# Patent

## Title
Method and system of optimized volumetric imaging

## Abstract

A system of performing a volumetric scan. The system comprises a surface of positioning a patient in a space parallel thereto, a plurality of extendable detector arms each the detector arm having a detection unit having at least one radiation detector, and an actuator which moves the detection unit along a linear path, and a gantry which supports the plurality of extendable detector arms around the surface so that each the linear path of each respective the extendable detector arm being directed toward the space.

## Background
RELATED APPLICATIONS
This application is a continuation of U.S. patent application Ser. No. 13/726,316 filed on Dec. 24, 2012, which is a continuation of U.S. patent application Ser. No. 12/792,856 filed on Jun. 3, 2010, now U.S. Pat. No. 8,338,788, which claims the benefit of priority under 35 USC 119(e) from U.S. Provisional Patent Application No. 61/229,549 filed on Jul. 29, 2009.
U.S. patent application Ser. No. 13/726,316 incorporates by reference U.S. Provisional Patent Application No. 61/229,549 filed on Jul. 29, 2009, International Patent Application No. PCT/IL2005/001173 filed on Nov. 9, 2005 (PCT Publication No. WO2006/051531 published May 18, 2006) and International Patent Application No. PCT/IL2006/000834 filed on Jul. 19, 2006 (PCT Publication No. WO2007/010534 published Jan. 25, 2007).
The contents of the above applications are incorporated herein by reference in their entirety.


FIELD AND BACKGROUND OF THE INVENTION
The present invention, in some embodiments thereof, relates to method and system of imaging and, more particularly, but not exclusively, to method and system of medical imaging.
Volumetric scans such as CAT scans, PET scans, CT scans, MRI scans, Ultrasound scans, Laser 3D scanners, and the like are commonly used, particularly in the medical industry, to observe objects within a structure that would otherwise be unobservable. These scans have greatly advanced the capability of professionals such as doctors. Conventional volumetric scan is intended to produce a volumetric image of a large volume of the body at high resolution. The ability to perform a volumetric scan with high resolution requires a large number of detectors, a fine motion control, and abundant processing resources for allowing the acquisition of a high resolution volumetric image in a reasonable time. Furthermore, as the volumetric scan images a relatively large area, such as the torso, the patient radiation dose is relatively high, for example when the volumetric scan is a CT scan.
Usually, volumetric imaging of a body structure is a multi-stage process. First biochemical, radioactive and/or contrast agents may be administered. Then, measurements are taken at a set of predetermined views at predetermined locations, orientations, and durations. Then, the data is analyzed to reconstruct a volumetric image of the body structure and an image of the body structure is formed. The imaging process is sequential, and there is no assessment of the quality of the reconstructed image until after the measurement process is completed. Where a poor quality image is obtained, the measurements must be repeated, resulting in inconvenience to the patient and inefficiency in the imaging process.
The volumetric scan is usually performed by orbiting detectors from multiple directions in order to provide sufficient information to reconstruct a three-dimensional image of the radiation source by means of computed tomography. The detectors are typically mounted on a gantry to provide structural support and to orbit the detector around the object of interest. If the detector is a nuclear medicine detector, such as scintillation detector or CZT detectors, for example Single photon emission computed tomography single photon emission computed tomography (SPECT) and positron emission tomography (PET) systems detector, a collimator that is used to restrict radiation acceptance, or the direction of ray travel, is placed between it and the object being imaged. Typically this collimator is constructed to provide a multiplicity of small holes in a dense, high-atomic-number material such as lead or Tungsten. The rays will pass through the holes if they travel in a direction aligned with the hole but will tend to be absorbed by the collimator material if they travel in a direction not aligned with the holes.
During the last years, a number of non-orbiting tomographic imaging systems have been developed. For example U.S. Pat. No. 6,242,743, filed on Aug. 11, 1998 describes tomographic imaging system which images ionizing radiation such as gamma rays or x rays and which: 1) can produce tomographic images without requiring an orbiting motion of the detector(s) or collimator(s) around the object of interest, 2) produces smaller tomographic systems with enhanced system mobility, and 3) is capable of observing the object of interest from sufficiently many directions to allow multiple time-sequenced tomographic images to be produced. The system consists of a plurality of detector modules which are distributed about or around the object of interest and which fully or partially encircle it. The detector modules are positioned close to the object of interest thereby improving spatial resolution and image quality. The plurality of detectors view a portion of the patient or object of interest simultaneously from a plurality of positions. These attributes are achieved by configuring small modular radiation detector with collimators in a combination of application-specific acquisition geometries and non-orbital detector module motion sequences composed of tilting, swiveling and translating motions, and combinations of such motions. Various kinds of module geometry and module or collimator motion sequences are possible, and several combinations of such geometry and motion are shown. The geometric configurations may be fixed or variable during the acquisition or between acquisition intervals. Clinical applications of various embodiments of the tomography invention include imaging of the human heart, breast, brain or limbs, or small animals. Methods of using the non-orbiting tomographic imaging system are also included.
Another example is described in United States Patent Application 2010/0001200, published on Jul. 1, 2010, which describes an imaging system for radioimaging a region of interest (ROI) of a subject. The system includes a housing, a support structure, which is movably coupled to the housing, and at least one motor assembly, coupled to the housing and the support structure, and configured to move the support structure with respect to the housing. The system also includes at least two detector assemblies, fixed to the support structure, and comprising respective radiation detectors and angular orientators. A control unit drives the motor assembly to position the support structure in a plurality of positions with respect to the housing, and, while the support structure is positioned in each of the plurality of positions, drives the orientators to orient the respective detectors in a plurality of rotational orientations with respect to the ROI, and to detect radiation from the ROI at the rotational orientations. Other embodiments are also described.
SUMMARY OF THE INVENTION
According to some embodiments of the present invention there is provided a system of performing a volumetric scan. The system comprises a surface of positioning a patient in a space parallel thereto, a plurality of extendable detector arms each the detector arm having a detection unit having at least one radiation detector, and an actuator which moves the detection unit along a linear path, and a gantry which supports the plurality of extendable detector arms around the surface so that each the linear path of each respective the extendable detector arm being directed toward the space.
Optionally, the system further comprises a controller for controlling each the actuator to move a respective the detection unit along the linear path according to a scanning pattern.
Optionally, the detection unit comprises a tilting mechanism for tilting the at least one radiation detector in a sweeping motion.
Optionally, the gantry is configured for radially disposing the plurality of extendable detector arms along an arch above the surface.
Optionally, the at least one radiation detector comprises at least one nuclear medicine (NM) detector.
Optionally, each the extendable detector arm comprises an X-ray radiation source and the at least one radiation detector being set to intercept a reflection of X-ray radiation emitted from the X-ray radiation source.
More optionally, the X-ray radiation source is part of the detection unit. More optionally, the at least one radiation detector intercepts both the reflection and Gamma ray radiation emitted from the body of the patient.
More optionally, each the detection unit operates both in a photon counting mode and in a flux measurement mode.
Optionally, the gantry rotates the plurality of extendable detector arms around the body of the patient.
Optionally, the surface is at least one of a horizontal surface or a vertical surface embedded with a plurality of additional radiation detectors.
Optionally, the surface is at least one of a bed, a chair and a wall.
More optionally, at least one of the plurality of detection units comprises a proximity detector which estimates a distance between a tip of a respective the extendable detector arm and the body of the patient, the controller controls each respective the actuator according to respective the distance.
More optionally, at least one of the plurality of detection units comprises a pressure detector which estimates a pressure applied on the body of the patient by a tip of a respective the extendable detector arm, the controller controls each respective the actuator according to respective the pressure.
Optionally, at least one of the plurality of detection units comprises an attenuation correction detector which captures additional radiation emitted from the body of the patient to correct a reconstruction of a volumetric image by radiation intercepted by respective the at least one radiation detector.
More optionally, the attenuation correction detector is an ultrasonic (US) transducer.
More optionally, the system further comprises a breathing detector which monitors thoracic movements of the patient; the controller controls at least one of the plurality of actuators according to the monitoring.
Optionally, the linear path extends from a plane defined by the gantry.
Optionally, the linear path is diagonal to the surface.
More optionally, the actuator rotates each the detection unit around an axis parallel to a respective the linear path.
Optionally, the system further comprises at least one additional gantry each supports a plurality of extendable detector arms around the surface in a similar manner to the manner the gantry supports the plurality of extendable detector arms.
More optionally, the tips of the plurality of extendable detector arms and the plurality of extendable detector arms are extended toward a common axial plane of the body of the patient.
Optionally, the system further comprises at least one tilting motor which tilts at least one of the plurality of extendable detector arms in relation to the gantry.
Optionally, each the detection unit comprises an array of a plurality of radiation detectors, each set to move in sweeping motion.
According to some embodiments of the present invention there is provided a method of performing a volumetric scan that comprises a) providing a surface of positioning a patient in a space parallel thereto, b) linearly moving a plurality of detection units, each having at least one radiation detector, from a plurality of distinct locations along a framework around the surface toward a plurality of points each at a less than a predefined distance from the body of the patient, c) intercepting radiation from the patient using each the at least one radiation detector, and d) reconstructing a volumetric image of at least one part of the patient's body according to the radiation.
Optionally, the method further comprises radially disposing plurality of detection units to a plurality of new locations and repeating the c) and d) from the plurality of new locations.
Optionally, the plurality of points comprises a plurality of points of contact with the body of the patient.
Optionally, the plurality of points comprises a plurality of points of proximity from the body, each the point of proximity being at a distance of less than 5 cm from the body.
Optionally, the distinct locations are at least 5 cm from one another.
Optionally, the intercepting comprises tilting each the at least one radiation detector in sweeping motion at the point of contact.
Optionally, the method further comprises selecting a group of the plurality of detection units according to a dimension of the body of the patient, the linearly moving comprising linearly moving only members the group.
Optionally, the linearly moving comprises, for each the detection unit, detecting a distance from the body of the patient and linearly moving respective the radiation detector according to the distance.
Optionally, the linearly moving comprises, using an actuator to move the detection unit toward the body of the patient until a pressure applied by the actuator is above a threshold.
Optionally, the linearly moving comprises monitoring breathing of the patient and controlling the linear motion according to the monitoring.
Optionally, the system further comprises changing at least one of emission and orientation of the plurality of detection units so as to increase the resolution of the volumetric image in at least one region of interest in relation to other regions of the volumetric image and repeating the b)-d).
According to some embodiments of the present invention there is provided a system of performing a volumetric scan. The system comprises a surface of positioning a patient in a space parallel thereto, a plurality of radiation detectors embedded in the surface and set to intercept radiation emitted from of at least one part of the patient's body, and a reconstruction module which reconstructs a volumetric image of the at least one part according to the intercepted radiation.
Optionally, the system further comprises of actuating unit for actuating the plurality of radiation detectors according to a scanning pattern.
Optionally, the system further comprises a gantry which supports a plurality of additional radiation detectors above the surface, the additional radiation detectors are set to intercept additional radiation emitted from of the at least one part, the reconstruction module reconstructs the volumetric image according to a combination of the intercepted radiation and the intercepted additional radiation.
Unless otherwise defined, all technical and/or scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention pertains. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of embodiments of the invention, exemplary methods and/or materials are described below. In case of conflict, the patent specification, including definitions, will control. In addition, the materials, methods, and examples are illustrative only and are not intended to be necessarily limiting.
Implementation of the method and/or system of embodiments of the invention can involve performing or completing selected tasks manually, automatically, or a combination thereof. Moreover, according to actual instrumentation and equipment of embodiments of the method and/or system of the invention, several selected tasks could be implemented by hardware, by software or by firmware or by a combination thereof using an operating system.
For example, hardware for performing selected tasks according to embodiments of the invention could be implemented as a chip or a circuit. As software, selected tasks according to embodiments of the invention could be implemented as a plurality of software instructions being executed by a computer using any suitable operating system. In an exemplary embodiment of the invention, one or more tasks according to exemplary embodiments of method and/or system as described herein are performed by a data processor, such as a computing platform for executing a plurality of instructions. Optionally, the data processor includes a volatile memory for storing instructions and/or data and/or a non-volatile storage, for example, a magnetic hard-disk and/or removable media, for storing instructions and/or data. Optionally, a network connection is provided as well. A display and/or a user input device such as a keyboard or mouse are optionally provided as well.



