JP2001190700A - Apparatus for controlling x-ray dose - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus for the controlled supply of ionizing radiation to a part to be treated. SOLUTION: The apparatus includes an ionizing radiation generation source 4 installed at the final end of a slender member 6 and also has a control unit 12 to control the movement of the radiation source 4 at a part to be treated through a drive unit 21. The method of this invention includes the regulation of radiation dose at the part to be treated by controlling the movement of the radiation source.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a system and apparatus for delivering a controlled dose of X-rays to a treatment site in a human or animal body.

[0002]

BACKGROUND OF THE INVENTION For some medical treatment situations,
It is necessary to expose certain lesions to radiation so that the affected area can be treated.

[0003] As one example, traditionally, a stenotic coronary artery is used for balloon dilatation surgery, ie, percutaneous transluminal coronary angioplasty (Percutaneous Transl).
uminal Coronary Angioplas
ty) (PTCA). A small balloon at the tip of a plastic catheter is inserted into the femoral artery, guided to a stenotic site in the blood vessel, and inflated. When the stenosis is pushed out by the balloon, the artery is widened to its normal inner diameter. To further improve the treatment, a so-called stent is usually placed at the stenosis. However, in about one third of patients, restenosis will still occur after PTCA is performed.

One means of slowing the rate of restenosis is to partially treat the vessel wall with x-rays, gamma rays or beta rays in combination with PCTA. The exact mechanism by which radiation suppresses restenosis is still poorly understood. However, in some attempts it has been shown that radiation doses as high as about 10 to 50 Gy from gamma and beta (radiation) sources introduced by catheters slow the rate of restenosis.

[0005] Generally, a radiation source in the form of a radionuclide is used, for example to supply the required radiation source. If the lesion has different areas and thicknesses in various directions inside the blood vessel, it is extremely difficult to provide a localized radiation dose at hand. Prior art methods and apparatus are described, for example, in US Pat. No. 5,899,882.
On the basis of the provision of a plurality of radioisotopes (nuclides) arranged in rows as disclosed in the Novostc Corp. The main disadvantage of this method is that the length is not applicable in the actual case or at least only in a barely applicable way. For example, if a radiological device is provided with an isotope 4 mm or longer in length and the device is used to irradiate a 3 mm long lesion, healthy tissue may be undesirably exposed to radiation. I have to say that it will be.

In order to achieve a rotationally symmetric and uniform irradiation,
Various mechanical methods and means have been used in the prior art. These prior art means are provided for mechanically centering the radiation source within the blood vessel, for example by means of suitable spacer means.

[0007] Applicants' US patent application Ser. No. 08 / 805,296 (WO 98/367), which is hereby incorporated by reference in its entirety.
96 (corresponding to 96), for example, in the form of a radionuclide in the form of a pair of plates, a sealed microcavity formed in one of the pair of plates, at least one of which comprises: A pair of electrodes in the form of a cathode and an anode disposed in a microcavity, the other being disposed on the other plate, wherein the anode is at least partially made of a relatively high atomic weight metal; A small radiation source for ionizing electromagnetic radiation is disclosed, including a conductive lead connected to the cathode and anode. Further, US Provisional Application 60/13, owned by the applicant.
7,478 (Swedish patent application 9902118-
(Corresponding to No. 0), X-ray sources that can be turned on and off electronically are also suggested.

[0008] Another device is a balloon catheter for inflation, but based on a balloon catheter in which the balloon is filled with a radioactive liquid passing through the lumen of the catheter. This device has the disadvantage that there is a risk that the radioactive liquid may unexpectedly come into the surrounding atmosphere.

[0009] Yet another method is to cover the balloon of the balloon catheter device with a radioactive coating. As already mentioned, the problem with prior art devices is that
The delivered dose is divided spatially, i.e., the individual radiation sources in U.S. Pat. No. 5,899,882 (Novoste) are essentially point sources and are placed on a guide wire to cover a large area. In view of the fact that multiple point light sources must be provided, it is difficult to control spatially. This is difficult from a manufacturing point of view, and the assembly of some x-ray sources is relatively bulky when provided with a large number of radiation sources; Makes it difficult to manipulate the guidewire inside the interior.

[0010] Also, too much radiation kills cells, while too little radiation provides the correct amount of radiation in that cancer cells and other cells can be grown without actually achieving the desired therapeutic effect. Supplying may be important.

