US2900542A - X-ray apparatus - Google Patents

Description

Aug. 18, 1959 H. B .'MCEUEN 2,900542 X-I-RAY APPARATUS v F'iied Sept. 22. 1954 3 SheetS-Sheet 1 FIG'J.

. INVENTOR HARRY B. IWEUE/V ATTORNEYS Aug. 18, 1959 H. B. MCEUE'N X-RAY APPARA'I'US 3 Sheets-Sheet 2 Filed Seit. 2'2 1954 v FIG.3.

INVENTR HARRY B. IWEl/EA/ ATTORNEYS H. B. MEUEN X-RAY APPARATUS Aug. 18, 1959 s Sheets-Sheei 3 Filed Sept. 22, 1954 im ENTOR VNN ATTORNEY X-RAY APPARATUS Hau-y B. McEuen, Jacksonville, Fln.

Application September 22, 1954, Serial N0. 457,629

6 Claims. (C1. 313-56) This invention relates to improvements in X-ray apparatus and more paxticularly to a new type X-r-ay generator or tube and attendant circuitry and control apparatus, the capacity and output of which is at least tenfold that of the present day Standards. This marked increase in the output of X-rays Will enable the use cf denser filters or an increased thickness in present filters, and it will also enable the radiologist to increase the distance between the anode and the patients skin from the present day standard distance of twenty inches to as xmuch as six feet without increasing the time of treatment. This will increase the depth dose markedly in compari- :son to the surface dose of present day techniques, a fac- .101 which is very desirable in the treatment of deepxseated cancer. The increase in output is accomplished by nsing several anode ta.rget or focal areas, each of Which generates X-rays upon electron impingement and radiates said X-rays utwardly in a crossfire manner.

Althoughthis invention is particularly useful in X-ray therapy and is described in connection therewith, it is not restricted thereto, but is intended to apply to X-ray apparatus of any type whenever the invention as set forth herein may be utilized.

The desirability of crossfire radiation is based upon the theory that radiation from a single point when used in cancer treatment misses s0me of the submolecular atomic structures in cancer cells, whereas numerous X-ray groups originating from slightly different locations present a Iadiation which traverses all minute sections of the tissue being treated With a crossfire dose of X-rays throughont .the depth penetrted by these rays.

During treatment of a patient it is, of cour-se, essential .that all X-rays emerging from their respective target areas =be equal in quantity and intensity in order to prevent burning cf tissue by some X-rays Whil others insuf- 1ficiently accomplish their purpose.

Therefore, it i=s the pn'mary object of this invention fito provide an X-ray generator which Will supply homogeneous crossfiring X-rays from a plurality of anode target areas, there being an equal number of rays emitted .from each target area with all rays having the same force cf enetration or intensity.

A further object is the provision of a cathodic filament Ffor each of a plurality of target areas and means f01 producing equal electron flows therefrom and onto the .associated target area.

Still a further object is the rovision of an evacuated, :substantially all-metal X-ray tube having a filter directly :attached thereto, thereby avoiding the passage of X- :rays through insulative oil or glass and, consequently, j pr'eventing uneven filtration.

Another object is the provision of means for cooling ithe metallic tube and anode without danger of the operator Ibeing shocked by the operating potentials of the tube.

Yet another object is the provision of means to insulate the high potential measuxing and carrying means ater1t O in a shock-proof manner so that the measuring means can be easily read.

Still other objects of this invention will become obvious to those skilled in the art by reference to the following description of exemplary embodiments of the apparatus and the appended claims. The vaxious features cf the exemplary embodirnents may be best understood with reference to the accompanying drawings where- Figure 1 is a side elevational fragmentary longitudinal sectional view of an X-ray tube constructed in accordance with the invention;

Figure 2 is a sectional view of the tube in Figure 1 on line 22;

Figure 3 is a fragmentary sectional view of the tube and anode of Figure 1 taken approximately 011 the line 3-3;

Figure 4 is a face view of a cathode for use in an X- ray tube such as shown in Figure 1;

Figures 5 and 6 am sectional views of the cathode shown in Figure 4 011 lines 55 and 66 respectively; and

Figure 7 is a diagrammatic and schematic showing of X-ray apparatus illustrative of this invention.

Figure 1 illustrates the tube proper without any supporting mount being shown. The main body or Wall 10 of the tube is cylindrical and is composed of metal, preferably copper, the thickness of which may be approximately 5 mm.

