WO2011064388A1

WO2011064388A1 - Device for producing radioisotopes

Info

Publication number: WO2011064388A1
Application number: PCT/EP2010/068523
Authority: WO
Inventors: Andrea Cambriani; Michel Degeyter
Original assignee: Ion Beam Applications S.A.
Priority date: 2009-11-30
Filing date: 2010-11-30
Publication date: 2011-06-03
Also published as: BE1019054A3

Abstract

The present invention relates to a device for producing radioisotopes by means of irradiation of a radioisotope precursor using a particle beam, as well as a method for producing radioisotopes.

Description

DEVICE FOR PRODUCING RADIOISOTOPES TECHNICAL FIELD

The present invention relates to a device for producing radioisotopes having a target in which a radioisotope precursor of interest is irradiated by a particle beam.

DESCRIPTION OF THE PRIOR ART

In nuclear medicine, positron emission tomography is an imaging technique requiring radioisotopes emitting positrons or molecules labeled with these same radioisotopes. ¹⁸ F is one of the most commonly used radioisotopes among others such as ¹³ N, P ¹⁵ 0, or ⁿ C. The ¹⁸ F has a half-life of 109.6 min and can be transported to other sites than its production site.

¹⁸ F is most often produced in its ionic form and obtained by the bombardment of accelerated protons on an irradiation cell comprising water enriched in ¹⁸ 0. Many irradiation cells were developed all having for the same purpose to produce ¹⁸ F ^" in a reduced time with the best performance.

[0004] Generally, a device for producing radioisotopes comprises a proton accelerator and a target. This target comprises a cavity, inside which is included the radioisotope precursor in liquid form. Generally, the energy of the proton beam directed on the target is of the order of a few MeV to about twenty MeV. Such a beam energy causes a heating of the target as well as a vaporization of the radioisotope precursor, thus reducing the stopping power of this precursor and therefore the production yield of radioisotopes. A target cooling device must therefore also be implemented in order to attempt to maintain the radioisotope precursor in liquid form, or at most in the form of an intermediate state between liquid and vapor. The document by E. Galialo et al. The Cyclotron Production of Carrier-free 77Br via the 79Br (p, 3n) 77Kr 77Br Reaction using a Target Liquid and On-line Extraction ", Appl. Radiat. Isot. Flight. 49, Nos. 1-2, pp.105-111, 1998, describes a device for producing ⁷⁷ Br comprising a cyclotron capable of producing a proton beam of 40 MeV, a cylindrical target comprising a solution of NaBr or LiBr, the bromide being the radioisotope precursor ⁷⁷ Kr which decays to ⁷⁷ Br with a half-life of 30 min. Such a beam energy requires a powerful cooling system.

In addition, in the case of the production of ¹⁸ F ^" , because of the particularly high cost of the precursor, water enriched in ¹⁸ 0, only a very small volume of this precursor, at most a few milliliters, can to be placed in the target cavity, therefore, the problem of heat dissipation produced by the irradiation of the target material on such a small volume is a problem to be overcome.Typically, the power to be dissipated for an energy beam of 18 MeV an intensity of 50 to 150 μΑ is between 900 W and 2700 W, and this on a volume of radioisotope precursor generally between 0.2 and 5 ml, for irradiation times ranging from a few minutes to several hours.

Due to this problem of heat dissipation in the target material, the beam intensities for the production of ¹⁸ F ^" radioisotopes are generally limited to 50 or 60 μΑ. Current cyclotrons used in nuclear medicine allow reach beam current intensities ranging from 80 to

150μΑ or more. The possibilities offered by the current cyclotrons are therefore unexploited.

The present invention aims to provide a device and a method for producing a radioisotope by irradiating a target comprising a liquid comprising a radioisotope precursor. More particularly, the device and the method according to the present invention are intended to allow during the irradiation step to minimize target heating in order to minimize the vaporization of the liquid comprising the radioisotope precursor.

