MX2007000780A - Adaptive intracavitary brachytherapy applicator - Google Patents

Abstract

The invention is a novel adaptive CT-compatible brachytherapy applicator with remotely-controlled radial and longitudinal motion radioactive source lumen shields that can be manipulated by the radiation oncologist to optimize the dose distribution to the target and normal tissue structures for brachytherapy procedures.

Description

ADAPTABLE INTRAVAVITAR BRAQUITERAPY APPLICATOR Field of the Invention The invention of the present description provides an intracavitary brachytherapy applicator compatible with the acquisition of images, adaptable,. Novelty (ICBT) (for its acronym in English) with remotely controlled colpostatic protections that can be manipulated to minimize the artifacts of a computerized tomography image or to optimize dose distribution with respect to normal and targeted tissue structures for brachytherapy procedures against cancer. . Background of the Invention More than 12,000 new cases of cervical cancer are expected to be diagnosed in the United States of America in 2003. (American Cancer Society, Cancer Facts and Figures 2003). ICBT is an integral part of the treatment regimen for cervical cancer. It is also used in the treatment of other gynecological malignancies, such as vaginal and endometrial cancer. These cancers, combined, together account for approximately 56,000 new cases in the U.S.A. each year (American Cancer Society, Cancer Facts and Figures 2003) of which approximately 20% or 11,200 cases could be treated with ICBT procedures. In addition, throughout the world, every year more than 600,000 women develop some form of cancer Ref.179223 gynecological, according to the World Health Organization. Traditionally, many cancers of the cervix are treated with radiation therapy. Between 1996 and 2000, approximately 84% of these treatments in the U.S.A. were with 137Cs sources of a low dose rate (LDR), with the rest using 192Ir high dose rate (HDR) (for its acronym in English) (Eifel P, et al, Patterns of Radiotherapy Practice for Patients with Carcinoma of the Cervix (1996-1999): A Patterns-of-Care Study, Proceedings of the 45th Annual ASTRO Meeting, 2003). One way to develop such radiation is through an ICBT procedure. In an ICBT procedure, radioactive resources are manually or automatically loaded into applicators placed within the uterine canal during an operative procedure by means of a procedure called postload. The ICBT, alternatively or additionally, can be administered pre-operatively or post-operatively and can be grouped in pairs with external beam radiotherapy, chemotherapy, or both. The cells or target cancerous tissue are typically irradiated by the use of a brachytherapy applicator. The common applicators contain right and left ovoids or colpostatics and are made of stainless steel. Several varieties of these applicators also have fixed, special tungsten protections, designed to reduce complications due to inadvertent irradiation of the rectum, bladder or other surrounding tissues. The common practice to place the alignment of the protection with the bladder and the rectum depends on the anatomy of the patient and the experience of the doctor. Additionally, the size, shape, thickness and placement of these protections can have a substantial effect on the radiation dose received by normal tissues near the target site, particularly the rectum in the case of cervical cancer, and the rates of complications have been shown- that will depend directly on the dose received by these organs. The commonly used clinical treatment planning systems, however, are typically unable to accurately account for the effects of protections leading to errors of 30% or more and the predicted dose for critical organs (Mohán R, et al. , Int J Radiat Oncol Biol Phys 1985a; 11 (4): 861-8; Mohán R, et al., Int J Radiat Oncol Biol Phys 1985b; 11 (4): 823-30; Weeks KJ, Med Phys 1998; 25 ( 12): 2288-92; Williamson JF, Int J Radiat Oncol Biol Phys 1990; 19 (1): 167-78). Other studies have shown that dose disturbances resulting from applicators and protection from inter-sources are also clinically significant and should be modeled. Fragoso, et al, found that errors as large as 20% could result from not explicitly model steel ovoid applicators and source spacers in LDR treatments (Fragoso M, et al., Proceedings of the 2003 AAPM Annual Meeting, 2003). Gifford, et al. He concluded that the explicit modeling of the tandem applicator was also important. Intra-source and inter-source attenuation and the presence of a mouthpiece screw were found to have significant effects on the local dose field (Gifford K, et al., In Proceedings of the 2003 AAPM Annual Meeting, 2003). An integral component in determining the dose distribution to be received by the target and non-target areas is the placement of any radiation protections within the ovoid. The planning of the dose distribution of ICBT frequently involves the use of a three-dimensional visualization of the target areas and the surrounding anatomical structures to determine the appropriate position of the implanted applicator to maximize a dose distribution of the radiation over the target areas. Techniques such as computed tomography (CT), magnetic resonance imaging (MR), or positron emission tomography (PET)) they have been used in the past to generate a three-dimensional treatment plan for ICBT procedures. Such Techniques are limited by the fact that the protections used in the ICBT applicators can interfere with these various planning methods by distorting the images of the location of the implant and causing artifacts of stripes, making a determination of the optimal placement of the applicator inside the body cavity very difficult to determine. US Patent No. 5,562,594 discloses a CT-compatible applicator design (the "Weeks" applicator) that allows CT 3D dosimetry (Weeks KJ and Montana