CT apparatus for imaging cranial anatomies
Inventors
Laukkanen, Tapio • Tohka, Sami • Seppala, Lauri
Assignees
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Publication Number
US-9955928-B2
Publication Date
2018-05-01
Expiration Date
Abstract
The invention relates to a medical computed tomography imaging apparatus which is especially designed to enable cranial imaging. The structure of the apparatus includes a gantry (2) comprising imaging means (21, 22) and a positioning support (8) which positioning support (8) is arranged to position the patient's cranium for exposure such that, when exposed, the cranium is scanned by a radiation beam substantially parallel with a plane formed by the facial area of the cranium and substantially only in an area on the facial side of the cranium.
Core Innovation
The disclosed invention relates to CT, including cone-beam, cranial imaging apparatus and methods using a ring shaped structure supporting a source of radiation and a detector. The ring shaped structure defines an examination opening or cranium receiving passage, and the patient is positioned so the face enters the opening from one side and extends toward an opposed side during exposure.
A two-dimensional radiation beam is driven around the ring shaped structure for at least 180 degrees while scanning only a face side of the cranium, and only a volume located within an area on the face side of the cranium is imaged. Radiation that penetrates the face side of the cranium is detected by a detector moving on the opposite side of the ring shaped structure, and the radiation is implemented with a two-dimensional expanding radiation beam limited by a collimator.
The apparatus includes cranial positioning support within the examination opening, including a forehead support and a trough-shaped support structure including jaw support, to align the face plane relative to the scan plane. By aligning the face plane and constraining the imaging to the face side, the approach keeps radiation-sensitive tissue outside the irradiated volume, with the thyroid gland specifically described as excluded from the imaged volume.
The disclosed configuration includes features that facilitate positioning, such as a partially cut outer cover and a non-circular examination opening, and a field of view constraint where an imaging area field of view volume is smaller than the cranial volume, with an example constraint stated as less than about 4 dm^3.
Claims Coverage
The partial content includes three independent method claims. The claims center on a ring shaped radiation structure with an opening for patient facial-side positioning, a two-dimensional radiation beam driven around at least 180 degrees, and detection by a detector located on the opposite side, with additional orientation and regional imaging limitations in specific claims.
Ring shaped radiation structure with face-side opening
Providing a ring shaped structure supporting a source of radiation and positioning the patient's face through an opening in the ring shaped structure such that the face enters an opening in the ring shaped structure from one side and extends toward an opposed side of the opening during an exposure of radiation.
Two-dimensional radiation beam driven around at least 180 degrees scanning face-side cranium
Implementing the exposure of radiation using a two-dimensional radiation beam which is driven around the ring shaped structure for at least 180 degrees and scans a face side of the cranium such that a volume being imaged by the exposure of radiation is located only within an area on the face side of the cranium.
Opposite-side detector for penetrated radiation
Detecting the radiation having penetrated the face side of the cranium by a detector moving on the opposite side of the ring shaped structure.
Parallel scan relative to ring circumference plane
Radiating parallel to a plane formed by 3 points on the circumference of the ring shaped structure and scanning only from a face side of the cranium.
Ring shaped structure defining cranium receiving passage in vertical plane
Providing a ring shaped structure residing in a vertical plane, the ring shaped structure further defining a cranium receiving passage wherein the patient's face enters one side of the passage and extends toward an opposed side of the passage, the passage having a longitudinal axis.
Forehead support perpendicular surface and partial cranium penetration
Positioning the cranium for imaging against a forehead support disposed within the cranium receiving passage such that the cranium penetrates only partially into the passage, the forehead support defining a cranium receiving surface perpendicular to the longitudinal axis.
Imaging only region abutting forehead support via at least 180 degrees rotation
Imaging only a region of the cranium abutting the forehead support by at least 180 degrees rotation of the radiation beam.
Across the independent claims, the core inventive elements are the ring shaped radiation support with a face-side opening or passage, exposure using a two-dimensional radiation beam driven around the ring for at least 180 degrees with scanning limited to the face side, and detection of penetrated radiation by a detector moving on the opposite side.
Stated Advantages
Keeps radiation-sensitive tissue outside the irradiated volume, with the thyroid gland specifically described as excluded from the imaged volume.
Documented Applications
No documented applications found
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