SUMMARY OF THE INVENTION [0008] According to a first aspect, the present invention relates to a device for the production of radioisotopes by irradiating a precursor of radioisotopes using a particle beam. said device comprising: a target comprising a chamber for receiving a liquid comprising a precursor of radioisotopes, said target comprising orifices for introducing said liquid into said chamber or for discharging said liquid from said chamber;

means for cooling said target; said device being characterized in that it comprises

a wheel on which said target is mounted, and;

a motor capable of rotating said wheel;

and in that said target is mounted on a plane formed by the periphery of said wheel, so that during the rotation of said wheel, the region of impact of the beam on the target changes continuously.

Preferably, the device of the present invention comprises an axle supporting said wheel, the axle being parallel to the axis of said beam.

Preferably, the device of the present invention comprises a device for loading-unloading said liquid allowing the introduction of said liquid into said chamber or the evacuation of said liquid out of said chamber, conduits out of the charging device- unloading being coupled to other conduits connected to said orifices of said target and included in radii of said wheel and in said axle.

Preferably, the device of the present invention comprises a shutter located on said axle, the shutter being articulable between a first position allowing the liquid to pass so as to enter the target or exit the target and a second position blocking the passage of the liquid so as to maintain it within said target.

Preferably, the device of the present invention comprises an injector comprising the ends of said pipes leaving the device for loading and unloading the liquid, said injector being connectable to the conduits connected to said orifices of said target.

[0013] Advantageously, the target of the device of the present invention is circular in shape.

Preferably, the device of the present invention comprises collimator located in the axis of said beam, and whose opening area is less than the area. the surface of the target, so that a portion of said target is irradiated by the beam, thus minimizing the heating of said target.

[0015] Preferably, said target of the device of the present invention comprises:

a first sheet held against the spokes of said wheel;

a spacer attached to said wheel, and now said first sheet;

a second sheet separated from said first sheet by said spacer; means for fixing said second sheet against said spacer and;

sealing means located on either side of said sheets;

forming said chamber.

Preferably, said orifices of said chamber are located opposite each other in said spacer.

Preferably, said cooling means of said target comprise:

a first cavity situated at the front of the target between said target and said collimator, said first cavity through which a flow of gas passes;

a second cavity located at the rear of the target and traversed by said axle, said second cavity through which a flow of cooling fluid passes;

- sealing means disposed on parts of the device capable of rotating against other static parts of the device which also comprises sealing means so that the sealing of each cavity is ensured;

said first and second cavities comprising said target.

Preferably, said second cavity comprises an arrival of cooling fluid facing said impact region of the beam on said target.

In the device of the present invention, said chamber advantageously comprises a liquid drive means between said first and second sheets of said chamber.

In a second aspect, the invention relates to a method for producing radioisotopes comprising the following steps:

Filling a chamber of a target with a liquid comprising a precursor of radioisotopes;

rotating said target and irradiating said target, so that the region of impact of the beam on said target changes continuously, so that heating of the target by irradiating the beam is minimized; stopping irradiation and rotation of said target;

draining said target.

The method of producing radioisotopes uses a device as described above.

[0022] Preferably, the method using the above device comprises the following steps:

(i) communicating said loading-unloading device with the orifices of said chamber;

(ii) loading the radioisotope precursor liquid in said chamber;

(iii) closing the communication of said loading-unloading device with the orifices of said ducts located on the outer surface of the axle;

(iv) actuation of the motor rotating the chamber about an axis of rotation coincides with the axis of the axle of the device;

(v) irradiating, by a beam produced by a particle accelerator, said cooled chamber by a cooling device;

(vi) stopping the irradiation and the motor;

(vii) placing the said loading-unloading device in communication with the orifices of the said chamber by the said communication means;

(viii) discharging the irradiated liquid comprising the radioisotope of interest to a container.

BRIEF DESCRIPTION OF THE FIGURES

The following figures are given for information only and do not constitute a limitation of the present invention. Moreover, the proportions of the drawings are not respected.

[0024] FIG. 1 shows a side section of a device according to the present invention in the presence of a particle accelerator, the device comprising a first embodiment of a shutter, the shutter being in a position as adopted during the liquid loading or unloading step.

[0025] FIG. 2 shows a detailed side section of the target of the device according to the present invention, the target being assembled on a wheel supported by an axle.

Fig. 3 3 shows a side section of a portion of the device of the present invention showing in more detail the device for loading and unloading the liquid.

