US 2748292 A
Description (OCR text may contain errors)
May 29, 1956 Filed May 14, 1953 J. WORDEN 2,748,292
SIMPLIFIED X-RAY APPARATUS 2 Sheets-Sheet 1 May 29, 1956 Filed May 14, 1953 2 Sheets-Sheet 2 f SIMPLIFIED 'IOOMqmcrmmuc PART DIST. BUCKY TIME PART DIST. BUCKY TIME ch": 11 Heart PA 72" No 1/20 Skull AP 30" Yes a 4 Chest 81 Heart OBL 72" No 1/10 Sku1l LAT 30" Yes 3/ 4 Chest I: Heart LAT 72" No 1/10 Cervical AP 30" Yes 1/ Z Stomach PA 30" Yes 3/10 Cervical LAT 30" Yes 1 z Colon PA 30-- Y" 3/10 Cervical LAT 72" No 1/ z Esophagus OBI. 30" No 1/10 Dorsal AP 30" Yes 3/ 4 Etophagua OBL 30-- Yes 3/10 001-511 0131.. 30" Yes 1/ z Kidney AP 30 Yen 4/10 Dorsal LAT :0" Yes 1/ 2 Urinary Tract AP 30" Yes 4/10 Lumbar AP 39'' Yes 3/ 4 Urinary Bladder AP 30" Yes 4/10 Lumbar LAT 30" Yes 1 Gall Bladder PA 30-- Yes 2/10 1111 AD 30" Yes 1/10 Ribl no 90'' Yes 3/10 Pelvis AP 30" Yes 3/ 4 Extremities lfz p il N 3 0 /1o Foetus AP-PA 30" Yes 1/2 2 to 5 cm. Holder Foetus LAT 30" Yes 3/ 4 Extremitiee Exposure Hip 101111, AP 30'- Yes 1/ z 5 to 10 No 4/10 Hip Joints 05L 30" Yes 1/ Z Extremities Screens 51 B AP 36" Yes 1/2 2 to 5 cm. gassette] 36" l/l0 Thigh LAT 36" Yes 1/ Z Excremities Screens L Shoulder AP 36" Yes 4/10 6 m 9 cm. Eanefle] l/lo Sinus ALL 30" I No 2/10 Extremities Screens & 36" Sinus ALL 30 Yes 1/ Z 10 to 15 cm. Cassette Yes 3/10 Cast Work...Add 5 cm. to thickness measurement Based on Par-Speed Screens INVENTOR. e aae oiqafwo y-dsza United States Patent O 2,748,292 SIMPLIFIED X-RAY APPARATUS Jesse Loyal Worden, Chicago, Ill., assignor to Continental X-Ray Corporation, Chicago, Ill.
Application May 14, 1953, Serial No. 355,145
6 Claims. (Cl. 250-100) This invention relates generally to an X-ray system or apparatus and more particularly is concerned with an X-ray apparatus which is fool-proof and extremely simple to operate properly without danger either to the technician or to the patient.
The apparatus of the invention is a departure from the conventional X-ray apparatus in that a great many disadvantages of prior equipments have been overcome in a relatively small and inexpensive device. It comprises a combination of features the association of which give rise to the advantages.
The apparatus of the invention is advantageous especially in the fact that as a result of the construction, the output of the X-ray tube is always fixed at a predetermined value of current. The practical embodiment of the invention is constructed for an output of 100 milliamperes. The focal spot of the X-ray tube is constant; there is no need to calculate anything about kilovoltage or milliamperes; there is no need to calibrate the equipment; in fact there is nothing that need be done which cannot be accomplished by anyone of just ordinary intelligence. The result is that training for operating this equipment is a minimum. All that the operator does is to adjust the kilovolt output by a simple control to the proper value for the thickness of the part of the body to be X-rayed. The meter is calibrated directly in centimeters of thickness. The operator then chooses the proper time for the particular part of the body from a simple chart, sets that time in the timer, and throws a switch which will expose the said part. This is in great contrast to the complicated procedure which must be followed in using ordinary X-ray equipment.
