Transmission line source assembly for spect cameras

A nuclear camera system comprising:

• a stationary gantry portion;
• a rotary gantry portion rotatably mounted to the stationary gantry portion for circumferential movement around an examination region;
• at least one nuclear camera detector head mounted to the rotary gantry portion for rotation therewith, the nuclear camera detector head having a radiation sensitive face facing toward the examination region;
• a transmission radiation source assembly mounted to the rotary gantry portion across the examination region from the nuclear radiation detector head, the transmission radiation source assembly including:
• a transmission radiation source,
• a shutter having a shutter cylinder rotatably mounted surrounding the transmission radiation source for selectively allowing and preventing radiation from the transmission radiation source to be transmitted from the radiation source across the examination region to the nuclear camera detector head, the shutter cylinder including a lead segment for blocking the emission of transmission radiation in a closed position, an open segment for passing radiation freely in an open position, and a partially radiation transmissive portion for passing filtered radiation in a calibration position, and
• a collimator for collimating radiation emerging from the transmission radiation source.

A nuclear camera system comprising:

• a stationary gantry portion;
• a rotary gantry portion rotatably mounted to the stationary gantry portion for circumferential movement around an examination region;
• at least one nuclear camera detector head mounted to the rotary gantry portion for rotation therewith, the nuclear camera detector head having a radiation sensitive face facing toward the examination region;
• a transmission radiation source assembly mounted to the rotary gantry portion across the examination region from the nuclear radiation detector head, the transmission radiation source assembly including:
• a transmission radiation source,
• a shutter for selectively allowing and preventing radiation from the transmission radiation source to be transmitted from the radiation source across the examination region to the nuclear camera detector head, and
• a collimator for collimating radiation emerging from the transmission radiation source, the collimator including a pair of side walls and a plurality of septa extending therebetween, the septa being disposed parallel to a selected radiation path, such that radiation travelling along the selected radiation path pass therebetween and radiation which deviates from the selected path is blocked by the septa, the septa being constructed of a radiation absorbing material from the group consisting of tin, antimony, zirconium, niobium, molybdenum, germanium, yttrium, cerium, gadolinium, terbium, dysprosium, holmium, erbium, ruthenium, rhodium, palladium, silver, cadmium, indium, tellurium, cesium, barium, and alloys thereof.

A nuclear camera system comprising:

• a stationary gantry portion;
• a rotary gantry portion rotatably mounted to the stationary gantry portion for circumferential movement around an examination region;
• at least one nuclear camera detector head mounted to the rotary gantry portion for rotation therewith, the nuclear camera detector head having a radiation sensitive face facing toward the examination region;
• a transmission radiation source assembly mounted to the rotary gantry portion across the examination region from the nuclear radiation detector head, the transmission radiation source assembly including:
• a transmission radiation source,
• a shutter for selectively allowing and preventing radiation from the transmission radiation source to be transmitted from the radiation source across the examination region to the nuclear camera detector head,
• a collimator for collimating radiation emerging from the transmission radiation source, and
• a filter connected across a downstream side of the collimator away from the transmission radiation source, the filter including:
• an inner layer which passes a substantial portion of radiation from the transmission radiation source and which emits radiation of a lower energy than the transmission radiation source;
• and
• an outer layer constructed of a material which blocks the passage of radiation of the lower energy emitted by the inner layer.

The radiation source and collimator assembly for a SPECT camera system, the radiation source and collimator assembly including:

• a transmission radiation source;
• a shutter for selectively allowing and preventing radiation from the transmission radiation source to be transmitted from the transmission radiation source;
• a collimator for collimating radiation emerging from the transmission radiation source;
• a connecting means for selectively connecting and releasing the radiation source and collimator assembly to an associated SPECT camera system;
• a safety interlock means for locking the shutter in a closed position, the safety interlock means being released by interconnection of the radiation source and collimator assembly with the associated SPECT camera system.

A radiation source and collimator assembly for a SPECT camera system, the radiation source and collimator assembly including:

• a transmission radiation source including an elongated, tube containing radioactive material and a sheath of radiation absorbing material around the tube, the radiation absorptive sheath having a radiation passing slot
• a shutter including a cylinder rotatably mounted around the radiation absorbing sheath for selectively allowing and preventing radiation from the transmission radiation source to be transmitted from the transmission radiation source;
• a collimator for collimating radiation emerging from the transmission radiation source;
• a connector for selectively connecting and releasing the radiation source and collimator assembly to an associated SPECT camera system.

