Patent Application
20060014997
The invention relates to a device for radiation treatment of proliferative tissue surrounding a cavity in an animal body comprising:
The invention also relates to a method for controlling the condition of a radiation treatment being performed on proliferative tissue surrounding a cavity in an animal body, wherein for performing said radiation treatment an inflatable balloon system having a balloon wall is placed in said cavity, said balloon system is inflated with a pressurized medium, and at least one energy emitting source is placed within said cavity for performing said radiation treatment.
Such device is for example known from European patent application no. 1 402 922 A1 in the name of the present applicant, Nucletron B. V.
The one major advance that has had the greatest influence on the re-emergence of brachytherapy in recent years has been the introduction of remote afterloaders. A remote afterloader (or afterloading apparatus) enables the insertion of energy emitting sources through a catheter tube towards a specific location within a patient's body without the risk of exposing unnecessary radiation doses to the radiotherapy staff.
In addition to this development there has been a trend in the past few years towards the use of high dose rate (HDR) energy emitting sources in brachytherapy applications in which much higher activity sources are inserted or implanted within a patient's body for much shorter periods of treatment time.
These HDR sources are sometimes inserted in a single fraction or more often with a few separate insertions.
Together with the increased interest for this treatment modality more sophisticated applicators have been developed and the classical plastic or metal applicators are replaced step by step with combined applicator-balloon or balloon-based devices. These devices are surrounded by an inflatable balloon system, which balloon system is introduced with the applicator into a natural body cavity or where a cancer tumour has been excised by means of surgery.
Following surgical removal of a tumour, the inflatable balloon system is introduced into the cavity caused by the removal of the tumour. After inflating the balloon system one or more energy emitting sources are introduced at one or more locations within the body cavity in order to treat the tissue surrounding said surgically excised tumour with radiation in order to kill any cancer cells that may be present in the margins surrounding the excised tumour.
An inflatable balloon system allows an immobilization of the region within the cavity the patient's body to be treated by radiation, or a centering of the treatment region, or it provides a displacement of organs at risk away from the treatment region to be irradiated.
From the above it will be clear that a correct positioning of the applicator and the reproducibility of the position of the applicator is important and will have a direct influence on the clinical outcome. The dose rate emitted by the energy emitting source inserted within the body cavity and present at a certain point will be determined from the distance of the source to the tissue and this distance is dependent from the inflation or deflation status of the balloon system applicator.
As the balloon system applicator is inserted inside a body cavity a visual control of the inflation status is impossible. The use of additional imaging techniques, like ultrasound or X-ray imaging, constitutes an extra discomforting burden for the patient and cannot be maintained during the radiation treatment when radiation is being delivered to the treatment region.
As result, with the inflatable balloon system devices presently known the risk of any misadministration of a radiation dose to the patient is very high and can not be controlled or corrected.
It is therefor an object of the invention to provide a device for radiation treatment of proliferative tissue surrounding a cavity in an animal patient body according to the above preamble capable in monitoring the real, actual functional status of the inflated balloon system present inside said body cavity, especially when said device is utilized with an after loading apparatus.
The device is according to the invention characterized in that said device comprises monitoring means for monitoring the inflation status of the inflatable balloon system. Hence with the device according to the invention the actual inflation status of the inflated balloon system can be determined, providing accurate information about the operational conditions of the device during radiation treatments being performed in an animal body. Any malfunction can be easily detected thereby obviating the risk of any misadministration of a radiation dose to the patient.
More in particular said monitoring means are according to the invention arranged in comparing the actual inflation status being monitored with a pre-determined desired inflation status of the inflatable balloon system and in operating the device based on control signals generated as a result of said inflation status comparison. Hence these features allow any correction of any unfavourable operational conditions, which may adversely affect the radiation treatment being performed in the cavity of said animal body.