BRIEF DESCRIPTION OF THE DRAWINGS
Some embodiments of the invention are herein described, by way of example only, with reference to the accompanying drawings. With specific reference now to the drawings in detail, it is stressed that the particulars shown are by way of example and for purposes of illustrative discussion of embodiments of the invention. In this regard, the description taken with the drawings makes apparent to those skilled in the art how embodiments of the invention may be practiced.
In the drawings:
FIG. 1 is a sectional schematic illustration of a volumetric scanner having a gantry radially supporting a plurality of extendable detector arms, according to some embodiments of the present invention;
FIG. 2A is a sectional schematic illustration of the volumetric scanner where a disposition of one of the extendable detector arms along an arch is depicted, according to some embodiments of the present invention;
FIGS. 2B-2D are sectional schematic illustrations of a plurality of detection units mounted on a circular gantry which may change the proximity of detection units from the body of a patient, according to some embodiments of the present invention;
FIG. 3 is a lateral view of a portion of an extendable detector arm, such as depicted in FIG. 1, along an axis that is perpendicular to the longitudinal axis of the patient bed 85, according to some embodiments of the present invention;
FIG. 4 is a lateral schematic illustration of an exemplary gantry and a patient horizontally positioned on a patient bed, according to some embodiments of the present invention;
FIG. 5A is a sectional schematic illustration of an exemplary detection unit in a tip of an extendable detector arm, according to some embodiments of the present invention;
FIG. 5B is a sectional schematic illustration of the exemplary detection unit in the tip of an extendable detector arm of FIG. 5A a set of rollers are mounted on the tip, according to some embodiments of the present invention;
FIG. 6A is a schematic illustration of an arrangement having a CT scanner and the volumetric scanner, according to some embodiments of the present invention;
FIG. 6B a sectional schematic illustration of a circular gantry, according to some embodiments of the present invention;
FIG. 7 is a sectional schematic illustration of an exemplary back surface, along its latitudinal axis, below a pad on which a patient lies, according to some embodiments of the present invention;
FIG. 8 is a sectional schematic illustration of a volumetric scanner as depicted in FIG. 1 with a patient bed as depicted in FIG. 7, according to some embodiments of the present invention;
FIG. 9 is a schematic illustration a volumetric scanner having a plurality of extendable detector arms each with a plurality of detection units, according to some embodiments of the present invention;
FIG. 10 is a schematic illustration of a volumetric scanner having a plurality of gantries, according to some embodiments of the present invention; and
FIG. 11 is a flowchart of a method of performing a volumetric scan, according to some embodiments of the present invention; and
FIG. 12 is another flowchart of a method of performing a volumetric scan, according to some embodiments of the present invention.



