Disclosed herein are methods and devices for the acquisition of positron emission (or PET) data in the presence of ionizing radiation that causes afterglow of PET detectors. In one variation, the method comprises adjusting a coincidence trigger threshold of the PET detectors during a therapy session. In one variation, the method comprises adjusting a gain factor used in positron emission data acquisition (e.g., a gain factor used to multiply and/or shift the output(s) of a PET detector(s)) during a therapy session. In some variations, a method for acquiring positron emission data during a radiation therapy session comprises suspending communication between the PET detectors and a signal processor of a controller for a predetermined period of time after a radiation pulse has been emitted by the linac.

Disclosed herein are methods and devices for the acquisition of positron emission (or PET) data in the presence of ionizing radiation that causes afterglow of PET detectors. In one variation, the method comprises adjusting a coincidence trigger threshold of the PET detectors during a therapy session. In one variation, the method comprises adjusting a gain factor used in positron emission data acquisition (e.g., a gain factor used to multiply and/or shift the output(s) of a PET detector(s)) during a therapy session. In some variations, a method for acquiring positron emission data during a radiation therapy session comprises suspending communication between the PET detectors and a signal processor of a controller for a predetermined period of time after a radiation pulse has been emitted by the linac.

Disclosed herein are methods and devices for the acquisition of positron emission (or PET) data in the presence of ionizing radiation that causes afterglow of PET detectors. In one variation, the method comprises adjusting a coincidence trigger threshold of the PET detectors during a therapy session. In one variation, the method comprises adjusting a gain factor used in positron emission data acquisition (e.g., a gain factor used to multiply and/or shift the output(s) of a PET detector(s)) during a therapy session. In some variations, a method for acquiring positron emission data during a radiation therapy session comprises suspending communication between the PET detectors and a signal processor of a controller for a predetermined period of time after a radiation pulse has been emitted by the linac.

Timing calibration of a positron emission tomography (PET) imaging device (2) uses a radioactive source (20) comprising a positron-emitting radioisotope having a decay path including emission of two oppositely directed 511 keV gamma rays and a cascade gamma ray at a cascade gamma ray energy. A timestamped radiation detection event data set acquired from the radioactive source by the PET imaging device is processed using energy window filtering (32) and time window filtering (36) to generate a coincidence data set (40, 42, 44) including event pairs (40) each consisting of two coincident 511 keV events and cascade event pairs (42) or triplets (44) each consisting of at least one coincident 511 keV event and a coincident cascade event at the cascade gamma ray energy. A timing calibration (12) is generated using the coincidence data set. The timing calibration comprises offset times for PET detectors of the PET imaging device.

Timing calibration of a positron emission tomography (PET) imaging device (2) uses a radioactive source (20) comprising a positron-emitting radioisotope having a decay path including emission of two oppositely directed 511 keV gamma rays and a cascade gamma ray at a cascade gamma ray energy. A timestamped radiation detection event data set acquired from the radioactive source by the PET imaging device is processed using energy window filtering (32) and time window filtering (36) to generate a coincidence data set (40, 42, 44) including event pairs (40) each consisting of two coincident 511 keV events and cascade event pairs (42) or triplets (44) each consisting of at least one coincident 511 keV event and a coincident cascade event at the cascade gamma ray energy. A timing calibration (12) is generated using the coincidence data set. The timing calibration comprises offset times for PET detectors of the PET imaging device.

An electromagnetic radiation detector of an embodiment includes a first scintillation detector that detects incidence of electromagnetic radiation and includes a first scintillator that outputs photons in response to the incidence of electromagnetic radiation; a second scintillation detector that detects scattered electromagnetic radiation exiting from the first scintillation detector, the scattered electromagnetic radiation that occurs inside the first scintillation detector due to Compton scattering of the electromagnetic radiation; and a multi-channel analyzer that performs multi-channel analysis of a result of the detection by the first scintillation detector, the result being other than results of the detection, timing of which is considered to coincide with timing of the detection by the second scintillation detector. The second scintillation detector includes a second scintillator formed by turning scintillator powder into paste and solidifying the paste into a thick film through compression and drying.

An electromagnetic radiation detector of an embodiment includes a first scintillation detector that detects incidence of electromagnetic radiation and includes a first scintillator that outputs photons in response to the incidence of electromagnetic radiation; a second scintillation detector that detects scattered electromagnetic radiation exiting from the first scintillation detector, the scattered electromagnetic radiation that occurs inside the first scintillation detector due to Compton scattering of the electromagnetic radiation; and a multi-channel analyzer that performs multi-channel analysis of a result of the detection by the first scintillation detector, the result being other than results of the detection, timing of which is considered to coincide with timing of the detection by the second scintillation detector. The second scintillation detector includes a second scintillator formed by turning scintillator powder into paste and solidifying the paste into a thick film through compression and drying.

Timing calibration of a positron emission tomography (PET) imaging device (2) uses a radioactive source (20) comprising a positron-emitting radioisotope having a decay path including emission of two oppositely directed 511 keV gamma rays and a cascade gamma ray at a cascade gamma ray energy. A timestamped radiation detection event data set acquired from the radioactive source by the PET imaging device is processed using energy window filtering (32) and time window filtering (36) to generate a coincidence data set (40, 42, 44) including event pairs (40) each consisting of two coincident 511 keV events and cascade event pairs (42) or triplets (44) each consisting of at least one coincident 511 keV event and a coincident cascade event at the cascade gamma ray energy. A timing calibration (12) is generated using the coincidence data set. The timing calibration comprises offset times for PET detectors of the PET imaging device.

A data processing apparatus according to an embodiment includes acquisition circuitry and specification circuitry. The acquisition circuitry is configured to acquire a detector signal containing a first component that is based on Cherenkov light and a second component that is based on scintillation light. The specification circuitry is configured to specify timing information about generation of the detector signal by curve fitting to the first component.

A data processing apparatus according to an embodiment includes acquisition circuitry and specification circuitry. The acquisition circuitry is configured to acquire a detector signal containing a first component that is based on Cherenkov light and a second component that is based on scintillation light. The specification circuitry is configured to specify timing information about generation of the detector signal by curve fitting to the first component.