It is therefore the principal object of the invention to provide an X-ray apparatus which eliminates a great many complications prevalent in ordinary apparatus; which provides fixed current output of the X-ray tube; which may be operated simply and effectively with a minimum of adjustments.
An important object of the invention is to provide a device which is extremely economical, not only to produce but also to operate. In connection with this object, the component parts of the apparatus are more economical, the time required to set up the apparatus for use is very much less than on previous machines, the power line requirements are less than on other apparatus of the same type, the X-ray radiographs are of high detail and contrast.
Many other objects will be come apparent as a description of the invention proceeds, from an inspection of which advantages and features not described will be apparent. I have illustrated a preferred embodiment of the invention in the drawings in which:
Fig. 1 is a perspective view of the control cabinet of the apparatus embodying the invention.
,Fig. 2 is a circuit diagram of the basic parts of the apparatus.
Fig. 3 is a plan view of the technique chart used with the apparatus.
2,748,292 Patented May 29, 1956 Fig. 4 is a plan view of the simple meter used in connection with the chart.
The invention herein comprises a combination of features which makes possible the extremely simplified technique of the apparatus. These features are a result of the use of certain hereinafter described structural parts, each of which contributes to the whole to produce the desired results.
In Fig. 1, there is shown the console or cabinet 10 of apparatus embodying the invention, the X-ray tube, the table, connecting cables, and the like not being illustrated in this figure. In order to explain the use of the various meters and controls, the technique practiced will be described prior to continuing with the explanation of the features of construction making the same possible.
In the top panel 11 of the console 10 there are shown two meters and a technique chart. On the left there is provided the meter 12, same being a voltmeter. This voltmeter has been pre-calibrated so that it measures the primary voltage of the principal transformer of the equipment in terms of the peak kilovoltage applied to the X-ray tube. Since penetration of the X-rays is a function of the peak kilovoltage applied to the X-ray tube, the meter may be calibrated also in centimeter thickness of the part of the body to be X-rayed, taking into account the output of the tube. Since the output of the tube is constant, the only variable to consider in the exposure is the thickness of the part of the body. The face of the meter 12 is illustrated in Fig. 4. It will be noted that the needle 13 plays over a scale the upper part 14 of which is marked off from zero to 30, signifying centimeter thickness of the part of the body being radiographed, and the bottom part 15 of which is marked off from 40 to 100, reading peak kilovolts applied to the X-ray tube.
The right hand meter 16 is a simple milliameter which has two ranges in the embodiment illustrated. One range is zero to milliamperes, which is used when the X-ray equipment is being operated for making radiographs, and the other range is for use in practising other techniques with the apparatus. The latter range is not of concern to this invention, and in fact, the 100 milliampere range is used only to assure that the apparatus is working properly, since the needle will be on 100 milliamperes during the entire time that the apparatus is being'used, the relations for calibrating the meter 12 being based upon this presupposition. The push-buttons 17 and 18 on the switch plate 19 of the lower panel 20 control meter range.
In the center of the upper panel 11 is a technique chart 21, preferably illuminated from its rear. This chart is shown enlarged in Fig. 3 and will be explained shortly.
On the central panel 22 there are provided two knobs 23 and 24, the left hand knob 23 being for adjusting the kilovoltage of the apparatus to correspond to the proper thickness of part of the body being radiographed, and the right hand knob adjusts the milliamperage output of the X-ray tube, but only when the meter 16 is being used on its 30 milliampere scale. For the 100 milliampere scale the needle will remain at 100 milliamperes during use.
The bottom panel 20 has an integrating or cumulative timer control 25 for use in connection with fluoriscopy, a central switch panel 19, and an electronic timer control 26 for use in connection with radiography. The main switch is indicated at 27, a bucky diaphragm switch at 28, and a light switch at 29. Not illustrated is a plug-in receptacle for a hand-held switch connected by a cable to close the circuit when it is desired to expose film. This is a simple arrangement in common use in practically all X-ray equipment.