DESCRIPTION OF EMBODIMENTS OF THE INVENTION
The present invention, in some embodiments thereof, relates to method and system of imaging and, more particularly, but not exclusively, to method and system of medical imaging.
According to some embodiments of the present invention there is provided a system of performing a volumetric scan of at least a part of a body of a patient, such as a volumetric scanner, using a plurality of radiation detectors which are moved toward the body of the patient, and are capable of local translation or rotation, optionally separately.
The system includes a patient surface of positioning the patient in a space parallel thereto. The patient surface may be adjusted to support standing patients, laying patients, seating patients, and/or leaning patients. For example, the surface may be a horizontal alignment surface, such as a patient bed, a vertical alignment surface, such as a wall or a back of a chair and the like.
The patient surface is optionally embedded with a plurality of radiation detectors intercepts radiation emitted or reflected from the patient, for example as shown at FIG. 7. In other embodiments, the radiation detectors are placed in the patient surface that is placed below or in a pad on which a patient lies.

For brevity radiation emitted, transmitted through or reflected from the patient may be referred to herein as radiation emitted from the patient. The system further includes a plurality of extendable detector arms. Each extendable detector arm has a detection unit with one or more radiation detectors, such as nuclear medicine detectors, and an actuator that moves the detection unit along a linear path toward and from the body of the patient. The system further includes a gantry, optionally annular or semiannular, which supports the arms around the patient. In use, the patient may horizontally positioned on the surface, and the extendable detector arms may be used for bringing the detection units to points in a predefined distance from the body of the patient and/or to points of contact with the body of the patient. The projection of radiation, such as gamma radiation, which is intercepted by the detectors of the detection units allow reconstructing a volumetric image. Optionally, each detection unit includes a radiation source, such as an X-ray source that allows transmitting radiation into the body of the patient. In such embodiments, a volumetric image may be reconstructed according to both gamma and x-ray radiation which is emitted and reflected from the body of the patient. Optionally, the extendable detector arms and/or the gantry may be rotated tilted, and/or moved along the patient surface according to a scanning pattern and/or user instructions.