Especially in one preferred embodiment said radiation delivering means are arranged in retracting said at least one energy emitting source from said cavity based on control signals generated by said monitoring means as a result of said inflation status comparison. This safe measure prevents an uncontrolled radiation dose being administered to the animal body (patient) during a malfunction of the balloon system.
In another preferred embodiment said at least one energy emitting source is an activatable energy emitting source and wherein said radiation delivering means are arranged in de-activating said at least one energy emitting source in said cavity based on control signals generated by said monitoring means as a result of said inflation status comparison. Therefor the device according to the invention is not only suitable for energy emitting sources who emit radioactive radiation according to the principle of natural radioactive decay, but also for energy emitting sources who are to be activated in order to emit radiation, like an X-ray emitter, or laser source, etc.
In another preferred embodiment said inflation means are arranged in inflating and/or deflating the balloon system based on control signals generated by said monitoring means as a result of said inflation status comparison. This feature allows the inflation status of the balloon system to be corrected within a safety pressure bandwidth.
In this latter embodiment said monitoring means may comprise at least one pressure sensor for generating pressure data corresponding to the actual pressure of said pressurized medium in said inflated balloon system, said pressure data being used for said inflation status comparison.
More in particular the monitoring means are arranged in comparing said pressure data with a pre-determined pressure bandwidth and in operating the device based on control signals generated as a result of said pressure comparison.
In preferred embodiments said at least one pressure sensor can be positioned inside or outside the balloon system,
In another advantageous embodiment of the device according to the invention said monitoring means comprise an imaging device for generating image data corresponding to the actual balloon wall contour of the inflated balloon system, said image data being used for said inflation status comparison.
The monitoring means are thereby arranged in comparing said image data with a pre-determined balloon wall contour and in operating the device based on control signals generated as a result of said contour comparison.
Hence with the use of image data instead of pressure data the actual inflation contour of the balloon system inside the cavity in the patient's body is monitored and used for correcting the device in the event that any malfunction or deviation from the optimal operational conditions are detected.
In order to obtain more accurate information concerning the actual operational conditions of the device and the balloon system in a specific embodiment the monitoring means are arranged in converting said image data obtained with said imaging device into a three-dimensional image of the actual balloon wall contour of the inflated balloon system.
Said imaging device may be constructed as ultrasound imaging probe or as a video camera, which imaging devices are in a preferred embodiment insertable inside the balloon system in order to obtain more actual local information allowing a more accurate and prompt correction of the operational status of the device in case of a malfunction or deviation.
In yet another advantageous embodiment said monitoring means comprises at least one radiation dose sensor for generating radiation data corresponding to measured radiation emitted by said at least one energy emitting source being placed within said cavity and corresponding to the actual distance between said at least one radiation dose sensor and said at least one energy emitting source within said cavity, said radiation data being used for said inflation status comparison.
More in particular the monitoring means are arranged in comparing said radiation data with a pre-determined desired distance between said at least one radiation dose sensor and said at least one energy emitting source within said cavity and in operating the device based on control signals generated as a result of said radiation comparison.
The radiation data being generated by the radiation sensor is a measure of the actual distance between the sensor connected to the balloon system and the energy emitting source placed within the cavity and which source emits the radiation that is detected with the radiation sensor. The radiation intensity of emitted radiation decreases with the distance according to pre-determined rules. By comparing the actual distance as obtained from the measured radiation with a pre-determined desired distance accurate information can be obtained about the actual inflation status of the balloon system.
In the event the balloon system becomes deflated due to a malfunction the radiation being detected by the sensor will reveal a shorter or decreased distance between the sensor and the source emitting said radiation. Also in the event of an over-inflating of the balloon system the radiation being detected by the sensor will reveal a longer or increased distance. In both situations the device is controlled in order to correct for these malfunctions or deviations from the optimal operational conditions.
Preferably said at least one radiation sensor is connected to the inner or outer wall of the balloon system.