GS, Int J Radiat Oncol Biol Phys 1997; 37 (2): 55-63). The ovoid of Weeks has carriers of the sources with protected tungsténo that are loaded later after the acquisition of images of CT. The external shape of the ovoid and serial system of mini-pylons from Fletcher-Suit-Declos (FSD) seems to have been the basis for the shape of the Weeks applicator. However, the Fletcher-like, fixed protections have been removed and replaced with tungsten protections that are manually loaded in conjunction with the 137Cs sources. The Weeks applicator has been used to develop a technique for localization of the CT-based applicator (Lerma FA and Williamson JF, Med Phys 2002; 29 (3): 325-33) improved. This study showed that it was possible to support the planning of the 3D dosage involving the Detailed Monte Cario 3D dose calculations, modeling of source positions, providing protection and protecting inter-applicators accurately. However, the Weeks applicator has several disadvantages. For example, the Weeks applicator is not adaptable for a subsequent charge to remote control (the load of the radioactive source in the post-insertion of the applicator and the placement inside the body cavity) which increases the exposure of the LDR brachytherapy radiation, and can not be used in its entirety for applications, HDR or a pulsating dose rate (PDR). In addition, to adapt the protections after loading, the arms connected to the ovoids are much more bulky than those of a standard FSD applicator. The increased size of the arms makes it more difficult to insert the vaginal packing necessary to establish a distance with the bladder and rectum from the sources of the radiation. This added volume also has a potentially negative impact on the comfort of the patient suffering from the treatment. Another commercial option available is the "standard CT / MR applicator" based on a Royal Arsden design by Nucletron Corporation. It is designed with a special composite pipe to eliminate the distortion of CT or MR images. This applicator is available in Different lengths and diameters of the ovoids to optimize the distribution of the dose and reduce the dose of the mucosa. However, this applicator was not designed for use with any protection and therefore, its use leads to exposure of the rectum and bladder or other surrounding tissue to unnecessarily high doses of radiation which can lead to clinical complications. Therefore, there is a need for a brachytherapy applicator that is feasible as a radiation source after loading but that is still capable of being manipulated to allow the acquisition of improved images with a minimum generation of artifacts. Brief Description of the Invention The present disclosure provides a novel adaptive brachytherapy applicator that is compatible with image acquisition and that includes one or more linearly (translationally) and radially (rotationally) remotely controlled protections. This new applicator can be used for LDR, PDR, and / or HDR brachytherapy. The use of certain embodiments of the present invention is expected to improve upon the clinical outcome of common brachytherapy, in particular by reducing the rate of complications. In such modalities, the ability to alter the position of the protection during an image acquisition, such as a CT scan, may reduce the artifacts of the image. whereby the precision with which important anatomical structures can be delineated is increased. In alternative modalities, the ICBT applicator has one or more movable protections, which can provide an increased degree of freedom whereby a treatment planning system guided by iterative images is allowed to optimize or adapt the dose distribution based on the geometric relation of patient-applicator. In such modalities, the physician or the user can maximize the dose delivered to the target tissue (such as a cervical carcinoma) while concurrently reducing the exposure of the surrounding tissues (such as in the case of cervical cancer, the wall of the rectum and bladder). In embodiments containing one or more protections, the movement criteria of the protection (s) of the present invention (translation and rotation) will allow the treatment to be based on the relative patient / applicator relationship as derived from one modality of the image. The coupling of this technology with a rapid dosing motor (within minutes) capable of accurately calculating the dose disturbance around one (s) protection (s) can further optimize the use of this invention. Certain embodiments of the present invention provide a brachytherapy applicator that includes a lumen of the radioactive source, at least one protection associated with the lumen of the radiation source, and a mechanical mechanism connected to the protection (s) that is capable of controlling the movement of the protection (s) in at least one direction with respect to the lumen of the radioactive source. In other embodiments, the brachytherapy applicator of the present invention includes: a pivot joint; a tandem device that has a lumen of the radioactive source; wherein the tandem device is connected to the pivot joint through an arm of the tandem device; at least one ovoid having a lumen of the radioactive source, wherein at least one ovoid is connected to the pivot joint by means of an arm of the ovoid; and at least one protection associated with at least one ovoid, wherein at least one protection can be remotely moved. In some of these embodiments, the brachytherapy applicator further includes: a sliding guide for the protection containing at least one protection, wherein the protection includes a region of interaction of the gears and a counter-threaded element; a rotating shaft that has an associated meshing that interacts with the de-interaction region of the protection gear; and a linear shaft having a threaded portion that interacts with the counter-threaded element of the guard sliding guide.