[0027] FIG. 4 shows a side section of a device according to the present invention, in the presence of a particle accelerator, the device comprising said first embodiment of the shutter, the latter being in a position as adopted during the irradiation step.

[0028] FIG. 5 shows a side section of a portion of the axle comprising the first embodiment of the shutter, the shutter being articulable and shown in a position permitting the transfer of fluid between the conduits external to the axle and conduits included in the axle, the position in which the ports included in the shutter coincide with the orifices of the conduits included in the axle, the orifices being located on the periphery of the axle.

[0029] FIG. 6 shows a cross section of a portion of the axle comprising the first embodiment of the shutter in a position identical to that of FIG. 5

FIG. 7 shows a side section of a portion of the axle comprising the first embodiment of the shutter shown in a position preventing the flow of liquid, wherein the ports included in the shutter are offset from the orifices of the conduits. included in the axle, the orifices being located on the periphery of the axle.

[0031] FIG. 8 shows a cross section of a portion of the axle, comprising the first embodiment of the shutter in a position identical to that of FIG. 7.

[0032] FIG. 9 represents the device according to the present invention in the presence of a particle accelerator and comprising a second mode of performing a shutter in a configuration as adopted during the step of loading or unloading the liquid.

[0033] FIG. 10 shows the device according to the present invention in the presence of a particle accelerator and comprising the second embodiment of the shutter in a configuration as adopted during the irradiation step.

[0034] FIG. 11 shows a detailed view of a part of the axle comprising the second embodiment of the shutter, the shutter comprising electro valves located at the inlet of the ducts included in the axle, the solenoid valves being in a configuration as adopted during the irradiation step.

[0035] FIG. 12 shows a detailed view of a part of the axle comprising the second embodiment of the shutter, the shutter comprising electro valves located at the entrance of the ducts included in the axle, the solenoid valves being in a configuration as adopted during the loading or unloading step.

FIG. 13 shows a side section of a variant of the device of the present invention, comprising a target comprising a means for driving the liquid. DESCRIPTION OF THE EMBODIMENTS OF THE INVENTION

FIG. 1 shows a side section of a device 100 according to the present invention. The device of the present invention comprises a target 1 comprising a chamber 4 into which can be introduced a liquid comprising a radioisotope precursor. Said target 1 comprises orifices 7, 8 for the introduction of said liquid into said chamber 4 or the evacuation of said liquid from the chamber. In addition, FIG. 1 shows a particle accelerator 2 producing a beam 3 directed on the target 1. The device of the present invention comprises means for cooling the target, the cooling means comprising a first cavity 13 and a second cavity 11 comprising the target 1 The device of the present invention also comprises a wheel 40 on which is mounted the target 1, and a motor capable of rotating the wheel 40. The target 1 is mounted on the plane formed by the periphery of the wheel 40, so that during the rotation of the wheel, the impact region of the beam changes continuously.

The device further comprises an axle 5 supporting the wheel 40, said axle 5 being parallel to the axis of said beam 3. The axle 5 supports the wheel 40 comprising spokes 35 and on which is assembled the target 1 .

The target 1 may for example be circular in shape, for example in the form of a cylinder whose height of the longitudinal axis is smaller than the diameter, as shown in Figs. 1, 2, 3, 4, 9, 10 and 13.

A collimator 14 is located between the particle accelerator 2 and the target 1. Preferably, the collimator opening diameter is smaller than the diameter of the target, so that part of the target is irradiated. by the beam, thus minimizing the warming of the target. Advantageously, the opening of the collimator is located facing a portion of the periphery of the target. During the irradiation step, the motor 6 is actuated and the target 1 rotates about the axis of the axle with a certain frequency, advantageously greater than 500 revolutions / min, preferably between 500 and 15000 rev / min. more preferably between 1000 and 10000 rpm, still more preferably between 1000 and 5000 rpm. By rotating the target, the region of impact of the beam on the target changes continuously while the remainder of the unexposed target beam can cool more efficiently.