Furthermore the inflation means may comprise a piston-cylinder combination having a cylinder and a piston movable accommodated in said cylinder. More in particular said inflation means comprise piston drive means for displacing said piston within said cylinder based on control signals generated by said monitoring means.
Furthermore a medium conduct is present interconnecting the cylinder with the inflatable balloon, whereby an additional feature consists of a supply vessel for said medium being present in said medium conduct.
More in particular a first valve is accommodated in said medium conduct between said supply vessel and said piston-cylinder combination, whereas a second valve is accommodated in said medium conduct between said piston-cylinder combination and said inflatable balloon system. As in a specific embodiment both said first and said second valve can be actuated by said monitoring means the inflation status of the balloon system can be accurately controlled and any malfunction can be detected and direct specific measures can be performed avoiding the misadministration of a radiation dose to the patient.
In another specific embodiment said radiation delivering means are constructed as an after loading apparatus.
Likewise the method according to the invention is characterized by the step of monitoring the inflation status of the inflatable balloon system before and during the performance of said radiation treatment. With the method according to the invention accurate information about the operational conditions of the radiation treatment being performed in an animal body can be obtained. Any malfunction can be easily detected thereby obviating the risk of any misadministration of a radiation dose to the patient.
In an further aspect the method according to the invention further characterized by the steps of comparing the actual inflation status being monitored with a pre-determined desired inflation status of the inflatable balloon system and of controlling the condition of the performance of the radiation treatment based on control signals generated as a result of said inflation status comparison.
Further implementations of the method according to invention comprises the steps of retracting said at least one energy emitting source from said cavity based on control signals generated as a result of said inflation status comparison or of inflating and/or deflating the balloon system based on control signals generated as a result of said inflation status comparison.
Other aspects of the method according to the invention are described in the claims.
The invention will now be described with reference to a drawing, which shows in:
a-4b a fourth embodiment of a device according to the invention.
For the sake of clarity corresponding parts of the embodiments shown in the enclosed drawings are depicted with identical reference numerals.
To this end an applicator 10 is introduced into the cavity 2, which device 10 comprises a supportive probe 11 having an inflatable balloon system 12 connected to a distal end 11a of said supportive probe 11. Once the deflated balloon system 12 has been introduced inside the cavity 2, the balloon system 12 is inflated by suitable inflation means by injecting a pressurized medium 25 (for example a fluid) via a passageway 14 in the supportive probe 11 towards the distensible reservoir formed by the balloon system 12.
Said pressurized medium 25 could be a fluid or a gaseous medium or a liquid containing radioactive particles. Also other type of pressurized media, radioactive or not, can be utilized.
In addition, the supportive probe 11 is provided with a guidance channel through which a flexible catheter tube 13 is guidable until it extends with its distal end 13b within the cavity 2. The catheter tube 13 is connected with its proximal end 13a with radiation delivery means 20, here a remote afterloader apparatus 20 for performing radiation therapy treatments of the cancer tissue surrounding the cavity 2. The afterloader apparatus 20 contains a radiation shielded compartment 20a, in which compartment an energy emitting source 22 is accommodated.
The energy emitting source 22 is attached to a distal end 21b of a source wire 21, which source wire can be advanced through the hollow catheter tube 13 by means of wire drive means 20b. The energy emitting source 22 can be advanced from said radiation shielded compartment 20a through the hollow catheter tube 13 towards a desired location within the cavity 2.
The positioning of the energy emitting source 22 at different locations within its hollow catheter tube 13 and in the cavity 2 gives more possibilities for performing a radiation therapy treatment session. The total dose distribution of the tissue to be treated will be conformal with the volume of the tumour tissue surrounding the cavity 2 by optimizing the dwell times for the different positions within the cavity 2 of the energy emitting source 22. Moreover the guidance of the energy emitting source 22 through the hollow catheter tube 13 within the cavity 2 allows a temporarily insertion of the source 22 in the reproducible manner at different locations.