In certain embodiments of the brachytherapy applicators of the present invention, the lumen of the radioactive source is subsequently loaded with a radioactive source. In the modalities that contain ovoids, the radioactive source can be charged later by means of the ovoid arm. In certain other embodiments, the brachytherapy applicators of the present invention further include a cap that fits over the lumen of the source. Some of these applicators also include registration markers that are connected to the source lumen or are present in or on a cover. In certain alternative embodiments, at least one protection may be internal with respect to an outer envelope that covers the lumen of the radioactive source and in some of these embodiments, the protection (s) is (are) composed of tungsten or a tungsten alloy. In alternative modes, the movement of the protections can be linear or rotary. In some of these modalities, a rotary movement is controlled by means of a rotary axis, while a linear movement is controlled by means of a linear or longitudinal axis. These axes may additionally be composed of nickel-titanium in certain embodiments. Certain embodiments of the present invention may also include a manual mechanism for the application of a rotary force to the rotary axis or to the longitudinal axis. However, alternative embodiments may include a control station that controls the rotational force applied to the rotary axis or the longitudinal axis. In addition, in some of these modalities, the movement of the brachytherapy applicator's protection (s) can be controlled remotely by means of a telemetry signal. In still other embodiments, the position of the protection (s) can be confirmed by means of a feedback mechanism to confirm, such as optoelectronic devices. The present invention also provides methods for the treatment of neoplastic disorders. Certain of these methods include providing a brachytherapy applicator, inserting the brachytherapy applicator into a body cavity, then altering the position of a brachytherapy applicator protection after insertion into the body cavity, followed by irradiation of the 'neoplastic tissue. Alternative modalities of these methods also include altering the position of a protection during the acquisition phase of the treatment images to alter the quality of the image artifacts caused by the presence of the applicator. Still other modalities include the alteration of the position of a protection after a radioactive source has been charged in the applicator of brachytherapy In some of these modalities, the position of a protection is altered to change the distribution of the radiation dose. BRIEF DESCRIPTION OF THE DRAWINGS This invention can be better understood by reference to the following description taken in conjunction with the appended figures,. in which like reference numbers identify similar elements, and in which: Figure 1 shows the basic structure of a brachytherapy applicator; Figure 2 shows the position of a brachytherapy applicator within the patient; Figure 3 is a schematic view of an ovoid of a brachytherapy applicator; Figure 4A is a schematic view of the internal mechanisms of an ovoid of a brachytherapy applicator with adaptive protection; Figure 4B is a schematic view of the internal mechanisms of an ovoid of a brachytherapy applicator with an adaptive protection of a proximal view; Figure 4C shows the association of a rotary shaft with a sleeve / shaft; Figure 4D shows the .association of an axis Rotary with a flat side; figur 4E shows the association of a rotary shaft with a spring; Figure 5 shows a schematic view of a protection slide guide; Figure 6? shows the position of a protection with respect to the internal mechanisms of an ovoid; Figure 6B is a schematic view showing the placement of the protections with respect to the internal mechanisms of an ovoid; and Figure 7 shows the position of the registration wires in a lid of the ovoid; Figure 8 shows a PC-based control unit for a brachytherapy applicator. Detailed Description of the Invention The present disclosure provides a novel adaptive brachytherapy applicator that is compatible with image acquisition and includes one or more remotely controlled radially (rotationally) and linearly (translated) protections within a ovoid (or colpostat), a tandem device, or other structure containing a lumen of the radioactive source. This novel applicator can be used for LDR, PDR, and / or HDR brachytherapy. The use of certain embodiments of the present invention is expected to improve upon clinical outcomes of common ICBT, in particular by reducing the rate of complications. The ability to alter the position of any protection during an image acquisition, such as a CT scan, can reduce the artifacts of imaging, thereby increasing the precision with which important anatomical structures can be delineated. . ' The improvement in the accuracy of the delineation of the objective may allow adaptation of the minimum target dose and the shape of the iso-dosing surface of the prescription. In addition, a movable protection (s) can provide an increased degree of freedom whereby a treatment planning system guided by iterative images is allowed to optimize or adapt the dose distribution of the radiation based on a geometric relation of patient-applicator, thus maximizing the dose delivered to the target diseased area, while concomitantly reducing the dose received by the tissue protected by the protection. For example, in the treatment of a cervical carcinoma, the dosage of the carcinoma could be maximized while the protection could reduce the dose of radiation on the wall of the rectum and the bladder. In certain embodiments, the movement criteria of the protections of the present invention may allow the treatment to be based on the relationship relative of patient / applicator as derived from a modality of an image. In other embodiments, the coupling of this technology with a 'fast dosing engine (within minutes) capable of accurately calculating the dose disturbance around one (s) protection (s), can optimize the use of this invention. . The methods of discrete ordinates or Monte Carlo, fast, can also be used in such capacity. The introduction of a remotely movable protection in a brachytherapy device as provided by the present invention is adaptable for most brachytherapy devices of any type. For example, gynecological, thoracic, head and neck, gastro-intestinal, and breast cancers can be treated with brachytherapy applicators of the present invention. Certain embodiments of the brachytherapy device of the present invention include. 