CA1177179A - Device for the storage of a photon source and the radiation of a body - Google Patents

Abstract

The invention relates to a device for storing a photon source and for irradiating a body with radiation from said source. This device comprises a biological protection body having a cylindrical cavity and two passages opening into the cavity and on the external wall of the body, a biological protection disc in the body cavity, having a housing opening onto the side wall of the disc and a sinuous passage opening into two zones of the side wall of the disc capable of being simultaneously opposite said passages of the body, a source of radiation y in the disc housing, at least one optical fiber disposed in the passage of the disc , a collimator arranged at the right of one of the passages of the body, an optical device at the right of the other passage of the body and means for rotating the disk between a first position for which the source is facing vis the collimator and a second position for which the two ends of the fiber are respectively vis-à-vis the optical device and the collimator.

Description

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The subject of the present invention is a device storage of a source of photons y and irradia-tion of a body by the radiation of said source. The device applies to human and veterinary therapy nary, metrology, biology, in particular research, medicine and veterinary research.
The invention also relates to a method for transporting and replacing a radioactive source in an irradiation device.
More precisely, the invention relates to a dis-positive of the type comprising a biolo-gique, an element of support disc of a source of photons mobile in said body between a first ~ re tion allowing the storage of the source in good biological protection conditions and a second position allowing emission outside the body of a photon beam, a precollimator to limit the beam has a given area of the body irradiated. For certain applications, such as telecobal-therapy, the device according to the invention further comprises an optical assembly for generating a beam light simulating the photon beam and a device tif of secondary collimation.
We know ~ t devices of the aforementioned type designed prior to the present invention which comprises carry a support element of a photon source, mobile in translation, and an optical assembly made up by a light source, such as a light bulb neuse, which is carried by the support element of the source.
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Also known, in particular by the American patent 2,9Sl, 162, devices which have a metal casing providing biological protection against radiation from 5 radioactive source, inside which is a cylinder movable in rotation around its axis lon-gitudinal. This cylinder has two longitu-diametrically opposed. The radioactive source tive is mounted on a removable bar playing the role 10 of biological protection and engaging in one said longitudinal holes. A light source mounted on a similar bar engages in the second longitudinal hole. The protective envelope includes a conical opening for the passage of radiation 15 of the source and that of the light beam.
Such known dispositi ~ s have a number of drawbacks. In particular, they are of high weight and relatively large important. This leads to an annoying imbalance in 20 the case of certain applications for which the irradiation device is animated by a movement rotation, such as therapeutic treatment of a patient by irradiation of part of his or-ganism.
Another disadvantage of ir-known radiation is constituted by a fact that it is necessary to access the interior of the device to change the light source or radioactive source ~
Finally, type irradiation devices 30 known, using radioactive sources, present another disadvantage i ~ bearing which is the changament of these radioactive sources when they lost over time a specified amount of their activity. In particular, when these devices are 35 used in radiotherapy, it is necessary to suspend B 6481.3 LW

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their use and ask a specialized team to change these sources on the spot with suitable equipment.
In addition, for certain applications such that a patient's therapeutic treatment it's necessary to deliver a beam of photons of dimensions precise and adjust the position of this beam.
Irradiation devices of known type, which include an optical system illuminating on a solid angle of 10 4 ~ steradians, do not allow precise simulation of the photon beam.
The present invention is precisely for object a device for storing a photon source and irradiation of a body by the radiation of 15 this source which remedies the drawbacks of the devices previously known.
An object of the present invention is a irradiation device for delivering a beam photons of precise dimensions, easily adjustable, 20 with a device ensuring a first collimation.
Another object of this invention is to provide a device for changing the radioactive sources without resorting to manipulation delicate lations at the place of use 25 of the apparatus.
The irradiation device according to the present invention overcomes these disadvantages, in that it serves both as a storage device and as a device irradiation. The radioactive source is put in place 30 inside the support disc, its setting is made at the time of manufacture. The device with its source already set is then transported at the place of use. Then just mount it in ~ fa removable, for example by means of screws, on 35 a support arm, so that it is ready to operate B 6481.3 LW

