ABSTRACT
OBJECTIVE: We aimed to estimate the effective dose of 4D-Perfusion-CT protocols of the lung, liver, and pelvis for the assessment of tumor vascularity. MATERIALS AND METHODS: An Alderson-Rando phantom equipped with thermoluminescent dosimeters was used to determine the effective dose values of 4D-Perfusion-CT. Phantom measurements were performed on a 128-slice single-source scanner in adaptive 4D-spiral-mode with bidirectional table movement and a total scan range of 69 mm over a time period of nearly 120 seconds (26 scans). Perfusion measurements were simulated for the lung, liver, and pelvis under the following conditions: lung (80 kV, 60 mAs), liver (80 kV/80 mAs and 80 kV/120 mAs), pelvis (100 kV/80 mAs and 100 kV/120 mAs). RESULTS: Depending on gender, the evaluated body region and scan protocol, an effective whole-body dose between 2.9-12.2 mSv, was determined. The radiation exposure administered to gender-specific organs like the female breast tissue (lung perfusion) or to the ovaries (pelvic perfusion) led to an increase in the female specific dose by 86% and 100% in perfusion scans of the lung and the pelvis, respectively. CONCLUSION: Due to a significant radiation dose of 4D-perfusion-CT protocols, the responsible use of this new promising technique is mandatory. Gender- and organ-specific differences should be considered for indication and planning of tumor perfusion scans.
Subject(s)
Female , Humans , Male , Four-Dimensional Computed Tomography , Neoplasms/blood supply , Phantoms, Imaging , Radiation DosageABSTRACT
OBJECTIVE: To test whether proton magnetic resonance spectroscopy (1H-MRS) reveals changes in the lipid content of the gastrocnemius muscle (GM) and soleus muscle (SOL) of a patient with unilateral isolated hypertrophy of the right GM. MATERIALS AND METHODS: 1H-MRS was performed on a 1.5 Tesla (T) whole-body unit. Muscular lipids inside SOL and GM were assessed in both calves of the patient by a STEAM (stimulated echo acquisition mode) localization sequence. Results were compared to a control group of four healthy volunteers. RESULTS: Total amount of muscular lipids in the hypertrophic GM of the patient was clearly increased compared to the controls (38.7 versus 21.8+/-3.5 a.u.) while intramyocellular lipids of the adjacent SOL were lower compared to the contralateral healthy leg. CONCLUSION: Muscular lipids are substrates for metabolism and can be assessed non-invasively by 1H-MRS. 1H-MRS is considered to be a helpful tool in clinical assessment of muscle metabolism in cases with muscular hypo- or hypertrophy.