of 4 changes to the last-digit

209824/0952

Bit can be observed at every reading.

Each patient's records include a digit, al tape cassette. To treat a patient, his cassette is inserted into the tape unit 28 and a command from the input device 29 ensures that the tape is read into the central unit 23 and stored in the memory 22 of the computer 18. The information transmitted from the cassette to the memory 22 of the computer 18 contains the patient's identification number, his name, the diagnosis of his condition, the portal definition of eight separate radiation treatment portals, each with an identification number 1 to 8 and a definition of the sizes G, S _t X , Y, Z, H ₈ L ₉ T and the dose for each of the defined portals, whether the individual treatment also includes arch therapy, and, if this is the case, the frame viiikeX C for the beginning and end of the arch, and the radiation dose (rad ) per degree, as well as information regarding wedges, if they should be used and whether blocks should be used. Wedges are used to shape the intensity of the beam and blocks are used to protect certain parts of the treating patient from radiation from the beam. In addition, information read into the memory 22 from the patient cassette has a sequence as to how the portal deflnitions are to be administered, that is, an open treatment plan , the monitored cumulative dose per portal, and the total cumulative dose for the patient.

As soon as this information has been stored in the computer 18, the input device 29 is actuated in order to output the desired information from the memory 22 on the output of the station. On the basis of the corresponding command from the keypad of the station 29, the central unit 2.5 ensures that the next treatment to be carried out is output from the memory 22 on the display device 29. A certain

209824/0952

Radiation portal is, for example, on the alphanumeric display device through the prescribed setting points of the Defined sizes G, S, X, Y, Z, H, L, T etc. Compared to the prescribed fourth for these quantities, which define the treatment to be carried out, becomes the corresponding current one Position of each of the settings of the radiation treatment device c 1 output. Position values are taken from the output of the position circuits of the type shown in Fig. 2, after this via the analog-to-digital converter in the digital form has been converted and after it has been sent from the central unit 23 to the screen of the station 29 ■ have been. After the corresponding command button on the Control unit 10 has been pressed, the central unit 23 ensures that the actual position signal is monitored is and compared with the prescribed position signal to form calibration signals that are sent to the controls are supplied to ensure that the radiation treatment device 1 by the treatment plan to be carried out take up defined positions «

The permissible value ranges for the various adjustable parameters of the radiation treatment device 1 are stored in the core memory 22. In particular, the following permissible fourths are stored in the memory: ϊ frame angle GO-359 ° · rotary angle S -90 to + 90 °; Run of the couch in the X-direction -056 to +544 mm; Run the couch in the Z-direction -20 ζκα to +560 am; Radiation head viacol H -90 to + 90 °; blade L of the irradiated field in 60 approx. from the source 0 to + 320 mm; Width T of the irradiated field in 80 cm distance from the source 0 to + 320 ma. The computer memory also stores: A range of permissible radiation dose times from 0 to 9.9 minutes; Can range from 0 to 999 rad; permissible wedge numbers 0 to 7 »frame stop angle, between 1 and 359 ° for arch therapy, and rad pro

20982W09S2

BAD ORlQiNAt

Degrees for archery therapy between 0.50 and 5 »00.

An anti-collision program later in conjunction with Fig. 3 is stored in the memory 22 and the CPU checks according to this program continuously the possibility of a collision between the frame 8 and the couch 2. If an impending collision is determined, an anti-collision test routine is started executed to report the collision. The radiation device is prescribed according to the predetermined Positioned plan · The geometric setting points can be reached in less than 30 seconds, since all geometric movements of the beam device can be achieved at the same time.

When each of the geometric parameters reaches its set point, the value of the set point becomes displayed on the screen against the corresponding prescribed value of the treatment plan to be carried out. All setpoint values for sizes G, S, X, Y, Z, H, L and T are thus automatically reached and presented automatically. The planned values for dose, time, rad per degree, Stop angles, wedges and blocks are output, but this one Adjustments are made manually from the hashlnon console 27. Any of the manual settings of dar The machine console 27 has a BCD position signal generator of the usual construction, which is coupled in the usual way. When the manually adjustable parameters have been set, the corresponding position value is entered in the Computer 1C fed in and presented next to the planned value. Each wedge and block is electrically separated Connections are coded, and electrical connections are made to these coded connections in order to provide an input signal to the computer 18 in accordance with the specific, Feed in the wedge or block that has just been used. Wedge and

209824/0952

Block information is also fed to the computer and presented on issue 29.