without any additional adjustment. When at the end of a determined time, the activity of the radio source active having decreased, it became necessary to replace, the irradiation device is disassembled 5 of its support arm, and an irradiation device identical with a new source mounted on its place. This avoids the need for labor specialist, to change the source.
More specifically, the storage device 10 of a photon source and a body irradiation by the radiation of said source is characterized in that it includes:
- a biological protection body having a cylindrical cavity of ci section ~ circular and two ~ passages 15 said first and second passages respectively, these passages leading to either of their ends in said cavity and on the outer wall from the body, - a biological protection disc, of complete shape 20 mentally to that of the body cavity and having, on the one hand, a housing centered on a perpendicular axis at the axis of the cavity, this housing d ~ ebou ~ haunts on the side wall of the disc, - A source of radiation Y con ~ enue in said 25 accommodation, - a pre-collector placed in front of said first passage, - Means for rotating said disc between a first position for which said source 30 is facing the precollimator and a second position for which the source is in position of storage.
This device notably has the advantages following:
- it can, thanks to its compactness, be easily mounted ~

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on its support in operational position, and thanks the presence of integrated biological protection self-sufficient, be used directly for the transport of radioactive sources, this biological protection being partially constituted depleted uranium. This storage function of the source avoids all loading operations or unloading the source at the place of use.
- It has a small footprint ~ t, while ensuring good biological protection and by opposing direct or diffuse radiation leaks, thanks when using a rotating disc for setting place of photon source, - it is removable, and can be dismantled easily of its support arm, - finally, the use of depleted uranium, the radiation absorption capacity is greater to lead, to achieve biological protection allows to lower the weight of this device. This allows in particular to reduce its imbalance when it is mounted on an arm supported by a movement of rotation.
For some applications, it is necessary to deliver a light beam of precise dimensions and easily adjustable to locate the beam irradiation. For such applications, the disc of biological protection of the storage device if the invention further presents a passage arranged in the plane of the disc containing the axis of said housing, this passage leading to both of its ends in two areas of the side wall of the disc likely to be simultaneously opposite of said first and second passages r - at least one optical fiber placed in said passage of the disc, the ends of said fiber called respec-both receiving and transmitting ends being B 6481.3 LW

~ intervened at the right of each end of the said passage through fastening means removable, - an optical device integral with said body for 5 generate a light radiation on the end receiving said fiber, this device being arranged to the right of said second pass.
This preferential arrangement allows a perfect simulation of the photon beam thanks to 10 when using the emitting ~ ice end of the fiber optigue likely to be defined and positioned precisely ; on the other hand, it replaces easy cementing of the optical device intended to generate light radiation on the receiving end 15 of optical fiber.
The irradiation device according to the invention also allows, when the source is in position storage, to access each of the ends of the optical fiber through the passage of the body to the right of which 20 the optical device is arranged, this while limiting two, the fixed positions of the protective disc organic. Thus, after dismantling the optical device, it is easy to introduce or extract optical fiber in the short passage of the disc, and adjust its 25 positioning to the right of the extremi ~ és of said passage.
According to a preEerential provision of the invention, the axes of the receiving extremities and emitting fiber, define a neighboring angle from 90 ~. This provision makes it possible to make minimal 30 the irradiation of optical fiber during operation operation of the device.
According to another preferential provision of the invention, the angle of rotation of the pro-tection when the source passes from the position of B 6481.3 LW