[0011]

Accordingly, it is an object of the present invention to provide ionizing radiation (e.g., X-ray) at a treatment location where control of the dose over a selected treatment area can be significantly improved.
Line). In particular, the lesion to be treated should receive a known and controlled radiation dose. Healthy tissues should not receive significant radiation doses. The term "controlled" means exposure to a known amount of radiation at a given depth, regardless of the thickness of the lesion.

[0012]

SUMMARY OF THE INVENTION In order to solve this problem, the present invention provides a method of treating a radiation source by enabling the operation of a radiation source to control the amount of radiation delivered and the dose with respect to the location where it is delivered. Means can be provided for changing the supply position at a location. In particular, the present invention is directed to adjusting its position in a vessel longitudinally when radiation is to be provided over a larger area than is covered by a radiation lobe from an individual radiation source. Enable. Further, the present invention allows for rotation of the radiation source inside the blood vessel. The above object is achieved by a device as claimed in claim 1.

In yet another aspect, the present invention is directed to a method of providing a controlled dose of ionizing radiation to a lesion at a treatment site. This method is defined in claim 10.

Embodiments that specifically address various issues include:
Stipulated in each dependent claim.

[0015]

DETAILED DESCRIPTION OF THE INVENTION First, some PTCA treatments are used.
This will be described in more detail. As already mentioned, the balloon category
Ethers are used to dilate stenotic blood vessels.
In this treatment method, the stenosis is located at 1a (PT
1B shows a stenosis state before the CA treatment) and FIG.
(After PTCA treatment)
Is forced out of. However, this treatment
Has the effect of spreading and sometimes breaking blood vessel tissue
You. This often causes wound growth and, therefore,
Restenosis often occurs after PTCA, ie, stainless steel.
Tissue grows inward again, even when inserted
Will. The mechanism of restenosis is well understood, as indicated above.
Not understood. However, for stenosis sites
The effect of the radiation described is the tissue adjacent to the stenosis,
The vessel wall VW and other tissues outside the vessel may be damaged.
It is believed to be. This allows
Long speed is reduced. Therefore, to damage the tissue
Radiation first penetrates the stenosis (solidified platelets)
And then continue to produce the desired effect.
And will remain strong. One method is for radiation to cross the lesion.
A certain distance, blood as indicated by the dashed line A
A certain depth from the boundary between the platelet and the blood vessel or other tissue
D ₁Only to penetrate into the tissue behind it
It is to be. Another method is to use a dash-dot line B
Constant depth D from the center C of the blood vessel indicated by_TwoUntil
It may need to penetrate. Selected method
Depends on the control unit is correspondingly programmed
But once the principle is understood, the book
Adopt any method without departing from the idea of the invention
Can be

The device according to the invention will be described below,
FIG. For example, a small X-ray generator 4 (in the embodiment shown, based on tip technology) can be attached to a simple wire 6 lying inside the catheter 8 (however, the invention is not limited to this). For the purposes of this general concept, the source can be of any type, such as a conventionally used radioisotope or an electrically activated X-ray radiation source). Wire 6 is
It can then be moved back and forth within the catheter lumen, as indicated by the arrows. This movement can be done manually, but according to the invention, for example, a motor-driven gearing (not shown) is provided which allows a pre-programmed back and forth movement inside the catheter 8. This is extremely useful when it is desirable to provide radiation over a relatively elongated affected area, which is difficult, if not impossible, to provide a radiation source that covers the entire affected area. In yet another embodiment, means for rotating the radiation source may be provided. Spiral movement will be achieved in combination with longitudinal movement.

In yet another embodiment, the catheter is designed to seal the interior, thereby protecting the patient from exposure to the wire. Thanks to the sealed catheter, there is no need for sterilization of the wires and radiation sources, so they can be made as reusable parts, and when sterilization is not required, the operation is of course much easier. There will be.

The entire wire, with the radiation source attached at the end, can be provided on a spool or cylinder 10 arranged inside the control unit 12. This provides adequate protection for relatively sensitive devices. An X-ray detector 14 can be provided inside the control unit adjacent to the spool, so that calibration or function checks can be performed in the control unit. This requires adequate radiation shielding surrounding the location of the source.

Preferably, the radiation source and / or the distal portion of the catheter include several pieces of radiolucent material so that the radiation source can be properly positioned when the catheter is inserted into a blood vessel. 16 and 18 are provided.