The computer 18 is programmed so that the prescribed Value for all mentioned geometric and other device parameters are compared with the set point values, which have been achieved by each of the set parameters »If all these prescribed values are the set point values do not correspond, the computer 18 delivers a locking signal, which is led out via the interface 21 is that a relay 45 is actuated, which opens a circuit in the machine console 27 and excitation of the radiation "on" head 46 in the machine console 27 prevented so that the beam cannot be directed at the patient until all of the actual set point values for the variable parameters of the radiation device correspond to the prescribed fourth. This will make the The probability of an operating error is significantly reduced and also the possibility that the patient will a radiation dose is administered which is not required in the prescribed treatment plan tolerances in The mechanical adjustments can be built into the system to remove uncertainties about the location of the Compensate patient on the treatment table 2.

The radiation head 12 of the radiation treatment device 1 has a dosimeter with which the radiation dose is monitored that is actually administered to the patient · The output from the dosimeter is continuously nourishing the entire treatment is monitored by the computer 18. The measured radiation dose per treatment is stored in the memory 22 of the computer and output on the display device 29 * In addition, the computer updates the in memory 22 stored information regarding the treatment plan status of the patient concerned by the

209824/0952

2156535

Update portal status part of the treatment plan, to include the cumulative sum of the radiation dose administered by the particular Bortal being treated as well as the total dose given to the patient has been administered · The status information is also updated by the treatment that is stored in the hand » treatment sequence has just been administered and which numbered Next treatment to be administered.

The treatment plan portion of the information in memory 22 with the treatment plan of the patient is also updated by the computer in that a rake, for example an asterisk is inscribed under the number of the Bortal definition, which is just in the sequence of fortal numbers which defines the treatment plan sequence.

After the treatment is complete, a locking signal goes from the radiation device 1 to the computer 18. This locking signal prevents the computer from performing any function other than printing out the updated portal definition information for the portal just treated. The printout is made on the telex 33 <The printout shows the complete portal definition from the prescribed and existing positions of the elements etc. together with the current date, time, the cumulative dose for this portal and the total amount of the dose administered to the patient.

After the printout, the operator presses the command ElIDE Im Keypad so that the computer 18 receives the command that all updated treatment plan information, portal definition information etc. pertaining to that patient from memory 22 back into the individual's tape cassette To read out patients via the tape unit 28.

209824/0952 _ _

Any detail of the prescribed overall radiation treatment plan or any of the prescribed parameters individual portal descriptions can easily be changed during the treatment. The operation becomes a Button "editorial office" on the keypad 29 pressed and the corresponding change is keyed in. Two levels of editing options are provided. Certain major changes such as overall changes to the treatment plan, can only be initiated by monitoring personnel with a special access key, which is used to set up an interlocking circuit to be completed in an interface between the data station 29 and the central unit 23. ¥ enn der If the therapist wishes to have a periodic check-up before certain treatments can be administered to the patient, he can require the presence of surveillance personnel for a particular treatment by adding a legend in the overall treatment plan is written

Any new machine parameter planned for a change in a treatment plan or a portal definition becomes compared by the computer 16 with the respective permissible ranges for this parameter, which are stored in the memory 22 are. If the intended advantage of the parameter is within the permissible Area, the change is read in and the treatment plan or portal definition stored in memory 22 is edited in this way.

If the intended change to a parameter is not within the permissible range of values, the display device 29 an error message is output and the intended parameter change is not read.

The computer-aided beam device 1 also has the possibility of simulation. In simulation mode, this will be Radiation treatment device by hand from the control unit 10

209824/0952

controlled in such a way that the geometric machine parameters are positioned for a specific treatment to be carried out. The final settings of the device are made by the respective position output signals and definition parts a complete portal definition. With a corresponding command, the operation causes that the computer 18, the manually set device parameters are transferred to the memory 22 to define a portal to be incorporated into a treatment plan, that is to say in information stored in memory 22 for this patient is. This portal definition is then \ irirred by completes the operation and becomes part of the patient treatment plan, which is transferred to its cassette in the manner described above

At the beginning each position is read off with the desired one Setpoint compared, and a voltage is applied to the corresponding controller, increasing linearly to the final value Veise to get a "soft" acceleration and an excessive shock wave through upstream line disconnectors to prevent · The desired start periods are determined empirically, suitable values are, for example 500 milliseconds for the frame rotation, 200 milliseconds for a movement of the bed lift, and 100 milliseconds for the other movements.

jt

The anti-collision program is stored in the memory 22, and the central unit 23 continuously checks the possibility of a collision between the frame C and the bed 2 in a manner to be described in more detail. Each of StcuerunG full voltage is applied to either eino imminent collision is detected or the relevant moving element calibrated to the desired set point approaching · V. ^T hen Any desired set point is reached,

20982W0952

the corresponding control voltage is reduced linearly within a proportional band until the displayed position is within the tolerance band, which is usually 0.1 % of the final value, and then the control voltage is reduced to zero. Again, the values for the proportional and tolerance bands are determined empirically. When all movement at the respective set point has been completed, control returns to the output-input-output routines.

