title: Evaluation of two Compton camera models for scintimammography

authors: Uche, Chibueze Zimuzo

subjects: Compton camera

abstract: We study the performance of a Si/LaBr3:Ce Compton camera model for scintimammography, and compare it with a Si/NaI(Tl) model of similar geometry. The GEANT4 simulation toolkit was used to study the behaviour of the cameras at 511 keV. Certain simulation steps, such as the modelling of radionuclide decay times, scintillation photon transport and interactions with photomultipliers, as well as detector dead time corrections were included to make the modelling of the cameras more realistic than previous studies. The Si/LaBr3:Ce Compton camera shows superior efficiency of 2.0×10⁻³ and resolution of 5.3 mm over the Si/NaI(Tl) Compton camera model which has the efficiency of 1.6×10⁻³ and resolution of 6.9 mm at a source-to-scatterer distance of interest, 2.5 cm. A similar result sequence is obtained for two breast tumours of 5 mm diameter embedded in the medial region of an average-size breast phantom of thickness 5 cm. Notably, the signal-to-noise ratios (SNR) obtained for the Si/LaBr3:Ce camera are 9.7 and 3.4 for tumour/background radiation uptakes of 10:1 and 6:1, whereas 6.8 and 2.4 were obtained for the Si/NaI(Tl) camera model for the same tumour/background radiation uptakes respectively. It is therefore envisioned that with lower cost, LaBr3:Ce could replace NaI(Tl) as the Compton camera absorber.

text: Evaluation of two Compton camera models for scintimammography We study the performance of a Si/LaBr3:Ce Compton camera model for scintimammography, and compare it with a Si/NaI(Tl) model of similar geometry. The GEANT4 simulation toolkit was used to study the behaviour of the cameras at 511 keV. Certain simulation steps, such as the modelling of radionuclide decay times, scintillation photon transport and interactions with photomultipliers, as well as detector dead time corrections were included to make the modelling of the cameras more realistic than previous studies. The Si/LaBr3:Ce Compton camera shows superior efficiency of 2.0×10⁻³ and resolution of 5.3 mm over the Si/NaI(Tl) Compton camera model which has the efficiency of 1.6×10⁻³ and resolution of 6.9 mm at a source-to-scatterer distance of interest, 2.5 cm. A similar result sequence is obtained for two breast tumours of 5 mm diameter embedded in the medial region of an average-size breast phantom of thickness 5 cm. Notably, the signal-to-noise ratios (SNR) obtained for the Si/LaBr3:Ce camera are 9.7 and 3.4 for tumour/background radiation uptakes of 10:1 and 6:1, whereas 6.8 and 2.4 were obtained for the Si/NaI(Tl) camera model for the same tumour/background radiation uptakes respectively. It is therefore envisioned that with lower cost, LaBr3:Ce could replace NaI(Tl) as the Compton camera absorber.

year: 2011

title: I’d like to complain about this software…

authors: Nichols, David M.

subjects: computer science

abstract: Software is often frustrating. You need only walk past a group of users to hear exclamations of annoyance as the users’ expectations and the software interface clash head on.

text: I’d like to complain about this software… Software is often frustrating. You need only walk past a group of users to hear exclamations of annoyance as the users’ expectations and the software interface clash head on.

year: 2003

title: Reimagining community resilience through a Te Ao Maori worldview

authors: Boston, Megan

abstract: Efforts to improve community resilience have seen universal efforts to grow capabilities in disaster management for the built environment. Although comprehensive frameworks exist, the perspective used to derive these frameworks fails to address marginalised communities' vulnerabilities, including Indigenous Māori people. Colonization and socio-economic deprivation on Māori mean community response frameworks fail to reflect their values and specific needs when preparing and responding to natural disasters. The nature of Māori culture and values presents an opportunity to reimagine the scope of community resilience for an inclusive framework. The Māori history has resilient practices weaved into the very fabric of their culture, which knowledge has survived through the oral transmission of waiata, whakataukī, whakairo, and pūrakau. The practice of community resilience amongst ancient Māori was not consigned to singular events but instead is a holistic perspective to the manner of living. Sourcing and qualifying this information from people aligned and immersed in nature is the knowledge required to improve the frameworks to respond to natural disasters while expanding the literature on community resilience. A comprehensive analysis of traditional Māori resilience is conducted by evaluating a variety of Mātauranga Māori that relate to the resilient nature of Māori. This information is compared to modern Māori perceptions of community resilience using a derived earthquake scenario for the local Iwi Ngati Toa, located in the city of Porirua within the Wellington region. This information will enable a comprehensive definition of community resilience and improve disaster response frameworks to be more inclusive, safe, sustainable, and resilient.

text: Reimagining community resilience through a Te Ao Maori worldview Efforts to improve community resilience have seen universal efforts to grow capabilities in disaster management for the built environment. Although comprehensive frameworks exist, the perspective used to derive these frameworks fails to address marginalised communities' vulnerabilities, including Indigenous Māori people. Colonization and socio-economic deprivation on Māori mean community response frameworks fail to reflect their values and specific needs when preparing and responding to natural disasters. The nature of Māori culture and values presents an opportunity to reimagine the scope of community resilience for an inclusive framework. The Māori history has resilient practices weaved into the very fabric of their culture, which knowledge has survived through the oral transmission of waiata, whakataukī, whakairo, and pūrakau. The practice of community resilience amongst ancient Māori was not consigned to singular events but instead is a holistic perspective to the manner of living. Sourcing and qualifying this information from people aligned and immersed in nature is the knowledge required to improve the frameworks to respond to natural disasters while expanding the literature on community resilience. A comprehensive analysis of traditional Māori resilience is conducted by evaluating a variety of Mātauranga Māori that relate to the resilient nature of Māori. This information is compared to modern Māori perceptions of community resilience using a derived earthquake scenario for the local Iwi Ngati Toa, located in the city of Porirua within the Wellington region. This information will enable a comprehensive definition of community resilience and improve disaster response frameworks to be more inclusive, safe, sustainable, and resilient.

year: 2023