Optionally, the number of extendable detector arms which are used for reconstructing the volumetric image dependents on the dimension of the patient. In such an embodiment, a limited number of extendable detector arms may be used for imaging a thin patient and a larger number of extendable detector arms may be used for imaging an obese patient. Optionally, a number of gantries with extendable detector arms are used for reconstructing a volumetric image of a patient. In such an embodiment, a single gantry may be used for imaging a thin patient and a number of gantries may be used for imaging an obese patient.
According to some embodiments of the present invention, there is provided a system of performing a volumetric scan. The system includes a surface of positioning a patient in a space parallel thereto, such as a bed, and a plurality of radiation detectors which may be embedded into the surface, which may be placed below a pad on which the patient lies, and set to intercept radiation emitted from of at least one part of the patient's body, for example and as outlined above and described below. The system further includes a reconstruction module that reconstructs a volumetric image of the at least one part according to the intercepted radiation.
Before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not necessarily limited in its application to the details of construction and the arrangement of the components and/or methods set forth in the following description and/or illustrated in the drawings and/or the Examples. The invention is capable of other embodiments or of being practiced or carried out in various ways.
Reference is now made to FIG. 1, which is a sectional schematic illustration of a system, such as a volumetric scanner 81, for example a nuclear medicine (NM) scanner, having a gantry 80 radially supporting a plurality of extendable detector arms 83, optionally having their tips directed toward a common volumetric area above patient's bed 805, according to some embodiments of the present invention. Optionally, the volumetric scanner 81 allows capturing a Clinically-Valuable Image of the patient, as defined below.
As used herein, an extendable detector arm means having a detector arm having a varying length. The gantry 80 is optionally an annular and/or semiannular frame that is designed to be placed around a surface 85 of positioning a patient for scanning in a space, such as a bed, referred to herein as a patient surface, for example as shown in FIG. 1. Each extendable detector arm 83 may include a linear actuator 86 and a detection unit 84 that is connected to its tip for intercepting radiation from the scanned patient. For brevity, the term patient may be used to describe any body portion of a patient, for example one or more organs and/or a portion of an organ. The detection unit 84 includes one or more radiation detectors, such as semiconductor radiation detectors, for example nuclear medicine (NM) detectors, for instance cadmium zinc telluride (CZT) detectors. The linear actuator 86 is designed to linearly maneuver the detection unit 84 toward and from a location in a space bounded or otherwise defined by gantry 80. Optionally, the linear actuator 86 is mechanical actuator that converts rotary motion of a control knob into linear displacement, a hydraulic actuator or hydraulic cylinder, for example a hollow cylinder having a piston, a piezoelectric actuator having a voltage dependent expandable unit, and/or an electro-mechanical actuator that is based on an electric motor, such a step motor and the like. The linear actuators 86 of the extendable detector arms 83 are connected to a controller 82 which converts digital signals of a scanning computing unit 82 into electronic signals necessary to control it. The control of each linear detector actuator 83 is performed according to a volumetric scanning pattern calculated and/or controlled by the scanning computing unit 82 and/or attenuation correction/scatter corrections (ACSCs), for example corrections of breathing motions, optionally calculated according to feedback from one or more sensors, such as position sensors, which sense the actual location of the tip of the respective extendable detector arm 83. As the extendable detector arms includes only some of the total detection units 84 which are used in the volumetric scanner 81, motion control which require about 1 Kg moving force or less may be enabled. As such, they do not apply extensive force on the patient and may easily get in contact with the patient's skin by using linear actuator 86, such as a pneumatic actuator.
When a patient 88 is positioned horizontally on the patient surface 85, the controller 82 instructs the linear actuators 86 to extend toward the patient's body in a space above the patient surface 85, for example along the linear axes depicted in FIG. 1, such as numeral 90. Optionally, the instructions are provided according to a volumetric scanning pattern calculated and/or controlled by a scanning computing unit 87. Optionally, contrast materials, contrast agents and/or contrast mediums, are injected to the patient 88 before the scanning process. The contrast material may include any internally administered substance that has, when imaged by the CT scanner, a different opacity from soft tissue on computed tomography, for example Barium, water, Iodine, and/or Sterile saline.
Optionally, some or all of the extendable detector arms 83 have a proximity detector, for example as shown at 89, such as an electrostatic touch sensor, a capacitive, an infrared (IR) detector or an acoustic proximity detector, such as an ultrasonic (US) transducer. The proximity detector 89 is electrically connected to the controller 82 so as to allow the controller 82 to receive its feedback. The proximity detector 89 indicates when the tip of the extendable detector arms 83 and/or the detection unit 84 is in a certain distance from the body of the patient 88. Optionally, the controller instructs the extending of the extendable detector arms 83 until the proximity detector 89 feedback indicates that the tip of the extendable detector arms 83 is in touch with the body of the patient 88. Optionally, any group of extendable detector arms 83 may be extended together, for example a group of 1, 2, 3, 4, 5, 6, 7, and 8 extendable detector arms 83. Optionally, the proximity detector 89 includes a pressure sensor which indicates when the tip of the extendable detector arm 83 applies a certain amount of pressure on the body of the patient. In such a manner, the proximity detector 89 can indicate that the tip of the extendable detector arm 83 is held firmly against the body of the patient. Optionally, the pressure applied by each extendable detector arm 83 is no more than 1 kilogram (Kg). Optionally, the proximity detector 89 is placed about 1 centimeter (cm) from the tip of the extendable detector arm 83.
Optionally, some or all of the extendable detector arms 83 have a breathing detector, such as an US transducer which monitors the breathing of the patient 88 for example by monitoring her thoracic movements. In such an embodiment, the extending of the extendable detector arms 83 may be coordinated with the breathing cycle of the patient. Optionally, the same detector is used as a proximity detector and as a breathing detector, for example a US transducer. Optionally, the same detector is also used as a pressure detector.
Optionally, as shown at FIG. 2A, each one of the extendable detector arms 83 may be radially disposed 71 along an arch or a perimeter of a circle centered at a location above the patient surface 85. Optionally, any group of extendable detector arms 83 may be radially disposed 71 together. The movement of the extendable detector arm 83 is optionally defined by a path, such as a groove, in the gantry 80 and controlled by the controller 82, for example according to a volumetric scanning pattern calculated and/or controlled by the scanning computing unit 82. Optionally, one or more motors actuate the movement of each extendable detector arm 83 along the arch or perimeter according to the outputs of the controller 82.
Optionally, the gantry 80 may be rotated tilted, and/or moved along the patient surface 85 according to the outputs of the controller 82 and/or user instructions.
According to some embodiments of the present invention, the gantry 80 is circular, for example as shown at FIG. 6B. Optionally, the volumetric scanner 81 allows capturing a Clinically-Valuable Image of the patient, as defined below. In such an embodiment, the gantry may be used to rotate the extendable detector arms 83 around the patient 88. Optionally, the extendable detector arms 83 are rotated while being in contact with the body of the patient 88 and/or in proximity to the body of the patient 88.
Reference is now made to FIGS. 2B-2D, which are sectional schematic illustrations of a circular gantry 80 having a plurality of detection units 84, according to some embodiments of the present invention. Though the detection units 84 are depicted as circular elements, they may have various forms and may be actuated as described above in relation to FIGS. 1 and 2. In FIG. 2B, the detection units 84 are located away from the body of the patient 88. FIG. 2C depicts the detection units 84 when they are located in a plurality of contact points with the body of the patient 88 or in a plurality of proximity points from the body of the patient 88.
In FIG. 2D, only some of the detection units 84 are located in a plurality of contact points with the head of the patient 88 or in a plurality of proximity points from the head of the patient 88. As further described below, a group of detection units 84 may be used to image thin patients and/or organs with limited perimeters while others are idle. In such a manner, the number of detection units 84 which are used in each scan is dynamic, allowing using the same scanner for scanning various organs and/or patients from a plurality of contact and/or proximity points with and/or from the patient 88. FIGS. 2B-2D further depict exemplary perimeters and radiuses of the volumetric scanner 81.
Reference is now also made to FIG. 3, which is a lateral view of an extendable detector arm, such as 83 in FIG. 1, along an axis that is perpendicular to the longitudinal axis of the patient surface 85, according to some embodiments of the present invention. Optionally, as shown at FIG. 2A, the extendable detector arm 83 moves along the longitudinal axis of the patient surface 85, for example along the axis depicted in 61, or swings so that the tip of the extendable detector arm 83 scans the longitudinal axis of the patient surface 85, for example swings along a swing axis depicted in 62 or 63. Optionally, the extendable detector arm 83 is biased in an angle of about 2, 4, 5, 8, 10, 15, 30 degrees or any intimidate or higher degree in relation to a plane traversing the supporting framework 80, creating lateral translations of 1, 2, 5, 10 mm and/or greater, such as 2-25 cm or more, for example, 3, 4, 5, 8, 12, and the like).
The movement of the extendable detector arm 83 is optionally defined by a path, such as a groove, in the gantry 80 and controlled by the controller 82, for example according to a volumetric scanning pattern calculated and/or controlled by the scanning computing unit 87. Optionally, one or more motors actuate the swing of the extendable detector arm 83 and/or the movement thereof along the longitudinal axis of the patient surface 85 according to the outputs of the controller 82.
Optionally, some or all of the extendable detector arms 83 are rotated around their own axes, for example along the vector shown at 154. Optionally, the rotation is controlled by the controller 82, for example according to a volumetric scanning pattern calculated and/or controlled by the scanning computing unit 87.
Reference is now made to FIG. 4, which is a lateral schematic illustration of an exemplary gantry, such as 80, and a patient surface, such as 85, according to some embodiments of the present invention. FIG. 4 depicts optionally motion vectors of the gantry 80. The gantry 80 may be designed to move along these motion vectors during a scanning process, for example according to a volumetric scanning pattern calculated and/or controlled by the scanning computing unit 87. Optionally, one or more motors are connected to the gantry 80 to facilitate the movement thereof along these vectors.
Optionally, the gantry 80 moves along the patient surface 85, for example along the vector shown at 151. Optionally, the gantry 80 tilted about an axis perpendicular to the longitudinal axis of the patient surface 85, for example along the vector shown at 152. Optionally, the gantry 80 rotates around a longitudinal axis of the patient surface 85, for example along the vector shown at 153. Optionally, the patient surface 85 moves through the gantry 80.
Reference is now made to FIG. 5, which is a sectional schematic illustration of an exemplary detection unit 84 in a tip of an extendable detector arm 83, according to some embodiments of the present invention. As shown at FIG. 5, the detection unit 84 includes a tilting mechanism 401 for tilting one or more radiation detectors such as semiconductor radiation detectors 402. The tilting mechanism 401 optionally includes a mount to which the radiation detectors 402 are connected. This tilting motion allows the semiconductor radiation detectors to scan a portion of the patient 88 in sweep motions, for example as described in International Application No. IL2005/001173, filed Nov. 19, 2005, which is incorporated herein by reference. Optionally, the semiconductor radiation detectors 402 sweep among a number of positions. Optionally, the angular deviation between the different positions is about 1⁄4, 1⁄3, 1⁄2 and/or 1 degree. Optionally, the positions are spread over an angular opening of between about 10 and 120 degrees. Optionally, the angular opening and/or number of positions depend on the ROI, creating for example 10, 20, 30, 50, 100, 200, 500 or any intermediate or smaller number of positions for each radiation detector 402 which sweeps in a scan pattern. Optionally, the radiation detector 402 remains in each angular position for a time period of about 0.1 second, 0.2 second, 0.5 second, 0.8 second, 1 second, 1.5 second 3 sec, and 5 sec. Alternatively the radiation detector 402 sweeps in a continuous motion.
Optionally, the tilting mechanism 401 includes a mount hinged on a rotating shaft 405 and a motor for actuating the mount. The motor is optionally controlled by the controller 82. For example, the semiconductor radiation detectors 402 are 16×16 pixilated, 2.54×2.54 mm in size, CZT arrays. Optionally, the detector is fitted with a collimator, such as a parallel hole collimator 403. The collimator 403 defines the solid angle from which radioactive emission events may be detected. Optionally, different semiconductor radiation detectors 402 have collimators with different characteristics. In such an embodiment collimators of high and low resolutions may be combined. In such a manner, high and/or resolution images of the patient's body or any portion thereof may be taken using the volumetric scanner 81. Optionally, the length of the collimation size of the collimators is between about 2 cm and about 3 cm and their width is between about 2 mm and about 3 mm.
As described above, the extendable detector arm 83 has a proximity detector 89. Additionally or alternatively, the extendable detector arm 83 may further include one or more attenuation correction transducers 413, such as US transducers. Optionally, the ACSCs of each detection unit 84 is performed based on the output of an adjacent attenuation correction transducer 413 in the extendable detector arm 83, for example as described in U.S. Pat. No. 7,652,259, filed on Apr. 11, 2003, which is incorporated herein by reference. The ACSC allows correcting the effect of bodily movements, for example breathing motion.
Optionally, a pad 406, such as a gel pad, for example an ultrasonic coupling gel pad, is attached to the tip of the extendable detector arm 83 and/or to the size of the extendable detector arm 83. The pad protects the patient's skin from being abraded by the extendable detector arm 83 and optionally provides an ultrasonic coupling medium for the US transducers. Additionally or alternatively, as shown at FIG. 5B, one or more rollers 407, such as wheels or balls, are attached to the tip of the extendable detector arm 83. The rollers allow maintaining the tip of the extendable detector arm 83 close to the skin of the patient without rubbing so as to protect, or further protect, the patient's skin from being abraded by the extendable detector arm 83. The one or more rollers 407 also allow rotating the extendable detector arm 83 along the contour of the body of the patient 88 while the tip of the extendable detector arm 83 is in contact with the body of the patient 88.
According to some embodiments of the present invention, the volumetric scanner 87 includes a positioning unit which estimates the location of the patient before and/or during the scan. Optionally, the positioning unit includes one or more image sensors, such as one or more CCD cameras and an image processing module which estimates the contour of the body of the patient 88 according to an analysis of the output of the one or more CCD cameras and instructs the extendable detector arm 83 to follow a certain pattern according to the analysis. Optionally, the positioning unit includes one or more proximity sensors.
According to some embodiments of the present invention, some or all of the extendable detector arms 83 includes an X-ray source 408, such as a calibrated or uncalibrated solid radioactive source, an X-ray tube, for example a commercially available tungsten tube, and an anode tube. In such an embodiment, the detection unit 84 may be used for capturing both X-rays emitted from the X-ray source and Gamma ray from the body of the patient, for example from radioactive tracer material, also known as radiopharmaceuticals. In such an embodiment, the acquired X-ray and Gamma ray projections, optionally from detection units 84 in multiple extendable detector arm 83 are used to reconstruct an image, such as a 3D image or a 4D Image, for example by applying known tomographic reconstruction algorithms. This image may then be manipulated to show thin slices along any chosen axis of the body, similar to those obtained from other tomographic techniques, such as MRI, CT, and PET. Optionally, the X-rays and the Gamma ray are captured in different radiation interception sessions. In a first group of radiation interception sessions Gamma-rays are captured and the X-ray source is idle. In a second group of radiation interception sessions X-rays which are emitted from the X-ray source are captured. The time taken to obtain the X-ray and Gamma ray projection of in each angle and/or session may be variable, for example 2 minutes per session. Optionally, the X-Ray flux generated by the X-ray source is adapted to allow the detectors of the detection units 84 to function both as SPECT detectors and CT detectors. In such embodiments the X-Ray flux allows the detectors to perform photon counting, for example at a rate of 80,000 counts per second.