The anti-collision program checks all possible collision modes for the current combination of the parameters of the radiation treatment device. If security rooms around approaching elements are penetrated, all movements are grounded interrupted · The last step above the actual physical dimensions to define the security room was set to about 25 mm. If an impending collision has been discovered and the movements have been interrupted, the program ensures that the four main motion candidates for collisions, namely the Frame rotation, bed rotation, side adjustment of the bed and lifting of the bed, briefly, i.e. 5 seconds long to be moved towards their neutral position. Then this movement is interrupted and there is another attempt performed at the desired set points by making the various movements their Resume running towards the desired setpoints. If this new attempt is unsuccessful, everybody will Movement is interrupted and the sequence repeats a certain number of times, about five times. If after five attempts a collision is still imminent, all movements are permanently interrupted and an error message is displayed output on dsm display device 29.

2 0 9 U,! · '»/ D ΰ 5 2

In Figures 3A, 3B, 3C and 3D is a simplified A'blauiplan shown for the collision avoidance program, showing the types of possible collisions, how their probability is determined, and the consequences of bills that are carried out to the approaching of collisions.

In the program flow chart, the usual designations have been used to designate the functions. More precisely, a diamond-shaped box means a simple de-emptying function, a rectangular box means a calculation. The numbers in brackets assigned to each box indicate the algorithm used in the calculation and are repeated in the following table of algorithms. The flow chart is read from top to bottom and from left to right. The coat of arms-shaped blocks indicate that the sequence is to be continued on another sheet, and on this other sheet the circular block, which contains the same number as the coat-of-arms-shaped block, is entered. If the process branch ends with an arrow that leads to a circular block with a number, the program is continued at the same Βίε fct at a position higher on the sheet that is marked with a circular block that contains the same number , and an arrow entering this block. The block in the form of a trapezoid lying with the small side down indicates that a message is being output or also printed on the display device 29 according to the message indicated in the box.

The control algorithm for the automation of the StrahlUümndlungsgsrätes is üo si inconvenient, since <3 a fast, simultaneous I $ ßWfa £ Uiii; eight mechanical settings dv > irtrahlen »buhantJLLuügi.gfcrates to prescribed Linstellpimkton before« y.: - :! i -. i \\: α is that are in the treatment plan, ds7 ha SpoLoi: r tl «t. We have a potential collision .; ,: --i.vnc.ht

I ■■ "· j δ? - · ■ 'ü 0 B 2

BATH ORIGINAL

prevents, avoided if possible, and if otherwise unavoidable due to incorrect setting points, all movements are grounded stopped and an error message is output «Every movement is" started softly "one after the other to avoid overload to prevent the control circuits

For the purposes of the anti-collision program, the bed including a patient defined. It is believed, that the patient should have a space above the table measuring 45 to 7 cm wide, 203.2 cm long and 25 cm high, has flat ends and curved sides that go over tangentially ir. the side edge of the table 3 and with a yes radius of curvature from 40 cm to the top of the patientor.zo: ie curved are ο

The control algorithm is ^s eintet into four sections ILTI (1) the control logic tree, (2) collision test-sub-.Lnen, (3) Beve £ tmgssteuerung subroutine and (4) Kollisi.onüverin & idung subroutine.

Algor ithraen-Tab hurry (Dimensionless numbers are in ma)

(1.1.1) The main branch in logic occurs when the Patient bed aligned with the frame axis Is-; (Vinksl Si0.5 °). Venn that's the case, and the couch hell (Z) smaller or equal to 84 am is the most likely collision between the collimator housing and the edge of the bed plate, which can happen if it is

(Z + 1O) ² + [229 + IyJ] ² > Rp

where Y means the displacement of the couch! and R, the radius from the isocenter to the collimator housing in Hillimctei 10 is the thickness of the bed top and 229 is half that

209824/0952

BATH

Width of the bed. When a collision is impossible, wild the motion control subroutine (6.1.1) is called.