At both ends 0f the Wall 10 is a joint 12 which is silver soldered or otherwise suitably connected to a metallic throat-like collar 13 narrowing to a hollow cylindrical neck 14 of the tube. The collar 13 may also be made of copper 01 a similar metal which can be spun to shape. Attached to each metallic neck 14 is a cap 16 which is preferably, but not necessarily, glass and is joined by an appropriate seal-off 18. If the cap 16 is glass, the seal-ofi 18 may be, for example, a chrome-iron ring fused to the neck 14 and the cap- 16. The cap 16 has a reentrant portion extending inwardly of the tube ends form ing a hollow protrusion or cathode st'em 20, at the inward end of which is a seal-off 22 ar0und the several filament wires 24. A cathode 26 having a metallic supporting neck 28 is fitted over the cathode stem 20 during assembly and held thereon by a metallic clamp 30.

The anode 32 for the X-ray tube is located near the longitudinal center thereof and extends both inwardly and outwardly of the main Wall 10. The anode is silver soldered or otherwise suitably mechanically and electrically connected to the wall 10 at the shoulders 34 on the anode. The upper portion 36 of the anode may be of any shape, but is preferably square as shown in Figure 3, the sides of Which are approximately four inches in length. At its =lower portion 38 two sides of the anode': are directed inwardly at an angle of approximately 45 to each other forming a V-shaped lower portion. 011 opposite sides of the V there are located, respectively, the anode faces 40 and 42, each face having thereon five tungsten target or focal areas 44 which may be more readily seen in Figure 3. Bach target area 44 is sep- -arated from its adjacent target area approximately onethe opposite side of the anode.

dissipation of heat. The anode 32 is further cooled by circulation cf fluid, preferably water through the inside of the anode and around the fins. The water enters through a flnid carrying conductor or pipe 48 connected to the upper and outside ortion of theanode at an opening 50 in one side wallof the anode and leave'zs -the anode throngh pipe 52 similarly connecte'd to Upon entering the anode the cooling flnid is deilected downwardly by a barrier 54 attachedto the top end of the anode. A flexible hose (not shown) 'mayrbe attached to each pipe end 56 so that the pipes '48 and 52 may be suitably connected, respectively,to a suitable sou.rce of water supplyand a disposal system.

Since 'the 'anode generates an enormous amount of heatpart of which is transmitted 10 the metallie tube Wall, the wall10 of the tube should be cooled also. This water ;is accornplished as shown in Figure 1 by adding an annu- "lar'jacket'58, of cpper or sim'ilar material, around the cer'1tral portion o'f the Wall so as to form a channel 60 for flow therewithin of a cooling fluid which is again preferably water. The jacket 58 rnay be silver soldered or otherwise suitably connected to the wall 10 at each outer 'end of the channel 60 and around the anode 32 and the filter 70. The channel has two inlets 62 and 64 and twooutlets 66 and 68 for purposes of better circulation 'of the' fluid through the whole channel; 110W- ever, it will be nnderstood -that only one inlet and one ou'tlet may be used *since the channels 60 on either side ofthe anocle as shown in Figure 1 communicate fully with each other in a direotion longitudinally of the tube except for the area immediately surrounding the anode at shoulders 34-and the area immediately surrounding the filter 70. The use of wateras the cooling fiuid in the -channel 60 and within the anode 32 provides direct coolsnugly fitted around tube wall 10 and attached thereto;

each ring may be attached to a supporting stand and will permit a rotatable mounting thereon. The rings 72 also form a support for the water pipes 48 and 52 thereby taking 211 the stress 01T the anode.

In order to allow the X-rays generated at the target areas 46 t0 be ntilized, there is provided a window area 74 in the Wall 10 of the -tube. A filter 70 of beryllium or other suitable material is permanently silver soldered or otherwise suitably attached to the Wall 10 and projects outwardly Through the window area 74. It should be -noted at this point that the X-ray tube is highly side atmosphere. The filter being perrnanently attached and having a thickness predeterrnined by the desired 'filtration Will provide a constant filtering effect upon the X-rays, there being no oil or glass ihrough which the X-rays need to Pass.

At each end of the tube there is a tubular metallic sleeve 76, preferably steel, fitted snugly over The tube Wall 10 and attached to rings 72 by bolts 78 disposed throu=gh an annular flange 79 integral With sleeve 76. A closure plate 80 of steel or sirnilar material covers the opposite open end of the sleeve 76 and is attached by bolts82 spaced around the periphery of plate 80 to another annular flange- 84 integral -with sleeve 76. Oiltightgaskets (not shown) may be necessary between the sleeves 76 and the rings 72 and also between The sleeves and closure plates80.

