Abstract:
The present invention relates to the field of medical imaging and therapy of lesions that are detrimental to the body. The system is capable of both imaging and treatment with the same kilovoltage radiation source. Dual-use collimators produce a wide beam, which is not a pencil beam or a fan beam, to image and treat a target that has an enhanced radiation cross-section after taking up contrast agent containing a high-Z element. This results in increased radiation dose in the lesion. Furthermore, the significant drop in intensity of a low-energy radiation beam traveling through tissue is surmounted by continually aiming the beam at the target while moving it around the patient. Wide detectors opposing the radiation source permit the imaging and measurement of contrast in the target. More specifically this invention relates to a system, which optimizes delivery of kilovoltage x-rays to a lesion containing contrast agents in higher concentration than the surrounding normal tissues. Thereby subsequent delivery of radiation becomes cytotoxic upon interaction with the contrast.

Description:
RELATED U.S. APPLICATION DATA 
     This application claims priority of provisional application No. 60/825,289 filed Sep. 12, 2006 and entitled, Dual-Use Radiation System. 
     REFERENCES CITED 
     U.S. Patent Documents 
     
       
         
               
               
               
               
             
           
               
                   
                   
               
             
             
               
                   
                 5,008,907 
                 April 1991 
                 Norman et al. 
               
               
                   
                 6,125,295 
                 September 2000 
                 Cash and Weil 
               
               
                   
                 6,207,133 
                 March 2001 
                 Reszka et al. 
               
               
                   
                 6,366,801 
                 April 2002 
                 Cash and Weil 
               
               
                   
                 6,618,467 
                 September 2003 
                 Ruchala et al. 
               
               
                   
                 6,645,464 
                 November 2003 
                 Hainfeld 
               
               
                   
                 6,955,639 
                 October 2005 
                 Hainfeld and Slatkin 
               
               
                   
                 SN 11/671,222 
                 February 2007 
                 Weil et al. 
               
               
                   
                 SN 11/758,001 
                 June 2007 
                 Weil 
               
               
                   
                   
               
             
          
         
       
     
    
    
     Other Publications 
     Iwamoto et al., “The CT scanner as a therapy machine,” Radiother. Oncol. 19:337, 1990, Elsevier. 
     Solberg et al., “Calculation of radiation dose enhancement factors for dose enhancement therapy of brain tumours,” Phys. Med. Biol. 37:439, 1992, Inst. Phys. Pub. 
     Iwamoto et al., “Diagnosis and treatment of spontaneous canine brain tumors with a CT scanner,” Radiother. Oncol. 26:76, 1993, Elsevier. 
     Norman et al., “X-Ray phototherapy for canine brain masses,” Radiat. Oncol. Investig. 5:8, 1997, John Wiley and Sons. 
     Mesa et al., “Dose distributions using kilovoltage x-rays and dose enhancement from iodine contrast agents,” Phys. Med. Biol. 44:1955, 1999, Inst. Phys. Pub. 
     Rose et al., “First radiotherapy of human metastatic brain tumors delivered by a computerized tomography scanner (CTRx),” Int. J. Radiat. Oncol. Biol. Phys. 45:1127, 1999, Elsevier. 
     Weil et al., “Phase I Study of Contrast-Enhanced Radiotherapy with GMCSF for Advanced Cancers,” Submitted, 2007. 
     FIELD OF THE INVENTION 
     The claimed invention relates generally to medical imaging and therapy of lesions that are detrimental to the body using low-energy radiation with a radiation dose-enhancing agent. The system is capable of both imaging and treatment with the same kilovoltage radiation source and radiation agents. 
     BACKGROUND OF THE INVENTION 
     Contrast agents are widely used to improve x-ray or magnetic imaging of soft tissues. Compared to tissue, the heavy elements in diagnostic contrast media have greater capacity to absorb low-energy x-rays. This advantage is described as a higher x-ray “cross section”, and is measured by the substance&#39;s attenuation coefficient. The preferential blocking of x-rays by a heavy element allows an area to stand out against the background for better imaging, yet also results in more radiation dose delivered to the region nearby. This enhancement of absorbed dose from the contrast media used in radiographic imaging has been viewed as potentially dangerous. Concerns about increased cell damage caused by high radiation doses coming off contrast agents led to the idea that the potentially harmful effects could be exploited to improve radiotherapy 
     Contrast-enhanced radiotherapy (CERT) utilizes previously neglected effects of x-rays absorbed by radiographic contrast agents (U.S. Pat Nos. 6,125,295 and 6,366,801 and U.S. application Ser. No. 11/671,222). Resulting secondary ionizing radiation transfers significant energy and damages a limited volume. After concentrating contrast in a lesion, a lethal radiation dose can be delivered quickly to a lesion with minimal toxicity to nearby tissue. Our previous clinical development of CERT demonstrated the technique could safely create tumor debris in situ. A phase I trial of the technique in advanced cancer patients demonstrated the ability to precisely deliver high doses of x-rays to tumors with no toxicity and good palliation (Weil et al., “Phase I Study of Contrast-Enhanced Radiotherapy with GMCSF for Advanced Cancers,” Submitted, 2007). 
     The most important interactions between 120-150 kVp x-rays and a contrast agent are the attenuation (measured as, μ en , mass attenuation coefficient) and energy transfer (measured as, μ en/p , mass energy-absorption coefficient) as a result of collisions with the electrons in a high Z element, such as iodine. Iodine is commonly used for imaging since it is the high Z element in commercially available CT contrast media 
     The image reconstruction algorithm of a CT scanner employs numbers, Hounsfield units (HU), which are calculated as the beam spectrum is attenuated by the tissue in the patient,
 