The apparatus is used in the following manner; presuming that the equipment is properly adjusted and properly warmed up, and the patient is placed upon the table with the particular part of the body over the radio graphic plate, first the proper height of the tube over the filmisadjusted. Sincethetable andtube adjusting means form no part of the invention but may be of any type, these are not illustrated. Furthermore, since the equipment is admirably. suited for use in industrialapplications,
the tube may not be used with a table, but may be secured.
with brackets, etc. to a metal member or the like. Continuing with the explanation of the manner of use in obtaining a radiograph of a'patient, suppose that a lateral X-ray of the skull is to be taken. The adjustment of thirty inches as shown in the technique chart is made to raise the tube the proper height above the film. The technique chart requires the use of the bucky diaphragm, and hence the switch 28is thrown to on position. Let us say that the thickness or. the skull being X-rayed is measured as 18 centimeters. The knob 23 is. turned until the needle 13 reaches, 18 on scale 14. This signifies a kilovoltage of 72 will be applied to the tube. According to the technique chart, the time of exposure is three quarters second. This value is set into the electronic timer by the knob 24. Now, the operator merely closes his hand held switch, and the film is exposed at 100 milliamperes output of the X-ray tube.
Slight variations of technique are required under varying circumstances, but obviously the basic steps are the same. The thickness of the part of the body is set into the meter 12, the time is set into the electronic timer, and the film exposed.
The circuit of the apparatus is shown in Fig. 1. The line 30 is connected across an auto-transformer 31 through ganged switches. These switches are operated by the toggle 27 appearing on the plate 19. The output of the auto-transformer appears from the lead 32 to the lead 33 and is applied to the primary 34 of the high voltage transformer 35. The voltage across leads 32 and 33 is varied by means of a brush which wipes exposed turns of the auto-transformer. The movement is controlled by the knob 23 and hence the brush connection is designated by this character. The meter 12 is also connected across the output of the'autotransformer. The high voltage transformer 35 has two secondaries 37 and 38 each of which is connected across a four diode bridge rectifier 39 and 40 respectively. The right hand juncture 42 of the bridge 39 is connected to the cathode or electron gun 43 of the X-ray tube 44-, while the right hand terminal 45 of the bridge 44 is connected to the target or anode 46 of the tube 44. The tube 44'is of the rotating anode type, as indicated by the motor 47 connected to a source of electrical power 48 for rotating the anode. The left hand terminals 49 and 50 of the bridges are connected together through an amrneter, the same amineter 16 is illustrated in Fig. l, and also to ground. Thus the amrneter 16 is at very low'poter'itial','need not be insulated, and is not a dangerous portion of the apparatus.
This is full wave rectification which'enables the meter 16 to be at ground potential. In additionfconsiderable savings are effected because the kind of vacuum tube diodes required for an'eight tube arrangement are of considerable lesser voltage rating than in the event a four tube arrangement were utilized. This latter system is in known use but is inferior to the circuit shown.
The use of a full wave rectifier prevents high inverse voltages and currents from being produced and hence effects great savings in power requirements. It also'enables higher powers to be used without danger to equipment or to the operator. It has been found that none of the so-called 100 milliampere' 100 peak kilovolt equipments heretofore known operate at their full rated capacity because of the likelihood of damage to equipment, tubes and cables. With the apparatus of the invention, it"will be noted that 'when operating with parts of the body through thicknesses of around thirty centimeters, which is most usual, the apparatus is operating at full capacity.
The use of a rotating anode tube also contributes to the ease of technique. In the first place, all of the advantages of the rotating anode tube are achieved, and in the second place, the use in the invention, enables the simplified procedure to be attained. There is no need to adjust focal spot, and in the case of the rotating anode the spot is exceedingly small giving great detail and sharp contrast. The tube used in the commercial embodiment has a focal spot of 1.5 mm. The tube lasts longer and can be exposed longer without damage thus increasing the usefulness of the tube and enabling the apparatus to be used at high powers.
In all small X-ray equipments heretofore used the voltage applied to the tube was a higher voltage A. C. potential, it being left to the X ray tube itself to do the rectifying. In the present apparatus, the 'full wave rectifier eliminates the strain on the tube, the dangerous inverse voltages, and still does not increase the cost thereof to any substantial extent because of the elimination of other controls and apparatus required in said prior devices.