'a lumen of the radioactive source, which is capable of containing a radioactive source, and the protection that is used to reduce or obscure the radiation emanating from the lumen of the source in certain directions. These embodiments also include a mechanism for directing the placement of the protection with respect to the lumen of the source after the applicator has been inserted into a cavity of the cupola. The protection of these applicators it can be internal with respect to the lumen of the source or it can be external with respect to the lumen of the source (for example, mounted along an axis of the ovoid in a brachytherapy applicator similar to FSD). The protection only needs to be placed between the radioactive source and the area of the tissue that is to be protected from radiation. Some of these modalities may contain more than one protection. In certain embodiments, the placement of the protection with respect to the radioactive source or the source lumen can be manipulated by means of a mechanical mechanism such as a tape or wire of high resistance to distortion torque. In such embodiments, the tape or wire may extend from the applicator to a position outside the patient's body. In certain embodiments, the wire or tape may be inside an outer pipe that forms an axis of the wire / tape coating type. The wire or tape may have a rotational force applied thereto to provide a rotary control over the location of the protection. For example, a gear mechanism may be coupled to the guard to provide rotary control. Alternatively, the wire or tape can be connected to a threaded element in such a way that the application of a rotating force to the wire will cause the linear movement of a counter-threaded element attached to the wire. protection. Therefore, protection in certain embodiments can be controlled in the position in a radial or linear manner (or both). · In certain embodiments, the brachytherapy device also includes a fixation mechanism to ensure the immobility of the protection in the desired location / orientation. Although in still other modalities, a closed circuit feedback reading (passive or active), using for example optoelectronic devices (including optical fibers, LEDs, photodiodes, or the like), is implemented to provide the user with the security of the location of the protection. Some modalities also include a "base" position for failure of the protection (s) that is (n). defined (s) based on the concept of the common FSD ovoid. Alternative embodiments of the present invention may use a remote control mechanism associated with the protection and which does not extend proximally outside the patient's body. In such embodiments, the position of the guard can be controlled by means of an external signal, which activates or deactivates a mechanical mechanism associated with the applicator to manipulate the position of the guard (s). Such signals may include, but are not limited to, radio waves, infrared waves, and sound waves or other telemetry methods.

Figure 1 shows the structure of an embodiment of an ICBT applicator similar to FDS of the present invention. This embodiment of the applicator includes a tandem device 2 connected to a pivot joint 4 by means of an arm of the tandem device 2a and a pair of colpostatus / ovoid 3 which are connected to the pivot joint 4 by means of a pair of arms 5 of the ovoids. In certain embodiments, the pivot joint 4 serves only to connect the arm of the tandem device 2a to the arm 5 of the ovoid, while in other certain embodiments, the pivot joint 4 functions not only as a connection point but also makes alterations possible. of the angle between the arm of the tandem device 2a and the arm 5 of the ovoid. The tandem device 2 and the ovoids 3 are designed to contain a radioactive source (s) during the irradiation of a patient. In certain embodiments, the arm of the tandem device 2a and / or the arms 5 of the ovoids can be adapted to allow the radioactive source (s) to be (are) charged through them. in the tandem device and the ovoids, respectively. This can be done after the applicator has been placed inside the body cavity in a process called after loading. Figure 2 shows the placement of an FSB-like ICBT applicator of the present invention during the treatment of a patient who has cervical cancer. The tandem device 2 is inserted into the uterus 7 while the ovoid 3 is placed in the vagina, next to the external mouth of the cervix. During an intracavitary brachytherapy treatment, an FDS-like modality of the present invention (as shown in Figure 1) can be used. The radioactive sources can be placed within the tandem device 2 and the ovoids 3 to provide a pear-shaped dose distribution that surrounds just one target volume, with its longitudinal axis along the axis in tandem device. In certain embodiments of the present invention, the radioactive source (s) may be charged later in the applicator. In some of these embodiments, the radioactive source is inserted into the ovoids 3 by means of the arms 5 of the ovoids and the radioactive source is loaded into the tandem device 2 through the arm of the tandem device 2a. Prior to loading the radioactive source during such procedures, the applicator is frequently placed in the body cavity and images, such as orthogonal X-ray films, CT scans, MR scans, and / or PET scans are acquired to confirm their location, these images can also be used to determine and verify that the applicator has been placed optimally with respect to the anatomical location and the dosage of the radiation that will be delivered to the target area. Figure 3 provides a schematic view of an ovoid 3 containing a rectal shield 9, a shield 10 for the bladder and a lumen 11 of the radioactive source. These protections can be composed of any material that will partially or totally attenuate the radiation from the source that travels inward. A typical example of such material is tungsten, tungsten alloys, titanium, platinum, or any element of adequate high atomic number. In addition, the protection (s) may be of varying size, shape and thickness. A person skilled in the art will choose the size, shape and thickness based on the tissue being treated, the patient, the source of radiation and other relevant factors. In some embodiments of the present invention, the protection (s) may be interchangeable so that an oncologist who provides care may choose a protection of a specific size, shape and thickness that will provide the protection. optimal protection in relation to the anatomy of the patient, the target volume delineated, the critical structures delineated, the radioactive source used, or other factors.