 HU= 1000(μ tissue −μ water )/μ water   (Eqn. 1);
 
     where, μ tissue  and μ water , are the linear attenuation coefficients for tissue and water, respectively. Thus, the CT numbers (HU) have a linear relationship with the x-ray attenuation coefficients, and a Hounsfield Unit represents a change of 0.1% in the attenuation coefficient of water. 
     Marketed CT software readily acquires HU of injected pixels directly from the image. From the measured HU, the known mass attenuation coefficients from the National Institute of Standards and Technology for a given beam energy can be used to derive the concentration of iodine. In the above equation, μ tissue  is replaced by,
 
μ iodine ×[iodine concentration].
 
     On the other hand, the accompanying increase in energy transfer can enhance the dose delivered to a lesion by more than an order of magnitude. The dose enhancement factor (DEF) can be calculated for iodine versus water at a given energy as: 
     
       
         
           
             
               
                 
                   
                     DEF 
                     = 
                     
                       
                         
                           
                             
                               ( 
                               
                                 μ 
                                 
                                   cn 
                                   / 
                                   ρ 
                                 
                               
                               ) 
                             
                             1 
                           
                           * 
                           
                             f 
                             1 
                           
                         
                         + 
                         
                           [ 
                           
                             
                               
                                 ( 
                                 
                                   μ 
                                   
                                     cn 
                                     / 
                                     ρ 
                                   
                                 
                                 ) 
                               
                               
                                 H 
                                 ⁢ 
                                 
                                     
                                 
                                 ⁢ 
                                 2 
                                 ⁢ 
                                 O 
                               
                             
                             * 
                             
                               ( 
                               
                                 1 
                                 - 
                                 
                                   f 
                                   1 
                                 
                               
                               ) 
                             
                           
                           ] 
                         
                       
                       
                         
                           ( 
                           
                             μ 
                             
                               cn 
                               / 
                               ρ 
                             
                           
                           ) 
                         
                         
                           H 
                           ⁢ 
                           
                               
                           
                           ⁢ 
                           2 
                           ⁢ 
                           O 
                         
                       
                     
                   
                   ; 
                 
               
               
                 
                   ( 
                   
                     Eqn 
                     . 
                     
                         
                     
                     ⁢ 
                     2 
                   
                   ) 
                 
               
             
           
         
       
     