. All exposed portions of thesleeves 76, plates 80, tube wall 10, jacket 58, anode top 86, and the Wall pipes 48 and 52 near the anode are covered with a protective thickness of lead 88 10 stop any extraneous and undesired radiation of X-rays. The exposed sides of the anode may be lead covered; however, the thickness of the anode Walls is usually sufiicient 'to absorb undesirable radiations.

Near the outside ends of each sleeve 76 there is provided an opening-89 for the insertion of a flexible cable 90 carrying filament energizing wires With a high tension current thereon. The flexible cable 90 passes through opening 89 With an insulator 92, which is secured to slee've 76 by a packing mit 94, and further extends to an electrical couplingadapter 96 at the two cathode ends 0f the tube. The coupling adapter 96 has a male and female section, one of which is attached to the cable 90 and the other of which is permanently connected to the glass cap 16. The incoming cable 90 carries five pairs cf wires (plus a single cathode biasing wire if desired) and each Wire connects to a separate terminal Within adapter 96 for further connection by wires 24 passing through cathode stem 20 and neck 28 to the individual filarnents 98 in cathode 26. Since the cable 90 and the adapter 96 carry a high potential, the space 100, defined by sleeves '76, plates and the ends of the tube, is filled With an insulating fluid, such as oil. Therefore, the gaskets, mentioned above in connecl:ion with the bolting of sleeves 76 to rings 72 and the closure plates 80, may Wall be necessary.

Bach pairl02 0f wires from the cable is connected to a separate filament as shown for one of the filan1ents 98 in Figures l and 6 and for all filarnents in Figure 5. If it is necessary to use cathode biasing, another wire 104 carried in cable 90 is brought through the cathode stern 20 and neck 28 to the cathode structure 108 andattached therc'zto by a screw 106 (Figures 1 and 5). Referring now to the housing for the filaments or the cathode structure 108 as shown in Figures 4, 5 and 6, it will be note'd that the structure cornprises five focusing cups 110 integrally or separately constructed and an equal nurnber of filament holders 112, each holder providing a solid floor section for the cup 110. The filarnent holders or floor sections 112 are connected to the bottorn of the cups by screws 114, the aperture through a floor section 110 for a screw 114 being a slot (not shown) providing for sidewise adjustability of the filarnent. 'Ihns,

a technician will be able to assemble the entire filament assembly to the closest er most accurate dimensions necessary. The transverse cross section of a filarnent holder forme an inverted 'T, the base 116 of which completely Covers the aperture through the bottom of a focusing cup portion 118 (Figure 6) of a filament holder 112, there are supporting members 120 for securing the filament intermediate its ends. These supporting members composed of insulative material -are embedded in insulation 122 on the top:ledge of a removable filarnent holder 112.

The lead-in Wires 124 I0 .the filament 98 are insulated at least along their length passing through a filarnent holder.

Referring now to Figure 7 wherein there is shown the electrical circuits, apparatus and connectiong therefrom to the X-ray tube, it Will be noted that a tube is shown in miniaiture diagrammatic form With an anode 32, cathode 26 and flexible lead-in cables 90. The original source of potential 152.is led in through a double pole =master switch 154 and placed across a variable autotransformer 156, thence t0 the primary cf the high otential transformer 158 through a rheostat 160 and The transfoimer 158 :has two separate secondary windings 164 andl66 i1e side of eacl1 being connected to ground 168 through ini1liammeters 170 and 174. In order to assure a ground ed connection at the anode 312 and the tube 150, a wire 172 may be connected from the ground point 168 of the secondaries of the high potential transforrner to the anode 32 and the tube. The other side of the secondaries 164 and 166 supply the high potential necessary for the operation of the X-ray tube and Will be more fully described below.