During the treatment planning phase, the appropriate placement for maximum protection of a non-target tissue, such as the bladder and rectum in the case of cervical cancer, is calculated. In the prior art applicators, the protections could then typically be fixed in a permanent position prior to insertion of the device into the body cavity or attached to a supply vehicle of the same type and delivered to the applicator in the company of the source radioactive (as in the Weeks applicator). The present invention, however, describes applicators that include mechanisms for adjusting the position of the shield after the applicator, including the shield, has been inserted into the body cavity. Figure 4? shows a schematic view of an embodiment of an ovoid of the present invention that includes an adjustable protection in its position. This protection can be placed to protect non-target tissues such as the rectum or bladder, preferably the rectum in the case of cervical cancer. This embodiment of the present invention includes a cap 3a of the ovoid surrounding the lumen 11 of the radioactive source. The cover 3a of the ovoid provides a housing for a sliding guide 12 of the protection which is associated with a protection 9. The sliding guide 12 of the protection and the protection 9 they can be moved longitudinally or linearly with respect to the central axes of the ovoid itself 3, while the guard 9 can also be moved radially with respect to the central axis of the ovoid. The sliding guide 12 of the protection can be coupled by a threaded shaft 13, a rotary shaft 14 or both. The threaded shaft 13 can include a threaded section 13a at or near its end and is capable of moving the sliding guide 12 of the linearly upward and downward protection (distal to proximal) of the ovoid 3. The rotating shaft 14 is capable of rotating the shield 9 radially with respect to the longitudinal center of the ovoid 3. In certain embodiments, the rotating shaft or the threaded shaft is composed of a ribbon or wire of an alloy with shape memory such as nickel-titanium or the like, although another material that has a high torsional strength can also be used. The rotating shaft or the threaded shaft can alternatively be made of braided metal filaments or solid or braided filaments of high-strength synthetic fibers. In certain embodiments, the position of a guard 9 can be adjusted manually by means of a mechanical interaction of the threaded and / or rotary axes 13/14 (as shown in FIG. 4A) with the sliding guide 12 of the guard or 9/10 protection respectively. As shown in Figure 4B, a gear 16 associated with the rotary shaft 14 at or near its distal end can couple the shield 9/10 in such a way that a rotational force (torque) applied to the rotary shaft 14 could cause gear 16 to move to guard 9/10 radially. In a similar manner, the rotational force (torque) applied to the threaded shaft 13 can engage a counter-threaded housing 18 (as shown in FIG. 5) associated with the slide guide 12 of the guard causing the guide Sliding 12 of the protection moves longitudinally with respect to the ovoid axis lia. In certain embodiments, the protection glide guide may contain mechanical stops to restrict the degrees of rotation through which the glide guide 12 of the guard and the guard 9/10 can travel. When the shield 9 is moved linearly (proximally or distally) the "rotating shaft" 14a · can slide inside its tube 14b (similar to the way a wire can be pulled from its insulation) in such a way that contact between gear 16 and guard 9 (as shown in figure 4C) is maintained. In the alternative embodiments (as shown in 4D), a rotating shaft having a flat side 14c extending through the gear 16 toward the distal end of the cap 3a of the ovoid can be used. In these embodiments, the gear 16 can slide linearly along the rotary axis 14 in the company of the protection 9/10 and the sliding guide 12 of the protection to maintain its interaction with the 9/10 protection. In yet other embodiments, a spring-driven portion of the rotating shaft 14d can be used to maintain the interaction of the gear 16 with the shield 9/10 when the slide of the shield is moved linearly along the ovoid 3 (as shown in FIG. shown in Figure 4E). The sliding guide 12 of the guard, the gear 16, or the threaded section of the threaded shaft 13 (the "moving parts") can be made of any suitable material. In certain modalities, the material used to manufacture these moving parts will be based on mechanical strength (tensile and shear), the equivalence of tissue radiation characteristics, fatigue and thermal properties to allow multiple cycles of sterilization. In some embodiments, these moving parts are made of polysulfone or polycarbonate or other tissue-equivalent material that will contribute to a minimal disturbance for dose distribution when compared to translational aplxcators.