By using X-ray source, the volumetric scanner 81 may be used for computerized tomography (CT). As the detection units 84 and the X-ray source 408 are placed in proximity to the body of the patient 88, the effect of bodily movements has less affect on the reconstructed image. Moreover, the force applied by the plurality of extendable detector arms 83 holds, or sustainably holds the body of the patient 88 in place and limits its movement space. In such a manner, the patient moment has less effect on the reconstructed image. In such embodiments, the period of each scanning session, in which a slice is scanned, is set so that the time spent for scanning each slice is roughly equivalent for reconstructing a CT and SPECT images. Optionally X-ray projections are used for attenuation and/or scatter corrections of Gamma ray projections and vice versa.
Optionally, the CT to SPECT information is used in real time (one affect the scan of the other during the acquisition.
Optionally, the X-Ray source allows acquiring volumetric images by when extremely low dose are used. These images may have low resolution and therefore may be used for general anatomy/body contouring/motion correction, for example breathing correction, gating and the like.
Reference is now made to FIG. 6A, which is a schematic illustration of an arrangement which includes a CT scanner 251, as known in the art, and the volumetric scanner 81 which is placed abject thereto, for example as depicted in FIG. 1, according to some embodiments of the present invention. In such an embodiment, the patient 88 may be simultaneously imaged using by the CT scanner 251 and the volumetric scanner 81. Optionally, the scanning period of the CT scanner 251 and the volumetric scanner 81 is similar, for example about 2 minutes.
Reference is now made to FIG. 7, which is a sectional schematic illustration of an exemplary back surface 185, along its latitudinal axis, according to some embodiments of the present invention. Optionally, the back surface 185, which I optionally placed below a pad 186 for lie on, allows capturing a Clinically-Valuable Image of the patient, for example as defined below. The exemplary back surface 185 includes a plurality of detection units 501. Optionally, each detection units as defined above, for example in relation to FIG. 5. Each one of the detection units 501 is connected to a controller and designed to capture X-ray and/or Gamma ray projections. Optionally, the patient surface 185 is the surface on which the patient lies. Optionally, as shown at FIG. 8, the back surface 185 is combined with the volumetric scanner 81 described in FIG. 1. In such an embodiment, the detection units 501 which are embedding in the back surface 185 are used to capture projection from the back side of the patient 88, facilitating a more robust reconstruction of the patient body and/or the patient's back. Optionally, in use, the bed is moved with the patient in and out of one or more gantries which support the aforementioned radiation detectors. In such an embodiment, the back surface 185 may remain in place while the bed moves.
Optionally, the detection units 501 are connected to one or more motors that allow changing their position in relation to the patient. In such a manner, the detection units 501 may be redistributed in the back surface 185 or therebehind after the patient is positioned horizontally thereon. Optionally, the detection units 501 are connected controlled according to the outputs of the controller 82, for example according to a volumetric scanning pattern defined by the scanning computing unit 87.
Reference is now made to FIG. 9, which is a schematic illustration a volumetric scanner 81 having a plurality of extendable detector arms 683 each with a plurality of detection units, for example as shown at 684, according to some embodiments of the present invention. In this embodiment three extendable detector arms 683 are used for covering the patient's body together with the exemplary back surface 185 depicted in FIG. 7, each from a different side. Optionally, only the front extendable detector arm 683 has a plurality of detection units 684. Optionally, the volumetric scanner 81 allows capturing a Clinically-Valuable Image of the patient, as defined below.
According to some embodiments of the present invention, the number of extendable detector arms 83, which are used during a scan, is determined according to the shape and/or dimension of the patient's body and/or the organ which is about to be scanned, for example according to an estimation of the perimeter of patient at the axial plane which is about to be scanned. Optionally, the estimation is made using image processing techniques, for example by analyzing an image of the patient captured by an image detector and/or according to the outputs of some or all of the proximity detectors. For example, four extendable detector arms 83 may be used for imaging a body of a child, a thin patient, and/or a limb of the patient, and six extendable detector arms 83 may be used for imaging a body of an obese patient. In another example, four extendable detector arms 83 may be used for imaging the brain of a patient, creating a cerebral volumetric image, for example as shown in FIG. 2D, and six extendable detector arms 83 may be used for imaging the thorax of the patient.
According to some embodiments of the present invention, the radiation detectors of the detection unit 84 are set work both in a photon counting mode and in a flux measurement mode. Optionally, the detection unit 84 changes its working mode intermediately or sequentially. For example, one or more of the detection units 84 may be set to intermittently intercept Gamma radiation emitted from Tc99m at between about 130 Kilo electronvolt (KeV) and about 150 KeV and X-ray radiation from the body of the patient 88 at about 200 KeV. In such a manner, an energy window of between about 150 KeV and about 250 KeV may be used for detecting X-ray photons and separated them from Gamma ray photons. As such photons include relatively low scattering, the quality of the X-ray based image is relatively high. Optionally, the modes change every second such that in one second X-ray is intercepted and evaluated and in the following Gamma-ray is intercepted and evaluated. Optionally, a number of X-ray transmissions are performed in each X-ray session, optionally one every 0.1 second.
Optionally, the radiation detectors are optimized to measure the total flux of photons rather than being optimized for short acquisition with high flux of photons where each photon is characterized. In such embodiments, scatter affects the image. Optionally, the overall NM acquisition time is reduced to a scale of between about 1 minute and about 2 minutes for a certain region or less. In such a manner, the accuracy of the image registration may be increased, the number of used detectors may be reduced. By selecting an energy window, as described above, and checking it for each photon, photons may be filtered with high probability of being scattered from a lateral origin.
It should be noted that when the intercepted radiation is X-ray radiation, the X-ray source may be as depicted in numeral 408 of FIG. 5 and/or from an X-ray source placed in the gantry, for example as shown in FIG. 6B. The detection units may be activated in any of the aforementioned modes, separately and/or jointly, in any stage.
According to some embodiments of the present invention, a number scanning sessions are performed by the extendable detector arms 83. In such an embodiment, a group of extendable detector arms 83 is used to image the body of the patient 88 in a number of consecutive sessions. In each consecutive session other portions of the patient's body are scanned. In such an embodiment, patients in various sizes may be scanned using a limited number of extendable detector arms 83. For example, four extendable detector arms 83 may be used for imaging a body of a child, a thin patient, and/or a limb of the patient in a single session and a body of an obese patient in two or three sessions. Though this process may increase the time it takes to scan an obese patient, it allows using a device with less extendable detector arms 83.
According to some embodiments of the present invention, the back surface 185, or any other surface on which the patient is placed, is set to be vertically actuated, brings the patient's body closer to the detection units 84, for example to the tips of the extendable detector arms 83.
Reference is now also made to FIG. 10, which is a schematic illustration of a volumetric scanner 81 having a plurality of gantries 800, each optionally defined as gantry 80 of FIG. 1, according to some embodiments of the present invention. Optionally, the number of used gantries 800 is determined according the shape and/or dimension of the patient's body, for example according to an estimation of the perimeter of patient. For example, a single gantry 800 is used for imaging a body of a child, a thin patient, and/or a limb of the patient, and two or more gantries 800 may be used for imaging a body of an obese patient. Optionally, the gantries 800 are used for imaging parallel portions of the patient's body 88. Optionally, the extendable detector arms 83 of different gantries 800 are tilted to image a common portion of the patient's body 88. In such an embodiment the tip of the extendable detector arms 83 may intertwine along a common plane when they are extended to by in touch with the patient's body. For example, extendable detector arms 83 of a first gantry may be from two sides of an extendable detector arm of a second gantry. Optionally, each one of the gantries 800 is synchronized with one or more detection units 501 which are embedded in the patient surface, for example mounted in a surface below a mattress of a patient bed, for example as shown in FIG. 7.
The extendable detector arms 83 allow directing the detection units 84 to face different areas of the patient surface. Rather than facing the geometrical center of a space that is bounded by the gantry 80, the detection units 84 may be directed to face a selected region of interest which is outside of the bounded space.
Reference is now also made to FIG. 11, which is a flowchart of a method of performing a volumetric scan 200, according to some embodiments of the present invention. Optionally, the volumetric scan allows capturing a Clinically-Valuable Image of the patient, as defined below. First, as shown at 201 a surface of positioning a patient in a space parallel thereto is provided, for example the patient surface 85. In use, the patient lies down on the patient surface 85. Then, as shown at 202, a plurality of radiation detectors, such as the detectors in the detection units 84, are linearly extended toward a plurality of points of contact on the body of the patient and/or a plurality of points of proximity in relation to the body of the patient, for example by the extending of the linear actuators 86 from a plurality of distinct locations around the surface 85, on a framework, such as the gantry 80. Optionally, a point of proximity is defined a location from which the distance to the body of the patient is less than 5 cm, for example 1 cm, optionally 0.
Optionally, these distinct locations are apart from one another, for example 5 centimeter (cm) apart from one another, 10 cm apart from one another, 15 cm apart from one another or any intermediate or greater distance. Optionally, the extending length and/or angle of the extendable detector arms 83 is set according to a volumetric scanning pattern, for example controlled according to the controller 92 as defined above. Now, as shown at 203, radiation from the patient is intercepted by the plurality of radiation detectors. The radiation may be gamma ray and/or X-ray radiation, for example as outlined above. This allows, as shown at 204 reconstructing a volumetric image of one or more parts of the patient's body, for example using known SPECT, PET and/or CT imaging reconstruction techniques, for example as described in International Application No. IL2005/001173, filed Nov. 19, 2005, which is incorporated herein by reference.
FIG. 12 is another flowchart of a method of performing a volumetric scan, according to some embodiments of the present. Blocks 201-204 are as depicted in FIG. 11, however FIG. 12 further depicts blocks 210 and 211 in which the detection units 84 are optionally pulled from the points of contact and/or points of proximity and rotated to allow repeating 202-203 from other points of contact and/or points of proximity. The rotation may be performed by rotating the gantry 80 on which the detection units 84 are mounted. Optionally, the volumetric scan allows capturing a Clinically-Valuable Image of the patient, as defined below.
Optionally, as shown at 212, a region of interest is calculated, or recalculated, according to data in the image reconstructed in 211. In such an embodiment, the orientation of the extendable detector arms 83 and/or emission of the X-ray source 408 of some or all of them may be changed according to data in the image reconstructed in 211, for example a characteristic of pathological pattern. The orientation and/or emission of the detectors may be adjusted according to the new region of interest, for example to optimize the scan thereof. This process may be iteratively repeated, concentrating the imaging effort in the changing region of interest.
Optionally, the volumetric scanning pattern is adapted according to data that is captured and analyzed during the scan. In such an embodiment, suspected pathological sites may be detected by analyzing images which are substantially constantly reconstructed during the scan. These images, which are reconstructed based on a limited scanning data, allow capturing an image of a region of interest, which optionally includes a suspected pathological site that is indicative of abnormal cellular composition, cellular growth, fractures, lesions, tumors, hematomas and the like.
Additionally or alternatively, the scanning is adapted to focus on a predefined region of interest. Optionally, predefined region of interest is defined automatically and/or manually according to medical information that is received about the patient, for example similarly to the described in International Patent Application Publication No. WO2008/075362 published on Jan. 26, 2008, which is incorporated herein by reference. As used herein, medical information means, inter alia, information which is related to the patient, such as laboratory results, therapeutic procedure records, clinical evaluations, age, gender, medical condition, ID, genetic information, patient medical record, data indicating of metabolism, blood pressure, patient history, sensitivities, allergies, different population records, treatment methods and the outcome thereof, epidemiologic classification, and patient history, such as treatment history. In such embodiments, the orientation of the directable detectors may be changed in a manner that they are facing toward a region of interest of the patient, for example a known location of a tumor and/or a fracture. The coordinates of the location may be gathered by analyzing the medical information, for example using image processing techniques and/or manually inputted by the system operator and/or caretaker.
Additionally or alternatively, the intensity of the radiation that is emitted by the X-ray source 408 may be changed for example reduced and/or intensified during the volumetric scan. In such a manner, the radiation dose per volumetric scan may be reduced. The emission change reduces the total amount of the radiation that is absorbed by the patient and/or allows avoiding some or all of the redundant emissions. For example, instead of creating a high resolution volumetric CT image of the torso by irradiating the patient, from a plurality of angles, with fluxes which are high enough to overcome all the possible obstacles, for example ribs, initial scanning sessions and/or received medical information are used for identifying these obstacles so as to reduce the emission in areas in which they are present. Then, sideway views, optionally unradial, are taken to complete the missing data. In such a manner, data from a low-flux beam that would go radially towards the obstacle is compensated by either temporarily increasing the flux in an unblocked area and/or by taking additional side views that pass toward the region of interest.
According to some embodiments of the present invention, the orientation of the extendable detector arms 83 and/or emission of the X-ray source 408 of some or all of them may be changed according to characteristics of the region of interest and/or the location thereof. The characteristics can affect area to be scanned, for example the scanning speed, the contrast martial flux and/or wait time, the estimated scatter, attenuation, and/or resolution and the like. All these may be automated for that purpose, save time, and improve quality. The orientation and/or emission of the detectors may be adjusted according to characteristics of a suspected abnormality and thus optimizing the actual scan of the region of interest. For example, a change in an estimated anatomy, physiology, and/or metabolism may be detected during the performance of the scan and taken into account. The orientation and/or emission of the detectors may be changed to acquire more data pertaining to the region of interest and/or the specific suspected pathological sites.
According to some embodiments of the present invention, the orientation of the extendable detector arms 83 and/or emission of the X-ray source 408 of some or all of them may be changed so as to reduce the radiation that is transmitted via and/or toward radiation sensitive areas, such as the gonads, the eyes, the spinal cord, the salivary glands and/or breasts. In such an embodiment, the radiation sensitive areas are detected either in advance or in the initial scanning sessions. Then, the detectors are directed to avoid transmitting radiation toward the radiation sensitive areas and/or to reduce the intensity of the emission transmitted toward the radiation sensitive areas.
In such an embodiment, the detection units 84, and their radiation, are primarily focused on the region of interest. In such a manner, the focusing on one or more regions of interest may continuously improved, allowing focusing the resources on an area that matters the most for the diagnosis of the medical condition of the patient.
Definition of a Clinically-Valuable Image
In consequence to the features described above, the volumetric scanner 81 is capable of producing a “clinically-valuable image” of an intra-body region of interest (ROI) containing a radiopharmaceutical, while fulfilling one or more of the following criteria:

    1. the volumetric scanner 81 is capable of acquiring at least one of 5000 photons emitted from the ROI during the image acquisition procedure, such as at least one of 4000, 3000, 2500, 2000, 1500, 1200, 1000, 800, 600, 400, 200, 100, or 50 photons emitted from the ROI. In one particular embodiment, the volumetric scanner 81 is capable of acquiring at least one of 2000 photons emitted from the ROI during the image acquisition procedure;
    2. the volumetric scanner 81 is capable of acquiring at least 200,000 photons, such as at least 500,000, 1,000,000, 2,000,000, 3,000,000, 4,000,000, 5,000,000, 8,000,000, or 10,000,000 photons, emitted from a portion of the ROI having a volume of no more than 500 cc, such as a volume of no more than 500 cc, 400 cc, 300 cc, 200 cc, 150 cc, lOOcc, or 50 cc. In one particular embodiment, the volumetric scanner 81 is capable of acquiring at least 1,000,000 photons emitted from a volume of the ROI having a volume of no more than 200 cc;
    3. the volumetric scanner 81 is capable of acquiring an image of a resolution of at least 7×7×7 mm, such as at least 6×6×6 mm, 5×5×5 mm, 4×4×4 mm, 4×3×3 mm, or 3×3×3 mm, in at least 50% of the reconstructed volume, wherein the radiopharmaceutical as distributed within the ROI has a range of emission-intensities I (which is measured as emitted photons/unit time/volume), and wherein at least 50% of the voxels of the reconstructed three-dimensional emission-intensity image of the ROI have inaccuracies of less than 30% of range I, such as less than 25%, 20%, 15%, 10%, 5%, 2%, 1%, or 0.5% of range I. For example, the radiopharmaceutical may emit over a range from 0 photons/second/cc to 10A5 photons/second/cc, such that the range I is 105 photons/second/cc, and at least 50% of the voxels of the reconstructed three-dimensional intensity image of the ROI have inaccuracies of less than 15% of range I, i.e., less than 1.5×104 photons/second/cc. For some applications, the study produce a parametric image related to a physiological process occurring in each voxel. In one particular embodiment, the image has a resolution of at least 5×5×5 mm, and at least 50% of the voxels have inaccuracies of less than 15% of range I;
    4. the volumetric scanner 81 is capable of acquiring an image, which has a resolution of at least 7×7×7 mm, such as at least 6×6×6 mm, 5×5×5 mm, 4×4×4 mm, 4×3×3 mm, or 3×3×3 mm, in at least 50% of the reconstructed volume, wherein the radiopharmaceutical as distributed within the ROI has a range of emission-intensities I (which is measured as emitted photons/unit time/volume), and wherein at least 50% of the voxels of the reconstructed three-dimensional emission-intensity image of the ROI have inaccuracies of less than 30% of range I, such as less than 25%, 20%, 15%, 10%, 5%, 2%, 1%, or 0.5% of range I. For example, the radiopharmaceutical may emit over a range from 0 photons/second/cc to 105 photons/second/cc, such that the range I is 105 photons/second/cc, and at least 50% of the voxels of the reconstructed three-dimensional intensity image of the ROI have inaccuracies of less than 15% of range I, i.e., less than 1.5×10 photons/second/cc. For some applications, the study produces a parametric image related to a physiological process occurring in each voxel. In one particular embodiment, the image has a resolution of at least 5×5×5 mm, and at least 50% of the voxels have inaccuracies of less than 15% of range I;
    5. the volumetric scanner 81 is capable of acquiring an image, which has a resolution of at least 20×20×20 mm, such as at least 15×15×15 mm, 10×10×10 mm, 7×7×7 mm, 5×5×5 mm, 4×4×4 mm, 4×3×3 mm, or 3×3×3 mm, wherein values of parameters of a physiological process modeled by a parametric representation have a range of physiological parameter values I, and wherein at least 50% of the voxels of the reconstructed parametric three-dimensional image have inaccuracies less than 100% of range I5 such as less than 70%, 50%, 40%, 30%, 25%, 20%, 15%, 10%, 5%, 2%, 1%, or 0.5% of range I. For example, the physiological process may include blood flow, the values of the parameters of the physiological process may have a range from 0 to 100 cc/minute, such that the range I is 100 cc/minute, and at least 50% of the voxels of the reconstructed parametric three-dimensional image have inaccuracies less than 25% of range I, i.e., less than 25 cc/minute. In one particular embodiment, the image has a resolution of at least 5×5×5 mm, and at least 50% of the voxels have inaccuracies of less than 25% of range I; and/or
    6. the volumetric scanner 81 is capable of acquiring an image, which has a resolution of at least 7×7×7 mm, such as at least 6×6×6 mm, 5×5×5 mm, 4×4×4 mm, 4×3×3 mm, or 3×3×3 mm, in at least 50% of the reconstructed volume, wherein if the radiopharmaceutical is” distributed substantially uniformly within a portion of the ROI with an emission-intensity I+/−10% (which is defined as emitted photons/unit time/volume), and wherein at least 85% of the voxels of the reconstructed three-dimensional emission-intensity image of the portion of the ROI have inaccuracies of less than 30% of intensity I, such as less than 15%, 10%, 5%, 2%, 1%, 0.5%, 20%, or 25% of intensity I. For example, the radiopharmaceutical may be distributed within a volume with a uniform emission-intensity I of 10Λ5 photons/second/cc, and at least 85% of the voxels of the reconstructed three-dimensional intensity image of the volume have inaccuracies of less than 15% of intensity I, i.e., less than 1.5×104 photons/second/cc. For some applications, the same definition may apply to a study which produces a parametric image related to a physiological process occurring in each voxel. In one particular embodiment, the image has a resolution of at least 5×5×5 mm, and at least 50% of the voxels have inaccuracies of less than 15% of intensity I.