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storage at the irradiation position, is 110.
This arrangement limits the flow of leaks radiation from the source, when the latter is in storage position. It also allows limit the height of the surrounding protective body the disc.
According to the invention, the st ~ ckage device of a photon source and a body irradiation ~ ar the radiation of the latter, includes 10 preferably on the one hand electrical locking means lage of the disc in said first position allowing irradiation, and secondly, mechanical means to automatically place the disc in said second position corresponding to the storage of the 15 source Furthermore, the body is preferably consisting of a mass in which is included a depleted uranium block, this block defining the portion of the wall of the cavity located around said source 20 when said disc is in the storage position.
An important advantage of the invention is that it allows a quick replacement of the source radioactive.
To this end, the invention also has for 25 subject a method of replacing and transporting a radioactive source. This process is characterized in that that it comprises the following successive stages:
- we transport to the place of use a irradiation device provided with a new source prior to properly adjusted and ready for use, the irradiation device playing the role of a radiopro-tection, - the irradiation device carrying the sourc ~ used of the support arm on which it is fixed, - the irradiation device comprising the the new and preset radioactive source.

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So the delicate source setting is performed at the time of manufacture of the device.
Disassembly of the irradiation device comprising the used source, then mounting the irra-dl.ation neuf is carried out in a simple way, without requiring any additional adjustment, and consequently without the need for a hand of specialized work.
Other features and benefits.
10 the present invention will appear more clearly on reading the following description of an example for making the device of the given invention by way of illustration and in no way limitative, with reference to the accompanying drawings in which:
- Figure l shows schematically an example of an installation; of the irradiation device according to the invention, - Figure 2 shows a cross-section dirty storage and irradiation device according to 20 invention - la.figure 3 represents a longitudi section nale of this same device, - Figure 4a shows a view along direction IV of fi ~ ure 3, - Figure 4b shows a detail view the precollimation device, - Figures 5 and 6 show the detail of the protective disc force feedback system organic.
FIG. 1 shows a device which can be used advantageously in radiotherapy. This device has a support fixed 1, an arm 2 movable around an axis XX, a provision irradiation setter 3 mounted on ~ removable hook 35 the movable arm 2, a precollimator 13 and a device of secondary collimation 4 of axis YY. Collimator 4 is removably attached to the movable arm 2 by means of a support plate 15, fixed by screws 16.
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There is shown in Figure 2, a section transverse of the irradiation device 3 of FIG. 1.
This irradiation device includes an enclosure 5 having the shape of a bowl provided with a rim 6.
S This enclosure 5 can be removably attached on the arm 2 by means of screws passing through this rim 6.
A fixed shield 7 of biological protection is placed inside the enclosure 5. The shield 7 at least partially surrounds a protective disc 10 biological 8 mobile in rota ~ ion around a passing axis by its center C. The disc 8 is provided with a logmeent 9 intended to receive a radioactive source. This accommodation 9 opens towards the outside of the disc 8 so as to pass the photon beam delivered by 15 the radioactive source 10. The fixed shield 7 consists of a block of depleted uranium 7a, embedded in a block lead 7b. The depleted uranium block 7a surrounds the photon source when the latter S2 finds in the storage position shown in lines 20 mixed in Figure 2. The ability of uranium to absorb the radiation being about twice as much to that of lead, the use of a block of uranium depleted provides biological protection satisfactory, while ensuring, a reduction in weight and size of the irradiation device according to the invention.
~ years the example of realization shown in FIG. 2, an optical fiber 11, intended for transmit a luminous flux, is arranged in the disk 8. The optical fiber 11 leads to one of its ends lla, called the receiving end, in look of a light source 12 fixed to the outside of enclosure 5 and at its other end llb, called emitting end, along the YY axis. Each of B 6481.3 LW