Figure 6? it provides an internal view of the ovoid 3 with a protection 9/10 with the sliding guide of the protection 12, as shown in Figure 4B, removed for reasons of clarity. In certain embodiments, the rotary shaft 14 and the threaded shaft 13 may extend and be supported by the ovoid holders 17 which also engage the lumen lining of the source. In the alternative embodiments of the present invention, such as those shown in Figure 6B, the ovoid can accommodate a threaded shaft 13 and a rotary shaft 14 for more than a 9/10 shield. In such modalities there may be a rectal protection 9, a protection for the bladder 10 or both, each having its own sliding guide 12 of the independent protection. In certain such embodiments, the sliding guide 12 of the guard associated with the rectal guard 9 may be in a position that is closer to the distal end of the ovoid 3 when compared to the bladder guard 10. Such modalities could be capable of independently positioning, both radially and linearly, rectal protection 9 and bladder protection 10. Alternative modalities may include more than one protection where one or more of the protections may be fixed with respect to their position relative to the radioactive source and not be coupled by the machinery of placement of the position within the ovoid 3. For example, in one embodiment, a protection for the bladder can be attached to the axis Ia of the ovoid, while the rectal protection 9 is movably positioned by the rotary shaft 14 through the engagement rotary 16 and the threaded shaft 13 through the counter-threaded housing 18 by means of its association with a sliding guide 12 of the protection. Still other embodiments may allow opposite configurations in which a bladder guard 10 is associated with a slip guide 12 of the shield, while a rectal shield could be fixed. In certain embodiments, the ovoid 3 may have a lid 3a of the removable ovoid that can be detached from the ovoid to expose the protection and the other moving parts to allow a visual inspection to ensure quality or to perform corrective maintenance. In yet other embodiments, the cap 3a of the ovoid of the present invention can be self-adapting to increase the overall size of the ovoid 3 to correspond to the anatomy of a given patient. In certain other embodiments, the adaptive applicator of the present invention will have a full profile of the ovoid handle (proximal tubing) similar to the Fletcher-Williamson HDR applicator assembly of Nucletron, common (~ 5 mm outer tubing diameter) to provide seamless integration in the clinic. While in still other embodiments, the profile of the adaptive applicator may be slightly larger to accommodate the channels for the threaded and rotating shafts 13/14 (external pipe diameter of ~ 7 mm). In certain embodiments, the angle of a linear axis of the ovoid with respect to the arm of the ovoid 5 is adjustable. In some of these modalities, the angle is adjustable between 15 ° and 45 °. In still other embodiments, a wire / ribbon can interact with a gear driven mechanism that allows remote controlled alterations of the shape or size of the shield. In addition, certain embodiments of the present invention may include registration markers. These record markers provide markers during image acquisition that make it possible for location locations of the protections to be determined or verified with respect to the patient's anatomy. These record markers may be composed of any radiopaque substance and, in some embodiments, may be in the form of a wire. The record markers may be included in or on various portions of the applicators of the present invention, including the lumen of the source, the tandem device or the ovoid. Figure 7 shows an embodiment of an ovoid 3 having registration wires 32 parallel and diagonal to, the ovoid. In such an embodiment, the registration wires 32 can be placed at an angle with respect to the plane in which the image portions 33 will be taken. Other embodiments of the present invention may have a variety of other configurations of the registration markers. In certain modalities, the registration markers may be associated with the location of the failure of the protection (s). In these modalities, the acquired images will have registration marks that identify, directly or indirectly, the location of the failure of the protection (s), making possible, by this, a more precise determination of the movements of the protection necessary to achieve the optional placement of the protections. In certain embodiments, the registration markers may be interspersed in the liner for the lumen of the source or the lia axis of the ovoid. In still other embodiments, the registration markers may be on or in the caps that are placed on the ovoid itself 3. In certain embodiments, the dosimetric simulation of discrete ordinates or Monte Cario of the adaptive applicator of the present invention may be used. to determine the final selection of the linear / angular movement range for the protection of the rectum, the protection for the bladder, or both. In addition, the ability of the present invention to internally adjust the location of a "protection both longitudinal as well as radially, it allows the movement of the protection during the acquisition of the CT image, or any other type of acquisition of the image, by which it is possible to reduce the artifacts produced by the protection in a brachytherapy applicator and provides improved and more accurate images for use in treatment planning. For example, the applicator can be inserted into a body cavity and the images can then be acquired with the protection (s) moved to a position closer to the axis of the ovoid, a CT scanner. of a single portion then acquires a first set of images before reaching