     where μ en/p  is the mass energy-absorption coefficient of iodine or water (at the spectral energy), and f 1  is the fraction by weight of iodine in the lesion. 
     The DEF can be as high as 37:1 with commercially available iodinated-CT contrast media, which was sufficient to destroy most tumors in our study. Moreover, the delineation between the high dose in the contrast-painted tumor to the low dose in the tissue takes place in under 50 μm(&lt;10 −4  m). Comparable fall-off for all other therapeutic radiation techniques, e.g., megavoltage beams, seeds, particles, is on the order of centimeters (10 −2  m). 
     An infused lesion is imaged and the concentration of high Z material in the target is determined. If the imaging is done with a CT scanner the CT numbers (Hounsfield Units) can be used to calculate the dose enhancement factor for CERT. Likewise, if a different type of digital detector is employed the dose enhancement factor can be derived from the attenuation coefficients measured with multiple beams. If, after calculating the dose enhancement factor for CERT, the potential enhancement is too low, the contrast infusion is repeated until there is sufficient high Z material in the target to produce adequate dose enhancement. Following delivery of radiation agents and confirmation of a minimal contrast concentration; the lesion is treated with radiation. The radiation is best delivered with external radiation beams from multiple directions. It is extremely difficult to deliver radiotherapy beams from multiple directions with existing kilovoltage technology. 
     Another critical component of this invention is quantification and dosimetry of the delivered dose of radiation. The penetration of the radiation through tissue will decrease the flux and also change the spectrum by hardening the beam, i.e., the average beam energy increases as lower energy photons are attenuated and higher energy photons relatively predominate. These parameters are influenced by the residence time of the radiation agent in the tumor and are dependent upon the kinetics of diffusion out of the target site. In clinical practice these variables are accounted for and the DEF is calculated with planning software. 
     This invention does not employ radiopharmaceuticals. The high doses to the organs when using radioactive targeting moieties limit the use of the technology. The utility of the radiation treatment agents with dual-use collimation of kilovoltage radiation described herein, especially absent attached radioactive isotopes, for enhancing the effect of radiation therapy has not been taught elsewhere. 
     The types of tumors that can be treated by this invention include primary and metastatic bone and soft tissue tumors. When the location of these tumors is known, one modality of treatment is to administer the radiation agent, then concentrate the radiation to the area of the tumor, thus increasing the ratio of absorbed radiation dose in the target versus normal tissue. In other cases, where many tumors are in need of treatment, or where there is disseminated disease, it is possible to administer the radiation agent then give relatively low radiation to the whole body. This way of treating the patient may treat micro-metastatic sites, or small tumors, before they grow into bigger and less treatable tumors. 
     Contrast agents and tumor targeting techniques at present do not achieve adequate tumor concentration of heavy atoms for CERT except with direct intratumoral injection of contrast (U.S. Pat. Nos. 6,125,295 and 6,366,801 and Weil et al., “Phase I Study of Contrast-Enhanced Radiotherapy with GMCSF for Advanced Cancers,” Submitted, 2007). In the example from Hainfeld et al (U.S. Pat. Nos. 6,645,464 and 6,955,639) employing intravenous delivery of gold nanoparticles into experimental mouse tumors; they measured gold uptake in the tumor at 0.23% weight/volume. However, for practical implementation of CERT, it is necessary to obtain ˜2.5-30% weight/volume of a heavy element in a tumor. Therefore, as reported in this study with gold nanoparticles, the dose enhancement would be 10-100 times less than required for clinical efficacy. 
     The prospects of safely using kilovoltage beams even for tumors at depth are improved with a significant DEF. Rather than overdosing the skin in an effort to increase the radiation dose to a deep lesion, the DEF may enable treatment with lethal dosing of the tumor and relatively low dose to the skin. However, as a result of significant tissue absorption of kilovoltage x-rays, tumors deeper than 5 cm require multiple beams in order to safely deliver an adequate radiation dose. 
     Others have employed devices to use a single machine for imaging and therapy. Norman et al have described treatments employing a kilovoltage computerized tomography scanner with collimation altered to produce a pencil beam, a small round or rectangular beam (U.S. Pat. No. 5,008,907; Iwamoto et al., “The CT scanner as a therapy machine,” Radiother. Oncol. 19:337, 1990, Elsevier; Solberg et al., “Calculation of radiation dose enhancement factors for dose enhancement therapy of brain tumours,” Phys. Med. Biol. 37:439, 1992, Inst, Phys. Pub.; Iwamoto et al., “Diagnosis and treatment of spontaneous canine brain tumors with a CT scanner,” Radiother. Oncol. 26:76, 1993, Elsevier; Norman et al., “X-Ray phototherapy for canine brain masses,” Radiat. Oncol. Investig. 5:8, 1997, John Wiley and Sons.; Mesa et al., “Dose distributions using kilovoltage x-rays and dose enhancement from iodine contrast agents,” Phys. Med. Biol. 44:1955, 1999, Inst. Phys. Pub.; Rose et al., “First radiotherapy of human metastatic brain tumors delivered by a computerized tomography scanner (CTRx),” Int. J. Radiat. Oncol. Biol. Phys. 45:1127, 1999, Elsevier). These treatments were done with fractionated radiotherapy. The use of megavoltage computerized tomography capable of imaging and treatment has also been developed (U.S. Pat. No. 6,618,467). 