If the wire 6 to which the radiation source is attached is made of metal, this wire can be used as a conductor for providing an operating voltage at the tip. A second electrical conductor may be provided as a single lead 20 that runs parallel to the wire and is properly attached. Coaxial structures are also conceivable in which an insulator is provided around the core and the second conductor is provided as a concentric layer of conductive material on the insulator.

The standard method of positioning a catheter, ie, manipulating the catheter to a selected treatment site within a patient's body, involves treating a guidewire that is flexible enough to be easily manipulated. Is the first insertion into the place where it is made. The catheter to be used is shown in FIG.
, The radiation source 4 will have a small lumen 22 sealed from the rest of the interior of the catheter 8 to be placed. Catheter end 28
Has a first opening 24 for accessing said lumen.
A second opening 26 provided in the side wall of the catheter;
Is provided. Therefore, the catheter 8 is
Can be passed over the (guide) wire 6 by inserting the proximal end of the (guide) wire through and passing it through the lumen 22 and out of the opening 26. The catheter can then be delivered along the guidewire to the desired location.

In the device disclosed in FIG. 2, the radiation source is shown as a small chip 4 from which the radiation is directed in the direction indicated by the arrow hv or in a non-symmetrical manner in the other direction. Will be emitted at a higher intensity than the direction of

Another design principle for a radiation source is shown in FIG. Here, an accelerating voltage is applied in the longitudinal direction of the radiation source, and will therefore produce radiation (at least in theory) radially to an equal extent throughout the surrounding environment.

As already indicated, the operation of the device relies on information about the lesion to be treated which can be obtained. Typically, one or more of the following methods are used. 1) X-ray examination; this will form information about the length of the lesion or stenosis in the longitudinal direction and the local anatomy of the thicker and thinner parts. Of course, the exact placement of the stenosis can also be determined.

2) (Intravenous) ultrasonography; this method can provide information about the cross-sectional area of a lateral stenosis in a blood vessel. By forming and adding an “image” of the cross section of the stenosis, an image having a good spatial distribution of the stenosis can be obtained. By this method, composite data can also be obtained.

3) Information on the concentration of the complex, ie calcium (solidified platelets), can also be obtained by NMR techniques. The higher the concentration of Ca, the more
The absorption is higher and the required irradiation time is longer.

Therefore, it is possible to obtain quantified information about the location of the stenosis, its topography and its composition. This information is sent into the control unit of the device according to the invention, which, based on the information, determines the longitudinal sweep rate of the radiation source inside the blood vessel,
At any time, an appropriate treatment program will be calculated for changes in radiation intensity during a sweep to apply to a particular topography, and for the concentration of solidified platelets in the lesion.

Next, various functions of the present apparatus will be described in more detail. As noted above, in one embodiment, the longitudinal translation employs a spool or cylinder that allows the (guide) wire with the radiation source attached to it to be unwound or wound. Achieved by: However, in a preferred embodiment, it is desirable to provide a pair of drive rollers 21 between which a (guide) wire 6 is passed to form a "pinch" (see FIG. 2). The rotation of the roller is synchronized with the rotation of the spool 10. In this way and by coupling the unit that drives the spool 10 (eg, the electric motor 22) to the control unit, the movement of the guidewire is controlled with respect to operating speed and range. The operating range is controlled in relation to the radiation intensity so that the desired dose is delivered to the lesion. Further, details of the control will be described below.

It is also desirable to be able to rotate the radiation source at the point of treatment. This is necessary especially when the radiation source does not emit uniform radiation in all directions. An ideal source is, of course, a complete source if it is a point source that emits lobes in essentially one direction or a tube-shaped source that emits radially in all directions. Radiates the change.

Therefore, in order to equalize the radiation source emitted from the radiation source, it may be desirable to rotate the radiation source, thereby causing the lesion to receive a time-averaged dose. Absent.

Rotation is most easily achieved when the entire wire to which the radiation source is attached is unwound from the spool or cylinder described above to leave the wire free. The free end is then closed, for example, as shown in FIG.
Attached to. The fastening device itself is connected to a motor 24 via a connecting shaft or mandrel 28, as shown in the drawing.
And a device for generating a rotational motion such as If it is desired that the radiation source undergoes both translational (longitudinal) and rotational movement, the fastening device is actuated by a gear 26 coupled to an electric motor 27, as shown in FIG. The rack gear 25 can be telescopically attached to the rack gear 25. In one alternative, the guide rollers described above and used for longitudinal movement can be used in combination with a rotating device where the telescoping device is passive. Instead of using guide rollers for longitudinal movement, the telescoping member can be actuated by a motor suitable for moving back and forth and controlling movement at the lesion.

