Annals of nuclear medicine
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Comparative Study
Evaluation of the risk of radiation exposure from new 18FDG PET/CT plans versus conventional X-ray plans in patients with pediatric cancers.
Unnecessary radiological examination should be avoided, particularly for children, who are more vulnerable to radiation than adults. Replacement of X-ray examination with 18F-fluoro-2-deoxy-D-glucose (18FDG) positron emission tomography/computed tomography (PET/CT) is a potential option for reduction of radiation exposure, and thus improvement in the quality of life (QOL) of patients. Therefore, this study aimed to evaluate new plans integrating 18FDG PET/CT versus current conventional imaging (CI) plans for patients with pediatric cancers. The effects of radiation exposure from the two kinds of plans were compared using shortening of the average life expectancy as an index, and the related findings and effects of radiation exposure are discussed. ⋯ New 18FDG PET/CT plans may relieve the patient's physical burden and contribute to improvement of the patient's QOL. These plans may also reduce medical costs because the number of examinations to be performed is reduced. Although deterministic effects are not observed in the CI plan, careful attention should be paid to other potential effects. Because the effective dose resulting from this plan is over 100 mSv, at which stochastic effects are known to occur, radiation-induced cancers may be expected.
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The deep-inspiration breath-hold PET/CT (DIBH PET/CT) technique improves the limitations of diagnosing a lesion located in an area influenced by respiratory motion that results in spatial misregistrations caused by respiration between PET and CT. However, its reproducibility with regard to calculating the maximal standardized uptake value (SUV(max)) and metabolic volume (MV) in DIBH PET/CT has not been elucidated. ⋯ The DIBH technique improves the inaccurate quantification of both SUV(max) and MV. Although the CV value of SUV(max) with DIBH technique is better in thoracic lesions compared with that in abdominal lesions, the reproducibility was acceptable.
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In positron emission tomography/computed tomography (PET/CT) examinations, the standardized uptake value (SUV) is a commonly used index to evaluate the activity of cancer. The precision of SUV is directly affected by the local statistical noise in PET images because SUV is calculated based on the counts on PET image data. The purpose of this study was to estimate the local statistical noise in the PET image caused by attenuation of annihilation photons inside the body. ⋯ Our algorithm favorably estimated the local statistical noise in PET image data using CT image data, regardless of object size, although the consideration was limited for phantoms with homogeneous interiors.
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The deep inspiration breath-hold (DIBH) technique for positron emission tomography/computed tomography (PET/CT) is under investigation for its contribution to the accurate diagnosis of pulmonary lesions. "Step and shoot" or multi-bed-position image acquisition is necessary to improve the accuracy of whole-lung evaluation. The purpose of this study was to describe the method and preliminary results of evaluating pulmonary lesions using multi-bed-position deep inspiration breath-hold (MDIBH) PET/CT. ⋯ The MDIBH-PET/CT can provide better-aligned fused images, featuring superior image quality, in both PET and CT images. The PET images showed low BG, non-blurring and high TBRs, and the CT images provided diagnostic capability of detecting small pulmonary lesions with negligible radiation exposure.
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The transition of microglia from the normal resting state to the activated state is associated with an increased expression of peripheral benzodiazepine receptors (PBR). The extent of PBR expression is dependent on the level of microglial activation. A PBR ligand, [(11)C]PK11195, has been used for imaging of the activation of microglia in vivo. We evaluated whether [(11)C]PK11195 PET can indicate differences of microglial activation between no treatment and lipopolysaccharide (LPS) treatment in a rat artificial injury model of brain inflammation. ⋯ The results suggest that intensity of PBR signals in [(11)C]PK11195 PET may be related to the level of microglial activation rather than the number in activated microglia at least in an artificial brain injury model.