the location of the moved protection. The acquisition of the scanner can then be interrupted briefly to move the protection to a more remote location before reassuming the acquisition of the rest of the CT portions. An initial scan image of the CT simulator can be made to select the interruption position between the two sets of images. In addition to allowing the capture of the improved images, certain embodiments of the present invention allow the planning of the inverse treatment of the treatment regime. For example, the radioactive source can be charged in the applicator with the protection in a predetermined position and then subsequently have the positions of the protection or the position of the protection. protection adjusted during radiation exposure to manipulate dose distribution more precisely. In certain embodiments, the applicator of the present invention also includes a manual mechanism for applying a rotary force on the threaded shaft 13 or the rotary shaft 14. These hand mechanisms may include simple mechanical fixings to the shaft, such as a rotating screw that connects to the axis. In still other embodiments, rotation of the rotary or threaded shaft can be controlled using quadrant indicators for reasons of simplicity. In such modalities, each mechanical quadrant may have a scale to show the location and orientation of the protection that is adjusted. The quadrants can also be designed for convenient surgical access. Alternative embodiments of the present invention may use a computer 27 as a control station. In certain such embodiments, the hardware components may include a laptop with LabVIEW 28 software and the PCI 29 motion controller card from National Instruments, Austin, Texas (www.ni.com), a 30 pulse unit for the control of the movement that has multiple axes. The position of the protection or protections can be controlled by means of a control station 27 as shown in figure 8. This control station can control the rotational position of a given guard by means of a rotary control 24 and the linear position by means of a linear control 25. In certain embodiments, the Rectal protection and protection for the bladder may have independent control stations (23 and 23a). Control stations, in certain embodiments, can control the activity of a motor 22 which could provide rotational force on the rotating shaft or the threaded shaft. In certain embodiments, the control station or the applicator itself may have an automatic (fail) base position imitating the FSD applicator (for LDR) or the Fletcher-Williamson applicator protection locations (for HDR / PDR) . The control station in certain modes can be used to place the protection in an appropriate location prior to the loading of the radioactive source in the applicator or the radioactive source can be charged in the applicator with the protection in a predetermined position and then subsequently have the positions of the protection or the protection position adjusted during the radiation exposure to manipulate the dose distribution in a more precise manner to conform to the surface of the pear-shaped isodium, prescribed, for the volume objective delineated. Algorithms for radiobiologically corrected volume-histogram planning can also be used to further optimize the location of protection throughout the course of treatment. It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention.

Claims (36)

1. CLAIMS Having described the invention as above, the content of the following claims is claimed as property. 1. A brachytherapy applicator, characterized in that it comprises: a lumen of the radioactive source; at least one protection associated with the lumen of the radiation source; and a mechanical mechanism connected to at least one shield that is capable of controlling · the radial movement of at least one shield with respect to the lumen of the radioactive source.
2. 2. The brachytherapy applicator according to claim 1, characterized in that a radioactive source is subsequently loaded into the lumen of the radioactive source.
3. 3. The brachytherapy applicator according to claim 1, characterized in that at least one protection is within the lumen of the source. .
4. The brachytherapy applicator according to claim 1, characterized in that the mechanical mechanism is controlled remotely by means of a telemetry signal.
5. 5. The brachytherapy applicator in accordance with claim 1, characterized by further comprising a feedback mechanism for confirming the position of at least one protection.
6. 6. The brachytherapy applicator according to claim 5, characterized in that the feedback mechanism comprises optoelectronic devices.
7. 7. The brachytherapy applicator according to claim 1, characterized in that it also comprises at least one registration marker connected to the lumen of the source.
8. 8. The brachytherapy applicator according to claim 1, characterized in that it further comprises a cover that fits over the lumen of the source.
9. The brachytherapy applicator according to claim 8, characterized in that it also comprises at least one registration marker on the lid.
10. 10. The brachytherapy applicator according to claim 8, characterized in that it also comprises at least one registration marker on the lid.
11. 11. A brachytherapy applicator, characterized in that it comprises: a pivot joint; a tandem device having a lumen of the radioactive source, wherein the tandem device is connected to the pivot joint by means of an arm of the tandem device; at least one ovoid having a lumen of the radioactive source, wherein at least one ovoid is connected to the pivot joint by means of an arm of the ovoid; and at least one protection associated with at least one ovoid, wherein at least one protection can be remotely moved.