The fïg. 2 has a detailed side section of the target 1 assembled on the wheel 40 supported by the axle 5. The target 1 comprises a first sheet 9, having a thickness of between 100 micrometers and 1 millimeter, located against the spokes 35 of the Wheel 40. A spacer 24 comprising a passage for conduits 17, 18 is fixed to the wheel 40 by screws 34 and holds the first sheet 9 against the wheel 40. O-rings 41 are provided to provide a seal. A second sheet 10, of a thickness minimizing the energy losses of the beam, for example of a thickness of between 10 micrometers and 100 micrometers, is located on the other side of the spacer 24 and is held against it by a fixing means 23, for example a ring 23 fixed by screws 34. O-rings 41 also seal the fixing of the second sheet 10 on said spacer. Target 1 is assembled to forming a sealed chamber 4 whose volume is between 0.5 cm ³ and 30 cm ³ , more preferably between 5 cm ³ and 20 cm ³ . The target is advantageously of cylindrical shape whose height is calculated as a function of the energy of the beam used and as a function of the thickness of the second sheet 10, so that the height of the cylinder is greater than the depth of penetration beam in said target when it is filled by the liquid comprising the radioisotope precursor. Advantageously, the target is of cylindrical shape whose height is less than the diameter of the base of the cylinder.

The said chamber 4 included in the said target 1 can accommodate a radioisotope precursor in liquid form such as water enriched in ¹⁸ 0 for the production of ¹⁸ F ^~ , the ¹⁸ F ^~ being obtained by bombarding said enriched water ¹⁸ 0 with accelerated proton beam. The said proton beam may be obtained by a particle accelerator such as for example a cyclotron or a linear accelerator (LINAC).

The parts of said target 1 in contact with the liquid and capable of being irradiated are made of a material chosen for its acceptable thermal properties as well as for its chemical inertness. The said material chosen is for example niobium not producing radioisotopes whose half-life time exceeds 24 hours. For reasons of cost and ease of construction, only the said first sheet and second sheet and the said spacer are made of niobium, the other parts such as the axle, the wheel and the retaining ring of the second sheet are made of another chemically inert material such as stainless steel which is not subjected to irradiation of said particle beam and therefore does not pose problems in terms of chemical inertness.

The cooling means of the target comprise two cavities 11, 13. A first cavity 13 is located at the front of the target, between the collimator 14 and the target, said first cavity 13 through which passes a flow inert gas, for example helium, from an entrance directed to the surface of the target irradiated by the beam. This flow of inert gas is mainly intended to drive out the air and to help the cooling of the target. A second cavity 11 is located at the rear of the target 1, said second cavity comprises a water inlet 12 facing the impact region of the beam 3 on the target, the water inlet 12 projecting a flow of turbulent cold water on the rear of said target.

Said first cavity 13 is separated from said second cavity 11 by said target 1 on which said ring 23 comprises mechanical seals 19 rotating against other mechanical seals 20 fixed to the walls of said first cavity 13 The said mechanical seals 19, 20 provide a seal between the first cavity 13 through which a flow of gas passes and the said second cavity 11 in which circulates a cooling fluid, for example water. Preferably, the mechanical seals 19, 20 are made of a material comprising graphite.

The axle 5 passes through a wall of the second cavity 1 1 located at the rear of the chamber. In order to ensure the sealing of the second cavity 11, a mechanical seal 21 is located on the axle 5 where it passes through the wall of said second cavity 11, said mechanical seal 21 rotating against a another mechanical seal 22 located on the surface of the hole formed in said wall of the cavity 11 through which said axle 5 passes.

The collimator 14 is located between the target 1 and the particle accelerator 2, exposing a portion of the target 1 to the beam 3 produced by the particle accelerator 2. More precisely, the collimator 14 is separated from the particle accelerator through a vacuum chamber 16 through which the beam 3 passes. Said vacuum chamber 16 is separated from said first cavity 13 located in front of the target 1 by a metal sheet 15 wedged between the outer wall said first cavity 13 and the collimator 14.

The spacer 24 comprises two orifices 7, 8 for loading and unloading the liquid. When the motor 6 is stopped, a first orifice 8 of the chamber 4 for the loading and unloading of the liquid is advantageously located downwards around the periphery of the chamber while a second orifice 7 of the chamber 4 is preferably located upwardly around the periphery of the chamber 4, so that said target is in a position allowing the loading or unloading of the liquid, as shown on the fij. 1, 3, and 9 ,. The said second orifice 7 is intended to evacuate the overflow of liquid during the step of loading the liquid in the chamber or to introduce gas that pushes the liquid out of the chamber during the step of discharging the liquid.