receiving and transmitting ends is maintained by by means of adjusting their positioning.
The optical device 12 focuses light radiation on the receiving end of the optical fiber 11, this optical device 12 can for example consist into a light source associated with a reflector for focusing his fa; uminous seal. By radiation bright, it should be understood in this text electromagnetic radiation located in the part 10 visible from the spectrum.
The passage provided in disc 8 of the optical fiber 11 has a substantially recti-line, except for its ends. Preferably, the emitting and receiving ends of the fiber 15 11 determine an angle at the center equal to 90. A
such a provision makes it possible to minimize the irradiation of optical fiber during the operation of the device. We have designated in Figure 2, by the angle of rotation of the disc 8 which makes it possible to pass from the 20 radioactive source irradiation position 10 shown in solid lines, in the storage position from the same source, represented ~ ée in phantom.
The value of the angle a is llG. This value allows to limit the rate of radiation leakage when 25 radioactive source 10 is in storage position as well as the height of the body of biological protection 7 surrounding the disc 8.
There is shown in Figure 3, a section view of the irradiation device shown 30 in FIG. 2. This view shows in particular the seems to position the disc 8 capable of ensuring rapid alternation of irradiation positions and storage, with disc lock in position irradiation and return of the latter to position 35 of storage during a security action or in the possibility of an electrical failure.

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The disc 8, mounted on bearings 15, is integral in rotation with the shaft 16. A disc clutch 18 is mounted on the shaft 16. A
pi.gnon 20, free mounted. in rotation on the shaft 16, can be coupled to this shaft by means of the clutch electromagnetic 22. When the electromagnetic clutch 22 is powered, the shaft 16 is rotated by the pinion 24 of the gear motor 26. On the other hand, the shaft 16 is integral in rotation, for example by means of keying, a pinion 30 entering;
a rack 32 which is intended to define the disc irradiation and storage positions 8.
We have also shown schematically in dashed lines, the movable arm 2 on which is 15 mounted the device of the invention, the device maintaining the position of the disc 8 designated by the reference 36 and finally, the display device 38 disc position. These devices will be described in more detail with reference to Figures 4, 5 and 6.
FIG. 4a shows a vuP
according to arrow IV of FIG. 3, of the device represented felt on this figure. This figure shows in particular the device 41 for detecting the position of the disc 8.
Rack 32 is likely to be 25 moved by a gearmotor between a first position, shown in solid lines in FIG. 4, for which it abuts against an electro-magnetic 35 adjustable in position by means of a nut 39, and a second position, shown in lines 30 mixed in Figure 4, for which the rack 32 is located near a shock absorber assembly 40 whose action is re ~ lated by positioning of the rod 42.
An electrical contact 41 controls the stopping 35 of the electromagnetic clutch 22, when the rack 32 succeeds, being moved in the direction of B 6481.3 LW

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arrow f, a short distance from the suction cup electromagnetic 36. Furthermore, to allow the automatic return of the disk 8 to the storage position, a spring 44 is interposed between a wall of the 5 rack 32 and a fixed wall integral with the enclosure 5, so that the disc plays automatically according to the direction of the arrow F of the position d! irradiation to the storage position when a safety device or during a power failure.
1 A deu ~ th electrical contact 46 actuated by finger 45, used to determine the position end of stroke of rack 32 when it this is near the shock absorber 40.
Finally, a third ~ electrical contact 48 used to determine the start of irradiation. In indeed, the debut of this irradiation is determined by the time the radioactive source 10 begins to appear in the pre-collimator. This position ! 20 from the source designated by reference 10a has been shown felt in Figure 4b.
Finally, we have shown, in dashed lines, in fig. 4a, a second position lOb of the source radioactive, which corresponds to a slight overshoot 25 by the radioactive source 10 of the axis position YY of the collimation device. This provision aims to allow an inevitable game catch-up lz rack and plgnon training.
5 is shown in Figure 4b the 30 precollimation device with, in addition, shown in dashed lines a secondary collimation device 50 associated with the irradiation head.
Figures 5 and 6 show the detail of the system allowing the force to return 35 disc 8 in case of an incident. This device, designated ;