Obviously, rotation and translation can be achieved in many different ways, and a person skilled in the art will most certainly find many different solutions. As already mentioned, rotation is desirable for averaging over the lesion. However, for example, a stenosis may sometimes be placed on only one side of a blood vessel where healthy tissue is excessively exposed to radiation during rotation of the radiation source 4. To avoid this from happening, it may be convenient to provide radiation shielding around the outer periphery of the catheter 62, as shown in FIG. Although the latter method causes manufacturing problems not presented by the first method, the radiation source itself can be equally well shielded. The shielding member is
It is suitably provided as a layer or insert of some radiopaque material, such as platinum (Pt) or tungsten (W).

There are many possibilities to achieve the required correlation. Placed on one side of blood vessel V and FIG.
First, consider a lesion having a local anatomy as shown in FIG. In order for the same dose to be delivered to both the thinner ends of the stenosis S as well as to the thicker middle portion M, the speed of longitudinal movement is highest at the ends and radiation is It can be varied so that it decreases continuously when approaching. This is the only possible solution when a radioisotope is used as a radiation source.

In another method (in the case of an electrical radiation source), the speed can be kept constant and, instead,
The voltage supplied to the radiation source is varied relative to the anatomy of the stenosis.

The program by which this device is operated is based on the feedback principle, ie, the data regarding the size of the stenosis and the general local anatomy, as described above, which is always constant X-ray (or other means such as ultrasound). ) And supplied to a control unit, which operates on the basis of the appropriate sequence of movements and the principle by which the radiation energy of the radiation source is calculated.

FIG. 8 shows the stenosis below, where the radiation source is passed through the stenosis inside the blood vessel, and the dose is controlled by switching the radiation source on at A and off at B. Is shown showing how this is achieved. This implements control over the longitudinal extent, but the constriction is clearly receiving more radiation per unit volume in the thinner area in each of A and B than in the thicker midpoint C. Would.

Therefore, it is desirable to control the dose at each point. This can be achieved in at least two ways, as described below with reference to FIGS.

FIG. 9 shows a stenosis having a thinner portion T 'and a thicker portion T ". The movement through the stenosis according to the speed change shown below the image of the stenosis. By controlling the velocity, an essentially uniform dose, i.e., the amount of radiation per unit volume, is achieved.The velocity change uses input data from previously obtained X-ray or ultrasound or other surveys. Calculated by the control unit.

FIG. 10 shows another method. Similar stenosis can be treated by controlling the radiant energy at a constant rate of the radiation source. Thus, this graph shows the change in the energy of the emitted radiation with respect to the placement of the radiation source in the stenosis. As can be seen from this figure, the intensity is greater in the region T ″ where the constriction is thicker
Higher over

The energy is changed by changing the energizing energy processed by the control unit according to the calculated change. FIG. 16 is a flowchart illustrating a control program in the control unit. Therefore, first, the constriction must be characterized in terms of its size (and optionally its composition). Such data can be obtained from X-rays (which produce an image of the stenosis, mainly its length and thickness), sonography (cross-section and composition of various points along its length) or N
It can be obtained by MR (composition data).

Once the stenosis data (size and composition) is obtained, the radiation dose at each selected point in the stenosis can be calculated. For this calculation, commercially available software programs and AIC Software Inc. Even freeware, such as PHOTCOEF, which can be obtained from the company, can be used. This program calculates the _xo value for the stenosis that can vary significantly at various points within the stenosis depending on the composition.

Based on the calculated x _o values, the radiation dose required to achieve the required and preferred emitted dose is calculated. This allows the dose to be controlled by controlling the speed of movement v (x) of the radiation source along the lesion, as indicated earlier in the steps. That is, the speed v can be a function of the position x. Alternatively, the dose can be controlled by changing the energy E (x) as a function of the position e along the lesion.

Since there is a maximum value of the energy output that can be obtained, the change in radiation P is idealized by combining the two methods to achieve a sufficiently rapid treatment, ie P (v, x). May be needed.

Hereinafter, the present invention will be illustrated by the following limited examples. Example: We use an X-ray image of a stenotic coronary artery as an example, which is a so-called graphical representation of vasculature (see FIG. 1).

From this figure, it is possible to easily obtain the thickness of the stenosis as a function of the displacement X in the longitudinal direction. For example, IV
The composition of the material obtained from US (Intravascular Ultrasound) may be used as information to provide more accurate information for mass absorption data.