(1.3.1) If S * 0, but Z is between 84 and 278 mm the most likely collision one between the collimator housing and the edge of a bed rail that is possible, v / enni

(z + ei) ² + [213 + I υ I] ² >

If collision is impossible, the motion control subroutine (6.1.1) called. 61 is the thickness of the rail and table end, and 213 is half the distance between the outer edges of the rails.

(1.4.1) If a collision rail / collimator is possible, Z is greater than 242 mn and G is between 90 ° and 270 °, the possibility of a collision between the table rails and the radiation trap is checked:

(z + 6i) ² + [213 + | y |] ² > Rfo

where R ^ is the radius in mm from the isocenter to the ray trap is.

(2.1.2) Bed rail edge collimator housing ί

[(] YJ + 213) x | sec (s) I + 254 I tg (s) |) ² > R ² - (Z + 61) ²

(2.1.3) Edge of the bed plate collimator housing

[(JYj + 213) x | sec (s) [+ 254 | tg (s) |] ² > R ² - (Z ₊ 1O) ²

(2.1.4) Edge of the bed rail radiation trap:

[(JYj + 213) x (see (s) j + 470 J tg (s) | j ² > R ² - (Z + 61) ²

(2.1.5) Edge of the bed plate - radiation fall

[(| Y | + 229) x | sec (s) | + 470 | tg (s) (] ² > R ² - (Z ₊ 1O) ²

9824/0952

-

. _25th 2158S35

(2.1.6) Corner of the bed rail collimator housing:

[(| y | + 213) x I cos (s) | + X | sin (s)!] ² ^ ² - (Z +

(2.1.7) Corner of the couch plate collimator housing: ₂

[(I Yj + 229) xj cos (s) j + X | sin (sj] Vc ~ ^{(Z + 10} > ²

(2.2.2) Corner of the bed rail radiation trap:

[(I y | + 213) xj cos (s) | + x | sin (s) | J ² ₇ R ² - (2 + 61) ²

(2.2.3) Corner of the bed plate radiation trap:

[(| Y | + 229) x | cos (s) | + X | sin (s ^ R ² - (Z- 1O) ²

(2.3.1) Radiation trap side of the liftst O -Δ) - 260 | sec (s) | | csc (G)] - R _fe1 (1 + Δ)

[itg (s) (cos (A) + (cos (G) I sin (A)] | esc (G) | <0

where mean:

A β arc tg £ | ctg (s) | Icos (G) J], Δ-a cushion factor of 25 mm; 280 is half the width of the lift and R ^ ₁ is the radius

the ray trap in am if S 7 17 °; and

-585 | sin

where mean:

- B β arc tg [tg (A) | cos (G) I] and
. " Arc cos L585 / cos (s) / 1

if 6 ° <s ^

(2.3 * 2) Radiation trap lift end:

R _e | csc (s) | - 794 | sin (G) | -τ ^ ₂ (1 + £) [cos (A) | ctg (s) I sin (A) I cos (G) | <0

where mean:

A * arc tgptg (s) | jcos (G) JJ; R _ß the radius from the turntable axis to the end of the lift, and R ^ ₂ the radius from the beam axis 13 to the far side of the beam trap.

209824/0952 .26 -

(2.4.1) If G is between 270 ° and 90 °, collimator housing couch rail t

| | Z + 61

where R _{c <} | is the radius of the collimator housing.

(2.4.2) Radiation trap patient:

R _b1 (1 + A) | sin (G) I - ^ (1 - &) | cos (G) |> Z - 250

where 250 is the assumed strength of the patient.

(2 * 4.3) Vexai G is between 90 ° and 270 °, collimator housing and patient:

R _c1 (1 +4) | sin (G) | + R _c (1 -A) | cos (G) |> 2 - 250

(2.4.4) Radiation trap couch rail:

(1 -Δ) | cos (G) I - R _b1 (1 + A) | ßia (0) |> Z + 61

(3.2.1) Frame corner-lift side

75O | sin (G) I- 407 | cos (G) | | cos (s) | - 318 | sin (ε) (-

(3.2.2) Frame corner-lifting end

[514 | sec (s) | - 318j | ctg (b) \ - 985 | sin - 407 | cos (G) | C0

(4.2.1) Collimator housing lift corner:

A collision is to be feared * if S> 36 ° and G between 80 and 90 ° or S <-36 ° and G between 270 ° and 280 °. If this test is an upcoming one Indicates collision and the arc marking is not set is »the collision avoidance subroutine is called. Venn the bow marking is set and a collision is indicated, the program displays an error message. If no collision is possible, the population control subroutine is called.