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by general reference 38, consists of a knock 60 made integral with the shaft 16 by means of a keying.
The toc 60 carries a toc finger 62. The rotation of the toc 60 is limited by two stops 64 and 66. The stop 5 64, which is a rubber stopper, corresponds to the irradiation position. Stop 66 corresponds at the storage position of the radioactive source 10. On the other hand, a disc 68 is integral with the knock 60. The disc 68 has corresponding colored zones 10 at the different positions of the disc. We thus find successively a corresponding green area 68a at the storage position and a corresponding red area 68c laying in the irradiation position.
A lever 70, whose angular movement is limited, mounted mad on the end of the shaft 16. This lever allows the force control of the disc 8 by means of the toc 60. We note that the tree 16 does can be entered; born thanks to this device only in 20 one direction, this direction corresponding to the passage from the position irradiation at the storage position.
There is shown in Figure 5, in lines mixed, positions 70a and 70 ~ of lever 70 which correspond respectively to the irradiation positions 25 and storage. An external indexing 72 located in look of the disaue 68 per ~ and determine thanks to colored areas of this disc its position.
The irradiation device which has just been described, has the important advantage of also serving 30 also a radiation protection castle for the transport of the radioactive source. This adjusts the factory source, at the time of manufacture, and perform in a simple way, without resorting to manpower specialized, change of radioactive source.
35 for this, we carry an irradiation device provided with a new source previously adjusted and ready during use at the place of use, the irradiation device playing the role of a castle radiation protection.
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Claims (9)

The realizations of the invention on the subject of-which an exclusive property right or privilege is claimed, are defined as follows: 1. Device for storing a source of photons and irradiation of a body by radiation from said source, characterized in that it comprises:
- a pre-biological protection body feeling a cylindrical cavity of circular section and two passages called first and second respectively passages, these passages leading to both of their ends in said cavity and on the wall external of the body;
- a biological protection disc, shape complementary to that of the body cavity and having, on the one hand, a center housing on an axis perpendicular to the axis of the cavity, this housing opens out edge on the side wall of the disc, and presenting, on the other hand, a passage arranged in the plane of the disc containing the axis of said housing, this passage opening at either end in two zones of the side wall of the disc likely to be simulated temporarily opposite said first and second pass ges;
- a .gamma radiation source. contained in said accommodation;
- a pre-collector willing to the right of-said first pass;

- means for rotating the said disc between a first position for which the-said source is opposite the precollimator and a second position for which the source is in posi-storage;
- at least one optical fiber arranged in said passage of the disc, the ends of said fiber respectively said receiving end and é-being maintained at the right of each of the mites of said passage by means of removable fasteners;
- an optical device integral with said body to generate light radiation on the outside mite receiving said fiber, this device being disposed at the right of said second passage. 2. Device according to claim 1, charac-terized in that the axes of the receiving ends and emitting fiber define an angle close to 90 °. 3. Device according to claim 1, charac-terized in that it includes electrical means of locking the disc in said first position. 4. Device according to any one of the re-vendications 1 to 3, characterized in that it comprises mechanical means to automatically place the disc in said first position. 5. Device according to any one of claims 1 to 3, characterized in that said device that is a sintered tungsten. 6. Device according to any one of claims 1 to 3, characterized in that said body consists of a lead mass in which is included a depleted uranium block, this block defining the portion of the wall of the cavity located around said source when said disc is in said second position. 7. Device according to claim 1, ca-characterized in that said means for moving said disc comprise a shaft coupled, on the one hand, to a gearmotor via an electro- clutch magnetic and, on the other hand, to a movable rack between two corresponding extreme positions ment to said first and second positions of the disc. 8. Device according to claim 7, ca-characterized in that the extreme position of the rack-re corresponding to said second position of the disc is defined by an electromagnetic stop capable of ver-rust the rack, this stop acting in the against a spring capable of recalling the rack in an extreme position defined by a mechanical stop. 9. Device according to any one of claims 1 to 3, characterized in that the enclosure of the irradiation head comprising the precollimator is provided with flanges allowing its temporary fixing, by means of screws, on the movable arm.