A radiation source and collimator assembly for a SPECT camera system, the radiation source and collimator assembly including:

• a transmission radiation source;
• a shutter for selectively allowing and preventing radiation from the transmission radiation source to be transmitted from the transmission radiation source;
• and
• a collimator for collimating radiation emerging from the transmission radiation source to direct the radiation along a selected trajectory, the collimator including a pair of side walls and a plurality of septa extending therebetween, the septa extending parallel to the selected trajectory such that radiation travelling along the selected trajectory passes therebetween and radiation travelling at other than the selected trajectory is absorbed by the septa causing the septa to give off radiation, the septa being constructed from a metal with an atomic number between 30 and 70 such that the radiation given off by the septa is lower in energy than the radiation from the transmission radiation source;
• and
• a connector which connects the radiation source and collimator assembly to an associated SPECT camera system.

A radiation source and collimator assembly for a SPECT camera system, the radiation source and collimator assembly including:

• a transmission radiation source;
• a shutter for selectively allowing and preventing radiation from the transmission radiation source to be transmitted from the transmission radiation source;
• and
• a collimator for collimating radiation emerging from the transmission radiation source;
• a filter connected across and covering a downstream side of the collimator away from the transmission radiation source to protect the collimator and to filter radiation from the radiation source, the filter including:
• an inner layer which passes a substantial portion of radiation from the transmission radiation source and which emits radiation of a lower energy than the transmission radiation source;
• and
• an outer layer constructed of a material which blocks the passage of radiation of the lower energy emitted by the inner layer;
• a connector for connecting the radiation source and collimator assembly to the associated SPECT camera system.

A method of diagnostic imaging comprising:

• injecting a subject with a radiopharmaceutical;
• receiving radiation from the radiopharmaceutical with a radiation detector head;
• transmitting radiation from a radiation source through a radiation filter and through the subject to the detector head, the transmission radiation source including a radioisotope whose radioactivity decays
• reconstructing an image representation from the radiopharmaceutical radiation and correcting the image representation in accordance with the transmission radiation;
• replacing the filter with a series of filters which attenuate the transmitted radiation less as the transmission radiation source decays, such that radiation passing through the filter is held at a substantially constant level as the transmission radiation source radioisotope decays.

A method of diagnostic imaging comprising:

• injecting a subject with a radiopharmaceutical;
• receiving radiation from the radiopharmaceutical with a radiation detector head;
• transmitting radiation from a transmission radiation source that gives off higher energy gamma rays through a collimator which includes septa and side walls;
• absorbing some of the higher energy gamma rays with the septa and side walls, the septa and side walls giving off lower energy gamma rays in response to the absorbed higher energy gamma rays;
• attenuating the lower energy gamma rays with a filter;
• transmitting transmission radiation that has passed through the filter through the subject to the detector head;
• reconstructing an image representation from the radiopharmaceutical radiation and correcting the image representation in accordance with the transmission radiation.

A method of diagnostic imaging comprising:

• injecting a subject with a radiopharmaceutical;
• receiving radiation from the radiopharmaceutical with a radiation detector head;
• transmitting radiation from a transmission radiation source through a collimator which includes septa and side walls, at least a portion of the septa and side walls being constructed of lead which emits 88 keV radiation in response to being irradiated;
• with a first layer of the filter, converting the 88 keV radiation from the collimator to a lower energy radiation;
• with a second layer of the filter, attenuating the lower energy radiation;
• transmitting radiation from the filter through the subject to the detector head;
• reconstructing an image representation from the radiopharmaceutical radiation and correcting the image representation in accordance with the radiation from the transmission radiation source.

A method of diagnostic imaging comprising:

• injecting a subject with a radiopharmaceutical;
• receiving radiation from the radiopharmaceutical with a radiation detector head that is mounted on a SPECT camera gantry;
• transmitting radiation from a transmission radiation source which is detachably mounted to the SPECT camera gantry across the subject form the detector head;
• locking a shutter which opens and closes the transmission radiation source in a closed position whenever the radiation source assembly is detached from the camera gantry;
• opening the shutter and passing radiation from the transmission radiation source through a radiation filter and through the subject to the detector head;
• reconstructing an image representation from the radioisotope radiation and correcting the image representation in accordance with the transmission radiation.