     The therapeutic profile of contrast-enhanced radiotherapy can be of benefit since tumor control rates are better with increased radiation doses. To satisfactorily enhance the kilovoltage radiation dose absorbed by a solid tumor in the presence of a high Z element, it is necessary to be able to safely deliver adequate radiation to all locations in the body. Improved efficacy and/or control of such delivery are desired. 
     SUMMARY OF THE INVENTION 
     To address at least the foregoing, some embodiments of the present invention provide a system, apparatus, method and means to generate an image and radiation treatment with a single radiation source modified with dual-purpose collimation, a capability to move in an arc or circle about a patient while aiming at the internal target, and enhance the radiation dose safely in the target loaded with a radiation enhancing agent. In a further aspect, the painted internal target is first imaged and then a radiation treatment plan is determined. 
     According to some embodiments, a dual-use collimator produces a wide-based pyramidal beam, which continually is aimed at a contrast-enhanced lesion, while the radiation source is tracked around the patient to minimize skin dosing. The treatment parameters for the radiation treatment plan are derived from the reconstructed measurements used to create an image and then the treatment can be delivered safely with high precision in a minimal number of treatment sessions. The radiation dose enhancement results from interactions between kilovoltage x-rays and the high Z element in contrast agents distributed in a tumor. The invention does not require megavoltage radiation or radiation treatment with a pencil beam. 
     In still further aspects, a radiation source can be mounted in opposition to a digital detector with a C-arm. The apparatus can move about an internal tumor containing a radiation treatment agent and treated to high radiation dose. Alternatively, a CT scanner can be modified with a dual-use collimator to produce a wide-based pyramidal or circular beam and moved around a target for imaging and treatment. A wide detector, or array of detectors, captures the beam for processing. The dose enhancement from the kilovoltage beam&#39;s interaction with contrast is calculated and displayed with treatment planning software. 
     The claimed invention is not limited to the disclosed embodiments, however, as those in the art can readily adapt the description herein to create other embodiments and applications. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
       The construction and usage of embodiments will become readily apparent from consideration of the following specification as illustrated in the accompanying drawings, in which like reference numerals designate like parts, and wherein: 
         FIG. 1  is a diagram illustrating a system according to some embodiments; 
         FIG. 2  is a simplified perspective view of dual-use radiation delivery components according to some embodiments; 
         FIG. 3  is a diagram illustrating elements of a dual-use radiation system according to some embodiments; and 
         FIG. 4  is a diagram illustrating elements of a dual-use radiation system according to some embodiments. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The construction and usage of embodiments will become readily apparent from consideration of the following specification as illustrated in the accompanying drawings, in which like reference numerals designate like parts, and wherein: 
       FIG. 1  is a diagram illustrating a system according to some embodiments. System  1  comprises dual-use radiation source  5  containing dual-use collimators  10  and detector  15 . According to some embodiments, dual-use collimators  10  are usable for creating a diagnostic image and treating an identified lesion according to a radiation treatment plan. As will be described in detail below, the dual-use collimators  10  might be associated with imaging and/or radiation treatment planning software  44 . 
     Radiation source  5  may comprise any currently or hereafter know device that is capable of treating tissue with radiation, e.g., kilovoltage x-rays. The radiation emitted from radiation source  5  is contoured by dual-use collimators  10  that shape the x-rays into a wide pyramidal beam  12 , which is neither a fan beam nor a pencil beam. Opposing the beam is digital detector  15 , which measures and images the beam  12  after in passes through patient  20  and lesion  25 . Radiation source  5  and detector  15  can move about patient  20  but detector  15  is always maintained in a position opposing radiation source  5 . The path about the patient  20  and internal lesion  25  is indicated by arrows  4 . The patient  20  lies on a movable table  30  for positioning during acquisition of the image and better alignment of the target  25  during treatment. The table  30  can move in three-dimensions, i.e., left and right (x-axis), in addition to up and down (y-axis), and in and out of the plane of the drawing (z-axis), to better situate the target  25  relative to the radiation source  5  for treatment. 