12. 12. The brachytherapy applicator according to claim 11, characterized in that the lumen of the radioactive source of at least one ovoid is subsequently loaded with a radioactive source.
13. 13. The brachytherapy applicator according to claim 12, characterized in that the radioactive source is subsequently loaded into the lumen of the radioactive source by means of the arm of the ovoid.
14. 14. The brachytherapy applicator according to claim 11, characterized in that at least one ovoid further comprises an external liner and at least one protection is internal with respect to the outer lining of at least one ovoid.
15. 15. The brachytherapy applicator according to claim 11, characterized in that it further comprises: a guide for. slippage of the protection containing at least one protection, where the protection includes a region of interaction of the gears | and a anti-threaded element; a rotating shaft that has an associated gear which interacts with the gear interaction region of the guard; and a linear shaft having a threaded portion that interacts with the counter-threaded element of the guard sliding guide.
16. 16. The brachytherapy applicator according to claim 15, characterized in that the lumen of the radioactive source of at least one ovoid is capable of being subsequently charged with a radioactive source.
17. 17. The brachytherapy applicator according to claim. fifteen, characterized in that - the radioactive source is subsequently charged into the lumen of the radioactive source by means of the arm of the ovoid.
18. 18. The brachytherapy applicator according to claim 15, characterized in that at least one ovoid further comprises an outer liner and at least one protection is internal with respect to the outer lining of at least one ovoid.
19. 19. The brachytherapy applicator according to claim 15, characterized in that at least one protection is composed of tungsten or a tungsten alloy.
20. 20. The brachytherapy applicator in accordance with Claim 15, characterized in that the rotating shaft or the longitudinal axis is composed of nickel-titanium.
21. 21. The brachytherapy applicator according to claim 15, characterized in that it further comprises a manual mechanism for applying a rotational force to the rotating shaft or the longitudinal axis.
22. 22. The brachytherapy applicator according to claim 15, characterized in that it also comprises 'a control station that controls the rotational force applied to the rotary axis or the longitudinal axis.
23. 23. A method of treating neoplastic disorders, characterized in that it comprises: providing the brachytherapy applicator according to claim 1; inserting the brachytherapy applicator according to claim 1 into a body cavity; altering the position of at least one protection of the brachytherapy applicator according to claim 1 after insertion into the body cavity; e · irradiate the neoplastic tissue.
24. 24. The method according to claim 23, characterized in that it further comprises altering the position of at least one protection during a phase of acquisition of the image of the treatment to alter the quality of the artifacts of the image caused by the presence of the applicator.
25. 25. The method according to claim 23, characterized in that it further comprises altering the position of at least one protection after a radioactive source has been charged to the brachytherapy applicator according to claim 1.
26. 26. The method of compliance with claim 23, characterized in that it also comprises the change of position of at least one protection with the purpose of altering the distribution of the radioactive dose.
27. 27. The method of compliance with the claim 26, characterized in that the distribution of the radioactive dose is altered to reduce the radioactive dose applied to normal tissue.
28. 28. The method of compliance with the claim 27, characterized in that the normal tissue is the cervical tissue, the rectal tissue or the bladder tissue.
29. 29. A method of treating neoplastic disorders, characterized in that it comprises: providing the brachytherapy applicator according to claim 11, inserting the brachytherapy applicator according to claim 11 into a cavity of the body; altering the position of at least one protection of the brachytherapy applicator according to claim 11 after insertion into the body cavity; and irradiate the neoplastic tissue.
30. 30. The method according to claim 29, further comprising altering the position of at least one protection during the image acquisition phase of the treatment to alter the quality of the image artifacts caused by the presence of the brachytherapy applicator. .
31. 31. The method according to claim 29, characterized in that it further comprises altering the position of at least one protection after a radioactive source has been charged in the brachytherapy applicator according to claim 11.
32. 32. The method of compliance with claim 29, characterized in that it also comprises changing the position of at least one protection for the purpose of altering the distribution of the radioactive dose.
33. 33. The method according to claim 32, characterized in that the distribution of the radioactive dose is altered to reduce the radioactive dose applied to normal tissue.
34. 34. The method according to claim 33, characterized in that the normal tissue is the cervical tissue, the rectal tissue or the bladder tissue.
35. 35. The brachytherapy applicator according to claim 1, characterized in that the mechanical mechanism is also capable of controlling the linear movement of at least one protection.
36. 36. The brachytherapy applicator according to claim 35, characterized in that the mechanical mechanism is able to simultaneously control the radial and linear movement of at least one protection.