The mass absorption data is actually obtained by dividing a blood vessel and a stenosis into sections having a practical length dx as shown in the drawing. Therefore, the mass absorption coefficient is known as a function of the distance z from the radiation source for each section dx of the blood vessel (assuming it is located at the center of the blood vessel).

Next, the energy distribution from the radiation source is
It is considered known by calibration or by setting. One example of the energy distribution (radiation intensity as a function of energy) is shown in FIG. In this example, for simplicity of explanation, bremsstrahlung (Brehm
sstrahlung) is shown. The characteristic peaks of the radiation are easily handled as well.

The energy distribution is standardized (by integrating the intensity with respect to energy) and the spectrum is
Divided into sections dE (or adapted to functions or tabulated).

The order of this operation is arbitrary. The number of sections is also arbitrary and does not have to be equal to the energy section dE, but can be idealized to provide as close an accuracy result as necessary. The method of doing so can be selected from various known methods,
The method shown in FIG.
t).

In this way: the relative intensity for each part of the energy spectrum is known; the material composition as a function of z for each section of the blood vessel; and therefore the mass absorption as a function of z Coefficient data is easily obtained for each energy portion of the spectrum, calculated by commercially available programs, or obtained from a table (in the latter case, writing may be required).

[0051] Then, each segment relative relationship has been established properly for dx I = I (0) exp (z / z 0), wherein, · z ₀ is dependent on the energy of the composition and radiation materials I (0) is the intensity of the radiation at z = 0, and I is the intensity of the radiation as a function of the distance z.

The absorbed intensity is then the intensity that is not transmitted (the absorbed energy is a loss of intensity per unit time). As shown in FIG. 14, the location of the stenosis is divided into three sections with different material properties: blood B, stenosis S and muscle tissue M, each section having its own mass. It has an absorption coefficient.

In practice, however, each material (for reasons of computational accuracy) is also divided into a number of smaller sections in the z-direction, and the energy / intensity transferred in these sections is calculated. , Thereby obtaining how much energy has been absorbed in the section.
Each section dz has a mass absorption coefficient of its own material and energy properties.

Finally, this calculation is made for all energies according to the division of the energy spectrum shown in FIG. By way of example, stored energy for various portions of energy is shown in FIG. Energy is a function of distance in five different energy distributions d
For E (E1 to E5), it was accumulated in blood B, stenosis S and muscle tissue M. The mass absorption value for the stenosis was evaluated only in this example. The center of the radiation source is
0.5 from the blood vessel through which blood flows between the radiation source and the stenosis
mm. The model may be further refined, for example, by a portion of the vessel wall material inserted between the stenosis and the muscle tissue.

Finally, when the length of the blood vessel emitted from the point source is evaluated or measured (as long as this length is small compared to the length of the part of the blood vessel to be treated)
This is not important), and it is easy to calculate the velocity at each section dx of the blood vessel, ie at each point x.

Example: It is assumed that the dose to be supplied to the position of z = 2 mm is 20 Gy. When the light source is not moving, a 0.1 mm long portion of the blood vessel is illuminated. From the above calculations, the irradiation rate per vessel length of 0.1 mm is 2 Gy / sec.

The time for feeding 20 Gy to a blood vessel length of 0.1 mm is 10 seconds, that is, the moving speed is 0.1 / 1.
0 mm / sec. Uniform thickness and length 3m
A typical stenosis of m requires 300 seconds or 5 minutes to treat.

As mentioned above, the above calculations are made for each section of the stenosis, and the corresponding velocity changes can be as shown in FIG. Figure 9 is an example of a calculated velocity change (velocity as a function of x) after extracting information and turning it into motion to achieve a constant dose at depth. Other ideal energy storages may be the subject of future research and may be calculated and achieved by this method as well.

The above example did not use the possibility of adjusting the energy of the radiation source to be activated electrically.
It is contemplated that a similar calculation may be achieved by changing the energy. This allows the treatment to be more idealized with respect to treatment time, desired or undesired energy storage, and the like.

[Brief description of the drawings]

FIG. 1a is a cross-sectional view of a stenotic blood vessel.
FIG. 1b is a cross-sectional view of the blood vessel after performing PTCA.

FIG. 2 is a sectional view showing the apparatus of the present invention.

FIG. 3 is a sectional view showing details of the tip of a catheter to be used with the present invention.

FIG. 4 is a sectional view showing an example of a radiation source that can be used in the present invention.

