CT radiation dose reduction with tin filter for localisation/characterisation level image quality in PET-CT: a phantom study.

Background: The tin filter has allowed radiation dose reduction in some standalone diagnostic computed tomography (CT) applications. Yet, 'low-dose' CT scans are commonly used in positron emission tomography (PET)-CT for lesion localisation/characterisation (L/C), with higher noise tolerated. Thus, dose reductions permissible with the tin filter at this image quality level may differ.

Ultra-low-dose CT for attenuation correction: dose savings and effect on PET quantification for protocols with and without tin filter.

Background: Ultra-low-dose (ULD) computed tomography (CT) scans should be used when CT is performed only for attenuation correction (AC) of positron emission tomography (PET) data. A tin filter can be used in addition to the standard aluminium bowtie filter to reduce CT radiation dose to patients. The aim was to determine how low CT doses can be, when utilised for PET AC, with and without the tin filter, whilst providing adequate PET quantification.

Lesion detection in 18F-sodium fluoride bone imaging: a comparison of attenuation-corrected versus nonattenuation-corrected PET reconstructions from modern PET-CT systems.

Objectives: An earlier study demonstrated comparable lesion detection between attenuation-corrected (AC) and nonattenuation-corrected (NAC) 18F-sodium fluoride (NaF) PET images, which is relevant for computed tomography (CT) radiation dose-saving. However, this finding may not be applicable to newer systems. The aim was to compare lesion detection between AC and NAC NaF PET images on modern PET-CT systems.

Validation of CARE kV automated tube voltage selection for PET-CT: PET quantification and CT radiation dose reduction in phantoms.

Background: Applied tube voltage (kilovolts, kV) and tube current (milliampere seconds, mAs) affect CT radiation dose and image quality and should be optimised for the individual patient. CARE kV determines the kV and mAs providing the lowest dose to the patient, whilst maintaining user-defined reference image quality. Given that kV changes affect CT values which are used to obtain attenuation maps, the aim was to evaluate the effect of kV changes on PET quantification and CT radiation dose using phantoms.

Estimation of CARE Dose 4D quality reference mAs conversion factors for child to adult reference patient in child protocols on Siemens Symbia SPECT-CT systems.

Objectives: CARE Dose 4D modulates mAs through several mechanisms according to patient size and shape, whilst maintaining user-defined reference image quality on Siemens Symbia single-photon emission computed tomography (SPECT)-computed tomography (CT) systems. A 20 kg child reference was used in child protocols prior to software version VB10 and a 75 kg adult thereafter. Quality reference mAs conversion factors are estimated for delivering equivalent mAs to children between two comparable SPECT-CT systems using adult and child references for topogram-based patient-size-related dose level adaptations.