A loading-unloading device 50 shown in detail on FIG. 3 allows the liquid to be loaded into the target or the liquid discharged out of the target. Duct 67, 68 exit the loading-unloading device and are coupled via an injector 25 to other conduits 17, 18 connected to said orifices 7, 8 of the target, said ducts 17, 18 passing through the axle 5 and the spokes of the wheel.

The loading-unloading device 50, shown on FIG. 3 comprises three containers 27, 28, 42, a six-way injection valve 45 A, B, C, D, E, F, for example a six-way valve marketed under the name Rheodyne valve, model 7030. A first channel A is connected by a conduit to a three-way valve 44 itself connected to a syringe 43 and to a container 28 comprising the radioisotope precursor. A second path B is connected via a conduit 68 to an injector 25 mounted on a means capable of translational movement, the injector 25 connecting the conduit 68 to the conduit 18 included in the axle and intended for the loading and unloading of the liquid. A third channel C is connected to a container 27 intended to collect the irradiated liquid containing the radioisotope, this container being advantageously placed in an armored cell in which there is a device for radioisotopic labeling of molecules of interest, for example a device of 2- [18F] fluoro-2-deoxy-d-glucose synthesis. A fourth channel D is connected to a container 42 intended to collect the overflow of liquid during the loading of the chamber. A fifth channel E is connected via a duct 67 to the injector 25 connecting the duct 67 to the duct 17 included in the axle 5 and intended to evacuate the overflow of liquid during the liquid charging step or the introduction of gas during the step of discharging the liquid from the chamber 4. A sixth channel F is connected to a tank of inert gas such as helium.

The injector 25 comprising said conduits 67, 68 out of said loading-unloading device 50, can be inserted into orifices 77, 78 ducts 17, 18, said orifices 77, 78 being located at the level of the axle 5. A shutter 29, defined as a means for controlling the arrival of gas or liquid in a duct, comprises for example a ring slider 5 surrounding the axle 5, the shutter being articulable between a first position allowing the liquid to pass so as to enter the target or to get it out of the target, and a second position blocking the passage of the liquid so as to keep it inside the said target. Figures 5 and 6 show respectively a longitudinal and transverse view of the position of the ring on the axle in load-unloading mode. The sliding ring 29 comprises two ports 33 provided with O-rings 39, the ports 33 being able, depending on the position of the ring on the axle, to coincide with the orifices 77, 78 of the ducts 17, 18 included in the axle 5 The axle 5 is surrounded by three O-rings 30, 31, 32 arranged at relatively close intervals and two of these seals 30, 31 are arranged on either side of the orifices 77, 78 of the ducts 17, 18. The fij. 7 and 8 respectively represent a longitudinal and transverse view of the connection device surrounding the axle 5. A mechanical device makes it possible to slide the ring 29 on the axle from the position where the ports 33 of the ring are located facing the orifices 77 , 78 of the ducts 17, 18 included in the axle 5, so as to effect the transfer of liquid into or out of the target, at a position where the walls of the ring face the orifices 77, 78 of these ducts 17, 18 and where the ports 33 of the ring are located opposite the space between the two O-rings 31 and 32, thereby blocking the passage of the liquid so as to retain the liquid in the target.

The process of charging the liquid in the target is carried out as follows:

the injector 25 is positioned on the ports 33 of the ring 29;

a first mechanical device slides the ring 29 so that the ports 33 of the ring are facing the orifices 77, 78 of the conduits 17 and 18;

the three-way valve 44 connects a syringe 43 to the reservoir 28 comprising the radioisotope precursor; - A second mechanical device actuates the piston of the syringe 43 to collect the precursor;

the same three-way valve 44 changes position so as to connect the syringe 43 to the channel A of said six-way valve 41;

the six-way valve 41 is actuated so as to connect the track A to the track

B and the D route to the E route;

said second mechanical device actuating the syringe 43 injects the radioisotope precursor into the target 1;

the overflow of liquid injected into the target 1 is sent to a container 42;

said first mechanical device slides the ring 29 on the axle so that the ports 33 of the ring are offset relative to the orifices 77 and 78 of the conduits 17, 18 to maintain the liquid inside the bedroom 4;

the injector 25 is disconnected from the ports of the ring.