FIG. 5a is a perspective view of one embodiment of a mechanism for controlling movement of a radiation source. FIG. 5b is a cross-sectional view of another embodiment of the mechanism for controlling the movement of the radiation source.

FIG. 6 is a cross-sectional view of a catheter having a radiation shielding member.

FIG. 7 is a cross-sectional view showing an example of local anatomy of a stenosis.

FIG. 8 shows the change in stenosis and dose after PTCA treating the stenosis using the on-off method at a constant dose.

FIG. 9 illustrates the change in dose achieved by controlling the speed of movement of the radiation source.

FIG. 10 is a graph showing the change in dose achieved by controlling radiation energy from a radiation source.

FIG. 11 is a graph showing the divided sections of an X-ray image for calculation purposes.

FIG. 12 is a graph showing changes in bremsstrahlung for a radiation source.

FIG. 13 is a graph showing split sections of energy change for computational purposes.

14 is a graph showing calculated absorbed doses for various energies in the energy spectrum of FIG.

FIG. 15 is a graph showing the change in dose achieved by changing the speed of movement of the radiation source.

FIG. 16 is a simple flowchart for reaching an ideal dose change.

[Explanation of symbols]

4 X-ray generator, 6 wire, 8 catheter, 10 spool, 12 control unit, 14 X-ray detector, 20 lead wire,
21 drive roller, 22 electric motor,
23 fastening device, 24 electric motor,
25 rack gears, 26 gears

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[Procedure amendment]

[Submission date] January 23, 2001 (2001.1.2)
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 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Jonas Tylen SA-754, Sweden 34 Uppsala, Vikingagatan 44

Claims (14)

[Claims] 1. A treatment site comprising an elongated member (6) suitable for insertion into a patient's body, and a source of ionizing radiation (4) provided at a distal end of said elongated member (6). Device for the controlled delivery of ionizing radiation, comprising a drive unit (21,22; 23,24,25,26) operable to cause movement of an elongated member (6).
And the drive units (21, 22; 23, 24, 25, 2)
A control unit (12) for controlling the operation of 6),
An apparatus comprising: 2. The device according to claim 1, wherein the elongate member is selected from a wire (6) and a needle. 3. The device according to claim 1, wherein the radiation source is a radioisotope. 4. Apparatus according to claim 1 or 2, wherein the radiation source is an electrically activated radiation source, preferably a miniaturized X-ray tube. 5. The device according to claim 1, wherein the control unit (12) comprises a drive unit (21, 22;
23, 24, 25, 26) can be programmed to cause the radiation source (4) to move at a controlled and variable speed, not only longitudinally but also longitudinally at the treatment site. ,apparatus. 6. The apparatus according to claim 1, wherein the control unit is programmable to cause the drive unit to rotate the radiation source. 7. The device according to any one of the preceding claims, further comprising a catheter (8; 62) having a lumen into which the elongate member can be inserted. 8. The device according to claim 1, wherein the drive unit carries a pair of elongated members to cause movement of the elongated members. An apparatus, including a guide roller (21). 9. The apparatus according to claim 1, wherein the drive unit is capable of inserting a base end of the elongated member and rotating the elongated member. And optionally a fastener (23) coupled to allow longitudinal movement of the elongate member. 10. The device according to claim 1, wherein a shielding member is provided to prevent radiation from the radiation source from penetrating into healthy tissue. 63),
apparatus. 11. Apparatus according to any one of the preceding claims, wherein the radiation source comprises a shielded housing into which the X-ray detector (14) can be retracted. A device provided for the purpose of calibration and function check. 12. A method for providing a controlled dose of ionizing radiation to a lesion at a treatment site, the method comprising providing an elongated member suitable for insertion into a patient. Attaching a source to the distal end of the elongate member, the elongate member being capable of causing a controlled movement of the elongate member at the lesion and controlling the drive unit to control the operation of the drive unit. Coupling to a drive unit that can be coupled to a programmable control unit; and to generate an operating sequence for the drive unit,
Providing the control unit with information about the characteristics of the lesion to be treated; inserting the elongate member into the body and placing a radiation source at the lesion to be treated by radiation; Operating the drive unit under the control of the control unit according to programmed information. 13. The method of claim 12, further comprising the step of obtaining characteristics of the lesion to be treated by one or more of X-ray imaging, ultrasound imaging, and NMR. Including methods. 14. The method of claim 12 or claim 13, wherein the lesion is a stenosis in a coronary artery.