Bach of the five filarnents 98 located in cathodes 26 is separately connected to a filament transforrner. The primaries of the transformers 176 leading to one of the cathodes 26 are connected in parallel and have an individual balancing rheostat 178. The source of potential to the primaries of transforrners 176 is taken frorn the main source 152 With connection thereto being n1ade after switch 154. Another set of five transforrners 180 is sinnilarly connected and the prirnary circuit of each contains a balancing rheostat 182 but the secondaries thereof sup ply voltage individually to the filaments in the other cathode 26. Bach pair of lines leading to the two Sets of five transformers 176 and 180 has an individual rheostat 184 and ammeter 186 for total amperage control t each set of five filarnents. Connected in the line 188 before the bifurcation to the two sets of transformers 176 and 180 are a filarnent switch 189, a master rheostat 190 and an ammeter 192 for control of the overall filament heating current and the flow of electrons to the anode as will be seen hereinafter.

The output lines 194 of the filarnent transformers 176 are grouped together and entered into a flexible shockproof cable 196. Also coming into the cable is a high potential line 198 from the secondary Winding 164 cf transformer 158. The output lines 200 0f the filament transformers 180 are similarly grouped and entered into flexible shock-proof cable 202 with the high potential line 204 frorn the secondary winding 166 of the transformer 158 also entering the cable 282. Cables 196 and 202 separately carry their wires, represented as a single line 206 Within the cables, into rneasnring tanks 208 and 210, respectively, said tanks being preferably located near the operators station for convenience to the operator in reading the meters Within the tanks. The high potential current on line 198 in tank 208 and on line 284 in tank 210 is measured respectively by milliammeters 214-, there being one in each tank, and is superimposed through milliarnmeters 218 up0n one side 216 of each filarnent circuit in its associated tank. (Only one side of each circuit is shown in tank 214..) The filarnent lines are made available-for connection to the high potential lines 198 and 204 by utilizing a coupling adapter 220 (sirnilar to adapter 96 described above) connected to the flexible cables 196 and 202 and the filament Ii=nes inside the tanke 208 and 210, said cables being covered Within the tank by a glass or Bakelite insulating sleeve 222. A packing nut 224 located on the outside of the tank secures the cable in position. The filament lines are attached to an out-going cable 90 by an adapter 228 in the same manner as described above. Cable 90 is also insulated within the tanks by a glass or Bakelite sleeve 230 With packing nut 232 securing the cable to the tanks. The tanks 208 and 210 are filled With a transparent insulative fluid 234 such as oil, are grounded, and may be wholly constructed 0f a transparent material such as glass or of metal Wit'n a transparent window 236 for reading the milliarnrneters. lt Will be understood that the connections in tank 210 and for the cable 202 clescribed above apply also to the tank 208 and cable 196. Flexible output cables 90 are connected respectively to cathodes 26 within the X-ray tube 150.

Alth0ugh the source cf high potential has been conveniently described and shown in connection with a transfonrner 158 hav'ing two secondary windings, it is obvious that any two sources supplying proper voltages may be utilized. Also each filament circuit need not be and supplying a high potential between the anode and filarnents, each filament Will be heated sufficiently-to ernit electrons, and the high potential Will cause an electron flow to the anode. In Order toequalize the quantity and intensity cf X-rays generated at the anode target areas, it is necessary that the flow of electrons from each filament to the target area upon which it is focused be equal, thns requiring that all ten of the milliamrneters 218 rec rd the sarne amount of high potential cunrent going onto the separate filament circuits. Adjus-trnent of the balancing rheostats 178 and 182 will change the amount of high potential current allowed to flow through milliamrneters 218. Whenever any one or all cf the milliammeters 218 is out of balance (i,e. does not record the same amount of current as the others), its associated balancing trheostat is adjusted to bring the current through the rnilliammeter back into balance. In this manner, an equal flow of electrons Will result from each filan1ent, and an equal distribution of heat will be created upon the anode. In addition to preventing any bot spot on the ande (which is rather common in present day tubes), X-rays generated from the ten linear focal areas 44 provide crossfire radiation in a homogeneous manner.

It Will be understood that although this invention has been described in connection Wth X-ray apparatus having two cathodes each with five filarnents placed upon a dual faced anode and other structural and circuit details, the matter contained in the foregoing description and accornpanying drawings should be interpreted as merely illustrative and not limitative, the scope of the invention being defined in the appended clain1s.