With the use of an afterloader device 20 it is possible to use the device 10 according to the invention to perform radiation therapy treatment sessions with so called High Dose Rate (HDR) or Pulse Dose Rate (PDR) in emitting sources, which requires special and save handling prior to each treatment session. These HDR or PDR sources are characterised by a high radiation intensity profile and are thus for safety reasons accommodated in a radiation shielded compartment 20a within the afterloader 12. A radiation therapy treatment session with such high intensity energy emitting sources requires specific proceedings concerning handling a storage of these sources.
To this end in a proper operation of the inflatable balloon system 12 is necessary in order to avoid any misadministration of a radiation dose to the patient. The device 10 according to the invention comprises monitory means for monitoring the inflation status of the inflatable balloon system 12. More particular said monitoring means 16 uses at least one pressure sensor 17 which is accommodated in a medium conduct 15. The pressure sensor 17 senses the actual pressure of the pressurized medium 25 inside the inflate balloon system 12. Said sensor 17 generates a pressure signal 17a conformal with the pressure being sensed and said pressure signal 17a is fed to the monitoring means 16.
According to the invention said monitoring means 16 are arranged in comparing said pressure being sensed by the pressure sensor 17 with a predetermined pressure bandwidth. Said predetermined pressure bandwidth describes a range of pressures of said pressurized medium 25 under which pressure circumstances the device 10 according to the invention can be operated under normal conditions.
In the event a significant deviation of the pressure being sensed by said pressure sensor 17 and the predetermined pressure bandwidth is detected the monitoring means 12 are arranged in controlling the device 10 based on control signals generated as a result of said pressure comparison.
In other words, in the event the pressure being sensed by the pressure sensor 17 lies outside the predetermined pressure bandwidth the monitoring means 16 will generate suitable control signals based on which the device 10 will be controlled. In a first control step a control signal 23a will be generated by the monitoring means 16 and fed to the afterloader apparatus 20 in order to actuate the wire drive means 20b. For example in the event that the pressure of the pressurized medium 25 inside the balloon system 12 becomes significantly low (for example due to a leakage) the control signal 23a generated by the monitoring means 16 will result in an immediate retraction of the source wire 21 and the emitting source 22 by the wire drive means 20b.
In another embodiment (not depicted) the energy emitting source 22 is an activatable source, like an X-ray emitting source or laser device and in the event of a malfunction the device according to the invention (and in particular the afterloader 20) is arranged in de-activating the energy emitting source within the cavity 2.
These safe measures prevent an uncontrolled radiation dose being administered to the cancer tumour surrounding the cavity 2 inside the animal body 1 during a malfunction (leakage) of the balloon system 2.
In an other control step a control signal 23b generated by the monitoring means 16 will be fed to the inflation means 30 in order to actuate the inflation means such that the balloon system 12 is inflated or deflated until the medium pressure of the medium 25 present in the balloon system 12 will fall within the predetermined pressure bandwidth corresponding with the optimal operation conditions.
A specific embodiment of the inflation means is here described by way of example. However it should be note that also other types of inflation means are suitable and can be implemented in the device according to the invention. The inflation means 30 in this example comprise a piston-cylinder combination 30 having a cylinder 31 and a piston 32 which is movable accommodated in said cylinder 31. The piston-cylinder combination 30 is provided with piston drive means 35 for displacing said piston 32 within the cylinder 31. To this end the piston 32 is mounted on a piston rod 33. The displacement of the piston 32 inside the cylinder 31 by the piston drive means 35 takes place based on control signals generated by the monitoring means 16.
The piston-cylinder combination 30 is provided with an cylinder chamber 34 in which the amount of medium 25 for inflating the balloon system 12 of the device 10 according to the invention is accommodated. The piston-cylinder combination 30 is connected with the passage way 14 and the inflatable balloon system 12 by means of a medium conduct 15. In said medium conduct 15 a supply vessel 19 is accommodated which is suited for storing a certain amount of medium 25. The storage vessel 19 is closed by means of a first valve 18a which is accommodated in the medium conduct 15 between the piston-cylinder combination 30 and the storage vessel 19. Between the piston-cylinder combination 30 and the passage way 14/the balloon system 12 a second valve 18b is accommodated in the medium conduct 15.