209824/0952

- 27 -

(5.1.1) Radiation trap-Schwinmtisschkante g [(IyI + 280) j sec (β) | + 470Jtg (s) |] ² > n | - (Z + 21O) ²

(5.1.2) Radiation trap on the swimming table side R _b (1 -Δ) - (280 + JYj) {sec (») | jcsc (G) | R _b1 (1 + Δ) | tg (s) | cos (A) + [cos (G) jsin (A) jcsc (G) | <

wherein
A m arc tg (ctg (s) | icos (s) |

(6.1.1) Motion Control Subroutine

Each of the eight mechanical positions is monitored and compared to the corresponding setting point. «Each movement is assigned a tolerance band and a proportional control band. For each movement, voltage is applied in order to move this movement towards the adjustment point if the deviation between the adjustment point and the measured position exceeds the tolerance band. If no control voltage is currently applied, a temporal voltage increase to the maximum is applied in order to obtain a "soft * E; 3eM, @ isnigung" so that the peak current is reduced to the value © inaerMXb of the limits of the control circuit The set point is continuously monitored, and if its movement leads into the proportional control band, the control voltage is reduced linearly to 0 within the tolerance band.

(7.1.1) The collision avoidance subroutine initially stops all mechanical movements and resets a counter. For a certain time interval the turntable, the frame and the X and Z movements of the couch are driven back to their respective zero positions. Ee will then try another attempt to get the desired setting. If according to a predetermined attempts to continue indicating an impending collision will stop all movement and it will «An error message issued.

20982 / - »/ 0952

Claims (13)

τι 18 Claims ί 1 ·) Radiation device with an adjustable bed and a Holder for the radiation source set up for rotary movements and position sensors for the respective position of the bed and the holder as well as a device for the formation of the Target position of the bed and the corresponding signals, characterized in that comparison devices are provided in which the signals from the Position sensors and the signals are compared according to the corresponding target position and with which control signals are generated and that the drives for the adjustment movements of the bed or the rotary movements of the holder are all can be controlled simultaneously with these control signals ο 2. Apparatus according to claim 1, wherein a collision of the couch is possible with the radiation source in the course of the movements, characterized in that monitoring devices are intended for the simultaneous movements of the bed and the radiation source in the event of impending Provide a warning signal for a collision 3. Device according to claim 2, characterized in that that responsive to the warning signal, a collision preventing controls provided for the motion drives are· 4. Apparatus according to claim 3 »characterized in that that the controls have stop devices for the drives and feedback controls that have a return movement of the drives towards their neutral position ? (j Q η? /, / η 9 ' ι OWGJNAL INSPECTED control given time, and an automatic shutdown with which the drives return to their original operating state be switched back 5. Device according to one of claims 1 to 4, characterized that a locking device is connected to all comparison devices, which a Blocking signal delivers as long as one of the comparison devices outputs a control signal and that the irradiation device has a lock that prevents irradiation as long as a lock signal is present 6. Device according to one of claims 1 to 5, characterized in that a memory for irradiation data is provided and a feedback device of the device is connected to this memory, with which the memory data are supplemented by the irradiation that has taken place. 7. Device according to claim 6, characterized in that that the feedback device has a dosimeter which is arranged in the beam from the radiation source " 8. Apparatus according to claim 6 or 7 _»v characterized in that the Speichor contains data for permissible parameter value Berelche and comparison means are provided with which the target irradiation data compared with the data of permissible parameter value ranges v / earth and to which a lock connected for irradiation 1st. 9. Device according to one of claims 1 to 6, characterized in that the comparison devices, Monitoring devices, controls, locking devices, Locks and / or memories are part of a freely programmable computer 20982A / 0952 10. Apparatus according to claim 9 »characterized in that a screen dialog unit is connected to the computer connected 1st. 11. Apparatus according to claim 9 or 10, characterized in that a teleprinter as a dialog station is connected to the computer. 12. Apparatus according to claim 9 · 10 or 11, characterized in that a memory separate from the computer intended for the target position of the couch and the holder as well as other irradiation data for each individual patient is, a reading station with which the content of this memory in the memory of the computer ο island β can be sen, and an output with which updated data can be read from the computer into the separate memory. 13. Apparatus according to claim 12, characterized in that the separate memory comprises a storage tape. 209824/0952 Blank page