China
Africa
Explore chapters and articles related to this topic
Small Animal Imaging and Therapy
Published in George C. Kagadis, Nancy L. Ford, Dimitrios N. Karnabatidis, George K. Loudos, Handbook of Small Animal Imaging, 2018
The major strength of PET imaging is that radionuclides such as carbon-11, nitrogen-13, or oxygen-15 can be incorporated in the molecule with minimal interference to the function of pharmaceuticals. This allows for developing radiolabeled probes, which are chemically almost identical to the parent compounds. This strategy has been successfully employed to develop PET tracers, which can pass the blood–brain barrier and can be used for imaging brain function (Judenhofer et al. 2008; Mariani et al. 2010).
Fate of Radiometabolites
Published in Lelio G. Colombetti, Principles of Radiopharmacology, 1979
Radioactive gases are eliminated by the lungs with a rate following the breathing. Radiometabolites are scarcely eliminated with the expired air, unless they are formed of CO2. It has been shown, in animals, that 14CO2 and 14CH4 have been detected after injection of a molecule containing an amino (carbon 14) methyl group: −NH14CH3. The elimination of 11CO2 is observed in certain circumstances when patients are given carbon 11 radiotracers with such radicals. The use of nitrogen 13 amino acids may lead to the expiration of ammoniac gas 13NH3.
Molecular imaging in management of colorectal metastases by the interventional oncologist
Published in International Journal of Hyperthermia, 2022
Stephen Hunt, Alireza Zandifar, Abass Alavi
Real-time PET-CT can also be utilized for more accurate targeting during tumor ablation, however several considerations must be made. First, ablation does not get rid of the FDG tracer activity, and intraprocedural post-thermal ablation imaging can continue to demonstrate tracer activity in the tumor [35]. This persistence, however, can be utilized to examine post-ablation margins by combining intraprocedural FDG-PET-CT imaging with post-ablation contrast-enhanced CT or a PET perfusion agent such as nitrogen-13 ammonia PET [36]. An FDG split-dose technique has been described which uses a small initial dose of FDG for tumor localization and targeting, and a larger post-ablation dose for immediate assessment of residual viable tumor (Figure 2) [37]. This allows for additional targeting of the lesion, and post ablation FDG activity has been demonstrated to correlate with biopsy-positive tumor margins and recurrence [38]. Most recently, a split-dose technique has been described which combines an initial pre-ablation FDG-PET dose for tumor localization followed by a second FDG-PET dose used as a perfusion agent for post-ablation margin assessment [39]. Of course, any benefits to the use of intraprocedural molecular imaging must be balanced against the cost in procedural resources, time, personnel, and additional radiation dose to the treatment team [24].
Contemporary evidence on colorectal liver metastases ablation: toward a paradigm shift in locoregional treatment
Published in International Journal of Hyperthermia, 2022
Yuan-Mao Lin, Reto Bale, Kristy K. Brock, Bruno C. Odisio
Despite the widely recognized need for sufficient minimal ablation margins on a three-dimensional plane, fundamental limitations still exist on how to properly assess such ablation margins intra- and post-procedurally. This is due to a series of factors: the tumor is obscured by the ablation zone, precluding its mapping within the ablation zone; the complex changes in the patient’s position, post-ablation tissue retraction and inflammation, and imaging resolution [80,81]. Ongoing efforts such as the use of deformable imaging registration methods aim to provide accurate modeling of ablation zone assessment (Figure 5) [80,82–86]. Furthermore, some intraoperative techniques are used to facilitate the targeting of tumors and ablation assessment. A split-dose technique for FDG PET/CT guidance has been developed, which allows prompt tumor targeting and immediate postablation assessment [87–89]. The main concept of this technique is that a smaller first dose of FDG before the ablation will be significantly decayed by the time the second larger dose is administered, allowing for the detection of FDG activity within any residual viable tumor. Another technique using intraprocedural nitrogen 13 ammonia perfusion PET has been developed to assess the ablation margins [86]. For ultrasound guidance, using intravenous contrast can improve tumor detection sensitivity [85,90]. A post-ablation contrast-enhanced ultrasound can provide an immediate evaluation of residual tumors and guidance to supplementary ablation [90].
Gastrointestinal vaso-occlusive crisis in sickle cell disease
Published in Baylor University Medical Center Proceedings, 2022
Garima Gautam, Robert Harmon, Raymond Foley
A 34-year-old woman with glucose-6-phosphatase deficiency and SCD presented with abdominal pain, nausea, vomiting, and dyspnea. She had a history of prior sickle cell crises and received transfusions; however, this episode had proven to be refractory to her home pain regimen. The temperature was 97.2°F; blood pressure, 70/44 mm Hg; heart rate, 104 beats/min; and oxygen saturation, 91% on a 3 L nasal cannula. Physical examination showed a diaphoretic patient in distress, with tachycardia, a systolic murmur, tachypnea, no respiratory wheezes or crackles, and a benign abdominal exam. Her potassium was 6.8 mmol/L; serum bicarbonate, 14 mmol/L; blood urea nitrogen, 13 mg/dL; creatinine, 1.6 mg/dL; lactic acid, 14.5 mmol/L; and troponin, 0.06 mg/dL. Her white blood cell count was 12,000 μ/L; hemoglobin, 6.4 g/dL; hematocrit, 19.6%; mean corpuscular volume, 101.4 fL; platelets, 200,000/μ; and reticulocyte count, 29.2%. Hemoglobin electrophoresis revealed a hemoglobin A of 29.8%, hemoglobin S of 60.3%, hemoglobin F of 7.2%, and hemoglobin A2 of 2.7%. Arterial blood gas disclosed a pH of 7.013, partial pressure of oxygen of 253.6 mm Hg, and partial pressure of carbon dioxide of 56.8 mm Hg. The total bilirubin was 2.3 mg/dL; direct bilirubin, 0.6 mg/dL; alkaline phosphatase, 59 U/L; aspartate transaminase, 60 U/L; and alanine transaminase, 43 U/L. Her blood cultures were negative, and a methicillin-resistant Staphylococcus aureus polymerase chain reaction test was positive. The patient was admitted to the medical intensive care unit for further management.