     The digital detector  15  may comprise an image intensifier and camera, a flat-panel device using a scintillator layer and solid-state amorphous silicon photodiodes deployed in a two-dimensional array, or any detector system used in CT scanners. The digital detector  15  may also convert x-rays to electrical charge and store it without use of a scintillator layer. In such devices, x-rays are absorbed directly by an array of amorphous selenium photoconductors. The photoconductors convert the x-rays directly to stored electrical charge that comprises an acquired image of a radiation field. Digital detector  15  may also comprise a CCD or tube-based camera. 
     Prior to imaging or treatment with radiation in the kilovoltage energy range, the absorption cross-cross section of the target  25  is enhanced by the administration of a radiation treatment agent  22  containing an element having an atomic weight greater than fifty (U.S. Pat. Nos. 6,125,295 and 6,366,801, and U.S. application Ser. No. 11/758,001). Accordingly, radiation treatment agent  22  may compromise a heavy element-containing compound in some embodiments, e.g., iodine, gold, or bismuth. Since a radiation beam will be more readily stopped by the volume of radiation agent  22  in the target  25 , the painted target  25  will be more damaged than the surrounding normal tissue without the heavy element. The radiation treatment agent  22  is not itself radioactive; it reacts to radiation from radiation source  5 . 
     However, despite the increase in radiation dose in a target  25  as a result of the its uptake of radiation agent  22 , to deliver sufficient radiation dose to safely destroy a pathological lesion anywhere in the body requires kilovoltage x-ray beams  12  aimed at the target  25  from multiple angles. Therefore, the system  1  must be capable of moving the radiation source  5  and digital detector  15  around the patient  20  while keeping the target  25  in the radiation beam  12 . 
     The operator station  40  of system  1  includes computers  41  in communication with a display  42  and an entry device  43  such as a keyboard. The computer  41  may be a dedicated part of system  1  or may be in communication at a distance. The computer  41  may facilitate diagnostic scanning and contain software medium  44  to reconstruct images from data acquired by detector  15 . An operator may employ the operator station  40  to instruct radiation unit  50  to deliver x-ray radiation  12  to the patient  20  for diagnosis or radiation treatment according to a radiation treatment plan in processor  41 . Operator station  40  may also or alternatively be used to generate the radiation treatment plan. In this regard, operator station  40  may generate the treatment plan by importing computed tomography images, or other acquired images, and then executing inverse treatment planning based on the images. The treatment plan may then be exported to an application for controlling radiation unit  50 . 
     Operator station  40  may be located apart from radiation unit  50 , such as in a different room, in order to protect the operator from radiation. It should be noted, however, that the operation of low-voltage radiation systems does not require protective measures to the extent of those required during megavoltage radiation treatment, often resulting in less costly treatment. The operator station  40  can interface with others elements in the dual-use radiation system  1  in some embodiments including radiation source  5  control, dual-use collimator  10  control, CT gantry  7  control, table  30  control and imaging detector  15  control. Computer processor  41  further includes microprocessor and memory. 
     Software medium  44  may design and store a radiation treatment plan in computer-readable and executable formats to calculate the therapeutic effects of radiation treatment with multiple beams  12  in the presence of radiation agent  22 . Such software medium  44 , for a spectrum of beam energies from a particular radiation source  5  will model the dissipation of beam flux  12  by tissue absorption and the dose enhancement due to the interaction with radiation agent  22 . The calculation of radiation dose enhancement in an internal target  25  containing radiation agent  22  following treatment with the beam  12  shaped by dual-use collimator  10  is unique for radiation treatment planning. Other radiation treatment planning accounts for the dose reduction as radiation travels in tissue. 
     System  1  may include less or more elements than depicted in  FIG. 1 . Non-exhaustive examples of such elements include fixed wide collimators, intensity modulation of radiation sources, or other radiation sources. System  1  may also be configured in suitable fashions other than that shown in  FIG. 1 . 
     The elements of system  1  may be associated within a single package by any one or more entities. A manufacturer or reseller of radiation source  5 , dual-use collimators  10 , digital detector  15 , software medium  44 , or treatment table  30  may create system  1  and provide system  1  to entities that deliver radiation treatment. In addition, a manufacturer or reseller may also produce system  1  to work with a particular radiation agent  22 . 