What is claimed is:

1. X-ray apparatus capable of producing homogeneous crossfire radiations cornprising an evacuated X-ray tube, an anode at least partially disposed Within the tube and having a plurality of uniform target areas, a filter located in predeterrnined relation to the anode and sealed directly to said X-ray tube at an opening in the periphery thereof to allow passage of X-rays, a cathode structure having at least one filarnent associated with each target arrea, said structure comprising a plurality 0f foousing cups, each having a separate adjustable and rernovable solid floor section holding one of said filaments at a predetermined focus and completely covering the bottom of the cup, means for superimposing a high potential between each filament and its corresponding target area, a separate regulatable source 0f current for each filarnent for providing equal electron flow therefrom, rneans for measuring each superirnposed high otential current for assuring equalization therebetween during operation of the filament current source, and a tank disposed adjacent said tube, said tank being composed at least partially Cf a transparent material and containing a transparent high potential insulative fluid for housing the measuring means in a readable yet shockproof manner.

2. X-ray aparatus cornprising an evacuated X-ray tube cornposed substantially of metal and at ground potential, said tube having a jacket adjacent its periphery forming a channel for passage of cooling fluid therethrough, a fluid cooled anode at least partially disposed within said tube and connected electrically thereto, a filter located in predetermined relation to said anode and sealed directly to the metal portion of said X-nay tube at an opening in the periphery thereof for allowing passage of X-rays direct- 1y to the outside atmosphere for utilization, a plurality 0f cathodic filaments associated with the anode, a diiferent focusing cup for each filarnent, each cup having a separate adjustable and remo vable solid floor section holding its filament at a predetennined focus and completely covering the bottom of the cup, and a source of high potential connected n one side to each filament and on the other side -to -ground and thereby to said tube and anode so that all exposed portions of -the apparatus are at ground potential.

3. X-ray apparatus oapable of produoing 'homogeneous orossfire radiations compris'ing an evacuated X-rayiube, an anode at least partially disposed within the tube and having a plura1ity of uniform discrete target areas, a cathode structure haaring at least one filament associated with each target area, means for superimposing a high potential between each filament and its corresponding target area, and means for providing an equal flow 0f electrons from each filament so that an equal emission of X-ray results from each anode target area upon impingement by said electrons, said cathode structure comprising a plurality 05 focusing cups each having a separate adjustable and removable solid floor section ho1ding one of said filaments at a predetermined focus and complete1y covering the bottom of the cup.

4. X-ray 'apparatus comprising an evacuated X-ray tube composed substantially of meta1 and at ground potential, an a110de at least partially disposed within the tube and connected electrically to said tube, a plurality of cathodic filaments associated with the anode, a source of high potential connected on one side to sa.id filament and on 1;he 0ther side t0 ground and thereby to said tube and anode so that all exposed portions of the apparatus are at ground potential, and a different focusing cup for each filament having a separate adjuscable and removable solid floor section holding it s filament at a predeterrnined focus an1c1 completely covering the boctom of the cup.

5. A new use of X-ray apparatus including an anode having a plurality of uniform discrete target areas and at least one cathodic filament associated with each target area, said use being the produetion of homogeneous crossfire radiations and including the steps of applying a high otential between said anode and each of said filaments,

applying separate 10W vo1tages simultaneously across each of said filaments, separately but simultaneously indicating the -amount of the respective high potential filament cmrents -resulting, and regulating said1ow voltages =to cause the indicated high potential filament cunents to be simultaneously equal so as to assuredly cause an equal flow of electrons from each filament simultaneously onto che respectzive target areas and thereby provide uniform X-ray emissicm from all the difierent target areas at the same time.

6, An X-ray tube having an anode and a cathode with a plurality of filaments, said oathode comprising a focus ing cup for each different filament, each cup having a. separate adjustable and TGII IO'VBbIC solid floor section holding its filament at a predetermined focus relative to a given area on said anode and completely covering the bottorn of -the cup.

Refereuces Cited in the fi1e of this patent UNITED STATES PATENTS 688,458 Caldwell Dec. 10, 1901 1,907508 Coolidge May 9, 1933 1986,466 Ehrke Jan. 1, 1935 2,049,275 Simon July 28, 1936 2130020 McEuen Sept. 13, 1938 2139966 Loebell Dec. 13, 1938 2,213112 Timmons Aug. 27, 1940 2,215,426 Ma0hl&tt Sept. 19, 1940 2350642 Schwartzer Inne 6, 1944 2362,816 Harker Nov 14, 1944 2471298 Atlee May 24, 1949 2515,021 Simpson July 11, 1950 2,517171 Bernrenter Aug. 1, 1950 2,518539 Graves Aug. 15, 1950 2597,498 Kerkhofi May 20, 1952 2,663812 Jamison et a1. Den. 22, 1953 2692340 Reiniger Oct. 19, 1954

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