The loading process carried out, the six-way injection valve 45 is actuated so that no channel is in communication with another. The motor 6 is then turned on and makes the target 1 turn in rotation on itself. Cooling fluids are sent to the target and then comes into operation the particle accelerator producing a beam for example protons radiating the target in rotation.

After irradiation of the precursor of radioisotopes contained in the target, the process of discharging the liquid is effected by reconnecting the injector 25 to the ring 29. The ports 33 of the ring 29 are then repositioned facing the orifices 77 , 78 ducts 17, 18. The six-way valve 45 is actuated so that the track B is in communication with the track C connected to the container 27, and so that the channel E is in communication with the channel F connected to a tank of inert gas, for example helium. The gas cylinder is then opened to push the irradiated liquid contained in the target 1 to the container 27. The configuration of the device according to the present invention allows an effective cooling of the radioisotope precursor liquid 4 in said target 1. Indeed, several effects contribute to the cooling of the liquid:

cooling from the front and rear of the target;

the fact that only a part situated at the periphery of the target is exposed to the beam;

the rotation of the target periodically exposing a portion of the periphery of the target to the beam, each part of the periphery of the target then being directly cooled after passing through the axis of the beam; and the centrifugal force which continuously repels colder, and therefore denser, liquid from the center of said target towards the periphery thereof.

A second embodiment of the shutter 29 comprises solenoid valves 37, 38 located at the orifices 77, 78 of the ducts 17, 18 included in the axle 5, the solenoid valves into which the so-called ducts are inserted. 67, 68 exiting the loading-unloading device 50. Each duct 67, 68 comprises a plug 47, 48 inserted into a complementary part 57, 58 of the solenoid valve located at the level of the axle 5 creating a contact allowing the opening of the solenoid valve passing the liquid, as shown on the fig. 12. The fij. 9 shows the device during the loading or unloading step, where the ducts 67, 68 leaving the loading-unloading device 50 are connected to the electro-valves 37, 38.

[0058] Figs. 10 and 11 show the device of the present invention during the irradiation step, where said plugs 47, 48 are disconnected from their complementary part 57, 58, the absence of contact thus causing the closing of the solenoid valves 37, 38 preventing the passage of liquid and keeping it inside the target. The solenoid valves being closed, the motor 6 can be engaged so as to rotate said target 1 during the irradiation step.

An alternative device of the present invention comprises a chamber 4 shown on fig. 13 inside which is placed a drive means 26 of the liquid, for example a plate whose plane is perpendicular to the surface of the chamber 10 exposed to the beam. Advantageously, said plate 26 comprises one or more holes allowing the passage of the liquid from a first volume included in said chamber to a second volume in the same chamber, the first and second volumes being separated by said plate 26. The presence of said plate 26 in said chamber allows a better entrainment of the liquid included in the chamber so as to prevent liquid zones from being more irradiated than others. Indeed, because of the viscosity of the liquid and the frictional forces between the liquid and the walls of the chamber, one could have a liquid region located towards the inside of the chamber which would remain static. Differences in entrainment of the liquid between several internal zones of the chamber may have the consequence of having zones of liquids which have been longer irradiated and thus more heated than others, hence a possible problem of optimum cooling of the liquid to the liquid. inside the room. The said plate 26 placed perpendicular to the irradiated surface 10 of the target could allow better entrainment of the liquid and better cooling.

Claims

Device (100) for the production of radioisotopes by the irradiation of a radioisotope precursor using a particle beam (3), said device comprising:

a target (1) comprising a chamber (4) intended to receive a liquid comprising a radioisotope precursor, said target (1) comprising orifices (7,8) intended for the introduction of said liquid into said chamber (4 ) or the evacuation of said liquid out of said chamber (4);

means for cooling said target (1); said device being characterized in that it comprises

a wheel (40) on which said target (1) is mounted, and;

a motor (6) capable of rotating said wheel (40);

and that said target (1) is mounted on a plane formed by the periphery of said wheel (40), so that when said wheel (40) rotates, the region of impact of the beam (3) on target (1) changes continuously.