       FIG. 2  is a simplified perspective view of dual-use radiation delivery components  50  according to some embodiments. Dual-use radiation delivery components  50  comprise radiation source  5  and dual-use collimators  10 . According to some embodiment, delivery system  1  is used to deliver radiation to patient  20  according to a radiation treatment plan. The radiation source  5  is a beam-emitting device, such as an x-ray tube for delivering radiation. The radiation may have energies ranging from 18 to 300 keV. The radiation emitted by radiation source  5  may comprise any radiation suitable for data acquisition, imaging and/or treatment according to some embodiments. In some embodiments, the radiation is suitable to produce dose-enhancing effects when used in conjunction with a radiation treatment agent  22  that is capable of treating tissue  25  following received radiation. In general, the x-ray tubes presently in use for imaging have small anodes, which make cooling for a therapeutic load more difficult. However, newer CT tubes have much improved power and cooling capabilities. The radiation source  5  does not produce megavoltage radiation as claimed under U.S. Pat. No. 6,618,467. 
     Radiation source  5  may also include beam-shaping devices such as one or more jaws, collimators, reticles and apertures, including dual-use collimators  10 . In one such embodiment in  FIG. 2 , dual-use collimators  10  contour the beam for diagnosis and/or treatment along the z-axis (the long axis of treatment table  30 ) and either the y-axis (ceiling-floor) or the x-axis (left-right) thus producing a wide-base pyramidal beam  12 . Compared to conventional CT collimation the field is significantly greater in the direction of the z-axis (the long axis of treatment table  30 ) and significantly smaller in either the direction of the y-axis (ceiling-floor) or the x-axis (left-right). In the example given, the shaped beam produces a rectangular field, but in other embodiments the field geometry could be circular, ovoid or polygonal by using secondary blocking  13  with multi-leaf collimation or conical shaping forms. The size and shape of the beam are adjustable, but the size of the beam field at the internal target  25  is 10 mm by 10 mm or greater. The greater field size in the z-axis is critical to rapidly treat lesions greater than 1 cm in that direction. The smaller field size in the y- or x-axis is critical to minimizing the skin dose when treating from multiple directions. Additional optimization of radiation source  5  and dual-use collimators  10  beam output can be achieved by intensity modulation of radiation source  5  current flow and dynamic changes in dual-use collimator  10  position with varying treatment beam  12  positions. The dual-use collimators  10  do not produce a pencil beam as claimed under U.S. Pat. No. 5,008,907. Furthermore, the wider radiation field does not require the internal target  25  to be aligned at the isocenter of an arcing beam. 
       FIG. 3  is a diagram illustrating elements of a dual-use radiation system according to some embodiments. Radiation source  5  and digital detector  15  may be coupled to C-arm  6  so as to face one another irrespective of any movement of the C-arm  6  with respect to its base  8  as shown in  FIG. 3 . In this regard, C-arm  6  is slidably mounted on base  8  and can therefore be moved in order to change the position of radiation source  5  with respect to treatment table  30 . Treatment table  30  may also be adjustable to assist in positioning an internal portion  25  of the patient  20  with respect to the radiation unit  50 . In some embodiments, base  8  includes a high-voltage generator for supplying power used by radiation source  5  to generate kilovoltage radiation. 
     Many C-arm/base configurations may be used in conjunction with some embodiments, including portable configurations, wall or ceiling mounted, or robot mounted configurations. In some embodiments, radiation source  5  with dual-use collimator  10  and digital detector  15  are mounted on robot arms with coordinated movement about patient  20  and internal target  25 . 
       FIG. 4  is a diagram illustrating elements of a dual-use radiation system according to some embodiments. Radiation source  5  with dual-use collimator  10  and digital detector  15  may be coupled in CT scanner  7  so as to face one another irrespective of any movement of CT scanner  7  with respect to the patient  20  and an internal target  25  as shown in  FIG. 4 . In such embodiments, the dual-use collimator  10  replaces conventional diagnostic CT collimation to safely permit diagnostic scanning and therapy. In some embodiments, detector  15  is of adequate size in the z-axis to encompass the larger radiation beam  12 . Diagnostic imaging and radiation treatment are performed by movement of the radiation source  5  with dual-use collimator  10  about the patient  20  and internal target  25 . Images are reconstructed from data gathered by detector  15  with CT software medium  44 . Treatment is performed according to radiation planning software  44  using images of the patient  20  to target a lesion  25  containing radiation agent  22 . The treatment table  30  may also be adjustable in the x-axis in addition to the other dimensions to assist in positioning an internal portion  25  of the patient  20  with respect to the radiation unit  50  according to the radiation treatment plan. In some embodiments, CT scanner  7  includes a high-voltage generator for supplying power used by radiation source  5  to generate kilovoltage radiation.