It is expected that during the life of a patent maturing from this application many relevant systems and methods will be developed and the scope of the term image, scanning, and directable detector is intended to include all such new technologies a priori.



As used herein the term “about” refers to ±10%.
The terms “comprises”, “comprising”, “includes”, “including”, “having” and their conjugates mean “including but not limited to”. This term encompasses the terms “consisting of” and “consisting essentially of”.
The phrase “consisting essentially of” means that the composition or method may include additional ingredients and/or steps, but only if the additional ingredients and/or steps do not materially alter the basic and novel characteristics of the claimed composition or method.
As used herein, the singular form “a”, “an” and “the” include plural references unless the context clearly dictates otherwise. For example, the term “a compound” or “at least one compound” may include a plurality of compounds, including mixtures thereof.
The word “exemplary” is used herein to mean “serving as an example, instance or illustration”. Any embodiment described as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments and/or to exclude the incorporation of features from other embodiments.
The word “optionally” is used herein to mean “is provided in some embodiments and not provided in other embodiments”. Any particular embodiment of the invention may include a plurality of “optional” features unless such features conflict.
Throughout this application, various embodiments of this invention may be presented in a range format. It should be understood that the description in range format is merely for convenience and brevity and should not be construed as an inflexible limitation on the scope of the invention. Accordingly, the description of a range should be considered to have specifically disclosed all the possible subranges as well as individual numerical values within that range. For example, description of a range such as from 1 to 6 should be considered to have specifically disclosed subranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6 etc., as well as individual numbers within that range, for example, 1, 2, 3, 4, 5, and 6. This applies regardless of the breadth of the range.
Whenever a numerical range is indicated herein, it is meant to include any cited numeral (fractional or integral) within the indicated range. The phrases “ranging/ranges between” a first indicate number and a second indicate number and “ranging/ranges from” a first indicate number “to” a second indicate number are used herein interchangeably and are meant to include the first and second indicated numbers and all the fractional and integral numerals therebetween.
It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable subcombination or as suitable in any other described embodiment of the invention. Certain features described in the context of various embodiments are not to be considered essential features of those embodiments, unless the embodiment is inoperative without those elements.
Although the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternatives, modifications and variations that fall within the spirit and broad scope of the appended claims.
All publications, patents and patent applications mentioned in this specification are herein incorporated in their entirety by reference into the specification, to the same extent as if each individual publication, patent or patent application was specifically and individually indicated to be incorporated herein by reference. In addition, citation or identification of any reference in this application shall not be construed as an admission that such reference is available as prior art to the present invention. To the extent that section headings are used, they should not be construed as necessarily limiting.