Since the equipment is constructed to enable the use of maximum rated peak kilovoltage without danger because of the rotating anode tube and the full wave rectification the time in which an exposure can be made is reduced from that required in other equipments of the same rating and even of greater power. For example, an exposure of 100 milliamperes at 100 kvp. is equal in value to 200 ma. at kvp. The tube limitations at the latter conditions however, allow exposure of only one and one-half seconds, while the former conditions readily attainable with apparatus permit an exposure of over 14 seconds without damage to the tube. In both cases it is presumed that other conditions are equal-that the focal spot is the same.
Because of this the time of exposure may be decreased, using higher kvp. on the tube.
It is believed that the invention should be fully understood and appreciated without further explanation and it is desired to point out that variations are possible without departing from the spirit orscope of the invention as defined in the appended claims.
1. A simple-operating X-ray equipment which is adapted to operate from a single-phase A. C. line of relatively low voltage and at relatively low load conditions, which comprises an X-ray tube of the type providing a constant focal spot for all conditions of radiographic use, a full Wave rectifier directly connected across'the tube and providing constant current to the tube under all conditions of radiographic use, a high voltage transformer connected tothe line and having its output connected to the rectifier, means for varying the primary voltage of the transformer, a voltmeter connected for reading the said primary voltage andsaid meter being calibrated to read'directly thickness of the part being X-rayedas a function of peak kilovoltage applied to the tube at the said constant current for proper exposure of said part, and a timing device connected to close the circuit of the X-ray tube for 'a predetermined time.
2. All equipment as described in claim 1 in which the rectifier comprises a pair of four tube'bridge-connected diode arrangements, the high voltage transformer has a pair of secondaries, each secondary being connected across the respective bridge arrangements, each arrangement having one juncture of each at common potential and the tube being connected across another juncture of each arrangement.
3. A simple-operating X-ray apparatus comprising a single-phase A. C. source'of relatively low voltage, said apparatus adapted to operate at relatively low load conditions, an X-ray tube of the rotating anode type, a fullwave rectifier unit directly conne cted across the tube and providing constant current to 'said t'ubeunder all load conditions, a high voltage transformer connected across the line and having its output conne'cted'tothe rectifier,
means for varying the primary voltage of the transformer, a meter connected for reading the said primary voltage and said meter being calibrated to read thickness of the part being X-rayed as a function of peak kilovoltage applied to the tube at the said constant current for proper exposure of said part, a timing device connected to close the circuit of the X-ray tube for a predetermined time, said rectifier comprising a pair of four tube bridge-connected diode arrangements, the high voltage transformer having a pair of secondary windings each connected across one of the four tube bridge arrangements, each arrangement having one juncture of each at substantially the same potential and the tube being connected across another juncture of each arrangement, there being an ammeter connected between said junctures having substantially the same potential, one of said last mentioned junctures being grounded.
4. An X-ray equipment comprising, a single phase relatively low voltage source of A. C., high voltage transformer means having primary winding means connected across the source, a pair of secondaries insulated one from the other and from ground, a pair of four branch rectifying bridges with a rectifier device in each branch, each secondary being connected across one of said bridges, an X-ray tube having anode and cathode, each bridge having a positive and a negative terminal, a current indicating device, the positive terminal of the first of said bridges connected to the anode of said X-ray tube, the negative terminal of said first bridge being connected to said current indicating device and being substantially at ground potential, the negative terminal of the second of the said bridges being connected to the cathode of the X-ray tube and having its positive terminal connected to said current indicating device.
' X-ray tube having a fixed focal spot, means providing a fixed predetermined current flow in said tube under all conditions of radiographic use, a rectifier providing direct current for said tube, a source of A. C. voltage connected to said rectifier, means for varying the voltage of said A. C. source, and a voltmeter connected across said source and calibrated to read directly the thickness of a part being radiographed as a function of the source voltage for said particular value of current flow.
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