Device according to claim 1 characterized in that it comprises an axle (5) supporting said wheel (40), the axle (5) being parallel to the axis of said beam (3).

Device according to claim 2 characterized in that it comprises a loading-unloading device (50) of said liquid allowing the introduction of said liquid into said chamber (4) or the evacuation of said liquid out of said chamber (4) , conduits (67, 68) exiting the loading-unloading device (50) being coupled to other conduits (17, 18) connected to said orifices (7, 8) of said target (1) and included in spokes (35) of said wheel (40) as well as in said axle (5).

Device according to claim 3 characterized in that it comprises a shutter (29) located on said axle (5), the shutter (29) being articulable between a first position allowing the liquid to pass so as to make it enter the target (1) or exit the target (1) and a second position blocking the passage of the liquid so as to maintain it inside said target (1).

Device according to claim 4 comprising an injector (25) comprising the ends of said conduits (67, 68) exiting the liquid loading-unloading device (50), said injector (25) being connectable to the conduits (17,18) connected to said orifices (7,

8) of said target (1).

Device according to any one of the preceding claims characterized in that said target (1) is circular in shape.

Device according to any one of the preceding claims characterized in that it comprises a collimator (14) located in the axis of said beam (3), and whose opening area is less than the area of the surface of the target (1), so that a part of said target (1) is irradiated by the beam (3), thus minimizing heating of said target (1).

Device according to any one of the preceding claims characterized in that said target (1) comprises:

a first sheet (9) held against spokes (35) of said wheel (40);

a spacer (24) fixed on said wheel (40), and now said first sheet (9);

a second sheet (10) separated from said first sheet

(9) by said spacer (24);

means (23) for fixing said second sheet (10) against said spacer (24) and; sealing means (41) located on either side of said sheets (9, 10);

forming said chamber (4).

Device according to any one of the claims characterized in that said orifices (7,8) of said chamber (4) are located face to face in said spacer (24).

10. Device according to any one of the preceding claims characterized in that the cooling means (11, 13) of said target (1) comprise:

- a first cavity (13) located at the front of the target (1) between it and said collimator (14), said first cavity (13) through which a gas flow passes;

- a second cavity (11) located at the rear of the target (1) and crossed by said axle (5), said second cavity (11) through which a flow of cooling fluid passes;

- sealing means (19, 22) arranged on parts of the device capable of rotating against other static parts of the device which also comprising sealing means (20, 21) so that the sealing of each cavity (11, 13) is ensured;

said first and second cavities (11, 13) comprising said target (1).

11. Device according to claim 10 characterized in that said second cavity (11) comprises an inlet (12) of cooling fluid facing said region of impact of the beam on said target (1).

12. Device according to one of the preceding claims wherein said chamber (4) comprises means (26) for driving the liquid between said first and second sheets (9, 10) of said chamber (4).

13. Method for producing radioisotopes comprising the following steps: filling a chamber (4) of a target (1) with a liquid comprising a radioisotope precursor;

rotation of said target (1) and irradiation of said target (1), so that the region of impact of the beam (3) on said target (1) changes continuously, so that heating of the target (1) ) by the irradiation of the beam (3) is minimized;

stopping the irradiation and rotation of said target (1);

emptying of said target (1).

14. Method for producing radioisotopes according to claim 13 using a device according to any one of claims 1 to 12.

15. Method for producing radioisotopes according to claim 14 comprising the following steps:

(i) putting said loading-unloading device (50) into communication with the orifices (7, 8) of said chamber

(4);

(ii) loading the radioisotope precursor liquid into said chamber (4);

(iii) closing the communication of said loading-unloading device (50) with the orifices (77, 78) of said conduits (17, 18) located on the external surface of the axle

(5);

(iv) actuation of the motor (6) rotating the chamber (4) around an axis of rotation coincident with the axis of the axle (5) of the device;

(v) irradiation, by a beam (3) produced by a particle accelerator (2), of said chamber (4) cooled by a cooling device;

(vi) stopping the irradiation and the engine (6); putting said loading-unloading device (50) into communication with the orifices (7, 8) of said chamber (4);

unloading the irradiated liquid comprising the radioisotope of interest to a container (27).