## Claims

1. A radiation detection apparatus for detecting radiation emanating from a body, comprising
a detector arm which comprises:
a) a radiation detector;
b) a collimator; and
c) a contact base positioned so as to be between said collimator and said body when said apparatus is used to detect radiation from said body,

said contact base being sufficiently distant from said collimator to enable at least part of said collimator to move to change direction of aim with respect to said body while said contact base is in stable contact with a surface of said body.

2. The apparatus of claim 1, wherein said collimator is swivel-mounted.

3. The apparatus of claim 1, wherein said contact base comprises a pad which comprises a gel that transmits ultrasound vibrations.

4. The apparatus of claim 1, wherein said contact base comprises a roller which rolls along said body surface when said contact base is in contact with said body surface while a distal portion of said arm is moved along said body surface.

5. The apparatus of claim 1, further comprising a plurality of detector arms.

6. The apparatus of claim 1, further comprising a gantry connecting to a proximal portion of said detector arm and a mechanical actuator operable to move a distal portion of said arm along said body surface.

7. The detector arm of claim 6, wherein said actuator is operable to rotate said detector while said contact base is in contact with said body surface.

8. A method of detecting radiation emanating from a body, comprising:
a) using an automated arm positioning system to position a distal portion of a detector arm so that said distal portion is in contact with a surface of said body and so that a radiation detector comprised in said distal portion is held at a distance from said body surface; and
b) using said automated arm positioning system to move said distal portion of said arm along said body surface while using said radiation detector to detect radiation from said body.

9. The method of claim 8, further comprising using an image processing module to estimate a contour of said body based on images from one or more image sensors, and controlling said movement of said arm to follow a pattern determined according to said estimated body contour.

10. The method of claim 8, further comprising using said automated arm positioning system to position and move a plurality of detector arms.

11. The method of claim 8, wherein said distal portion of a detector arm comprises at least one roller, and said moving of said arm comprises rolling a distal portion of said arm along said body surface.

12. The method of claim 8, wherein said radiation detector comprises a collimator mounted on a swivel, the method further comprising swiveling said collimator while said distal portion is in contact with said body surface, and using said swiveled collimator to detect radiation from a plurality of directions.

13. The method of claim 8, wherein said distal portion of said detector arm comprises a plurality of individually aimable radiation detectors.

14. The method of claim 13, wherein at least some of said plurality radiation detectors units are independently displaceable within said distal portion of said detector arm.

15. The method of claim 13, further comprising aiming said plurality of detector units so as to each detect radiation from a same body region.

16. The method of claim 8, wherein said detector arm is supported by a gantry.

17. The method of claim 16, further comprising moving said distal portion of said detector arm by at least one of:
a) rotating said gantry;
b) tilting said gantry; and
c) moving said gantry along said body surface.

18. The method of claim 8, further comprising rotating said detector arm while said detector arm is in contact with said body surface.

19. A method of volumetric scanning which comprises scanning a part of a patient's body using a detector arm which comprises a plurality of radiation detectors each mounted with a collimator which defines the solid angle from which radioactive emission events may be detected by its associated detector, comprising alternating between low-resolution and high-resolution scanning by alternating between use of at least one detector associated with a relatively low resolution collimator and use of at least one detector associated with a relatively high resolution collimator.

20. The method of claim 19, further comprising utilizing information gleaned during said use of said relatively low resolution collimator to calculate an aiming position for said relatively high resolution collimator.

21. The method of claim 20, further comprising moving said relatively high resolution collimator within said detector arm to said calculated aiming position.