Both valves 18a and 18b can be actuated by the monitoring means 16 with the use of suitable control signals. For example in the event that the balloon system 12 needs to be inflated (for example as a result of a possible decrease in the operational pressure inside the balloon system 12) the monitoring means 16 generate suitable control signals based on the comparison between the actual sensed low pressure inside the balloon system 12 and the predetermined optimal pressure bandwidth. These control signals will effect a closure of the first valve 18a and an opening of the second valve 18b. A likewise actuation of the piston drive means 35 will be effected, such that medium 25 present in the cylinder chamber 34 is pushed through the conduct 15 through the open second valve 18b and the passage way 14 towards the balloon system 12, thereby inflating the balloon system 12.
Likewise, in the event that a too high pressure inside the balloon system is sensed suitable control signals generated by the monitoring means 16 will actuate the piston drive means 35 such that the piston 32 is retracted inside the cylinder 31 thereby redrawing or deflating medium 25 out of the balloon system 12 and the passage way 14 towards the cylinder chamber 34. With this control step the actual pressure inside the balloon system 12 will decrease.
In
In
The imaging device 17″ in the embodiment as disclosed in
In a first specific embodiment of the device as disclosed in
In other functional embodiment the imaging device 17″ is advanced using the signal cable 42 by the drive means 41 in a step wise manner through the insertion catheter 40 through the balloon system 12 thereby generating image data in sequential measurements or “sweeps” of the actual balloon wall contour of the balloon system 12.
The image data representing the actual balloon wall contour of the balloon system 12 is fed via the signal cable 42 and 17a towards the monitoring means 16, wherein said image data is converted into a three dimensional balloon wall contour indicated with reference numeral 12′.
According to the method of the invention the monitoring means 16 are arranged in comparing said three dimensional balloon wall contour 12′ with a pre-determined balloon wall contour as depicted as a dashed circle and reference numeral 12″. Based on this contour comparison using the image data obtained with the imaging device 17″ any deviations or malfunctions of the balloon wall 12 are quickly detected and appropriate control can be performed in order to correct for the malfunctions being detected.
Likewise the imaging device 17″ can be positioned outside the cavity 2 and the patient's body 1 in order to generate an image of the cavity 2 using suitable imaging techniques.
The imaging device 17″ (placed inside or outside the cavity 2 in the patient's body 1) can be an ultrasound imaging probe or a video camera. Especially an ultrasound imaging probe or a video camera can be constructed in small dimensions in order to allow an insertion through the insertion catheter 40 until within the inflated balloon system 12.
In
As the radiation sensor is connected to the inner or outer wall of the balloon system 12 the distance between the sensor 40 and the energy emitting source 22 being placed within the cavity 2 is dependent from the inflation status of the balloon system.
In
The radiation data generated by the sensor 40 is fed via the signal line 17a towards the monitoring means 16, which operate in a similar way as described in relation to the embodiments of
However,
Also in the event of an over-inflating of the balloon system 12 the radiation 22a being detected by the sensor 40 will reveal a longer or increased distance and also a suitable control of the device is performed by the monitoring means 16 in order to correct for this malfunction.
It will be appreciated that with the device according to the invention a more safe operation of a device according to the invention with the use of an afterloader apparatus is obtained wherein possible hazardous operational conditions are avoided as with a continuous monitoring of the actual pressure inside the balloon system 12 possible changes in the operational pressure will be sensed immediately and a suitable control of the device 10 according to the invention is performed by the monitoring means 16 in order to correct for the change in the operational status of the device (balloon system 12).
| Number | Date | Country | Kind |
|---|---|---|---|
| 04077066.1 | Jul 2004 | EP | regional |
