Search

Scintigraphy with 99mTc labelled heat-denatured erythrocyte (DRBC) allows non invasive diagnosis of heterotopic splenic tissue implantation (splenosis) following splenic trauma or surgery. Single-photon emission computed tomography (SPECT) combined with computed tomography (CT) improves diagnostic accuracy of planar imaging through a more precise localization of functional findings. We report about two cases of splenosis occurring many years after splenectomy. 99MTc-DCRBC scintigraphy was used for differential diagnosis of metasttic disease in one case and to assess an incidental finding at bone scan in the second one. SPECT/CT increased specificity of planar imaging, expecially revealing combined (thoracic and abdominal) splenosis.

Background: Chemokine receptor-4 (CXCR4) is involved in tumor growth and progression in several types of human cancer. Recently, [68Ga]-DOTA-Pentixafor has been assessed as an excellent imaging probe targeting CXCR4-expression using positron emission tomography (PET). Here we report on the entire production cycle of [68Ga]-DOTA-Pentixafor, including quality control development and process validation., Methods: Synthesis of [68Ga]-DOTA-Pentixafor was validated via three independent and consecutive production runs using an automated synthesis system. All validation runs must pass the pre-set quality control (QC) limits. Validation was performed for established QC tests to ensure that methods were reproducible and reliable in routine use. Germanium-68 breakthrough was determined for each sample. Production yield was calculated for each synthesis to assess the performance and efficiency of the radiolabeling process. The quality of the final product was determined by ITLC and HPLC methods after each synthesis., Results: The average ITLC-measured radiochemical purity was above 98.5% and HPLC-measured radiochemical purity was 99.86%, 99,83% and 100% in the three validation runs. Germanium breakthrough was 4.8*10-5%, 4.9*10-5% and 4.7*10-5% of total activity, far below the recommended level of 0.001%. Residual ethanol resulted 5.22%, 5.58% and 5.32%V/V; spot of HEPES impurity was not more intense than spot of reference solution (200µg/V). Endotoxin level resulted <17.5EU/ml. pH of the final product was 7 in all samples., Conclusion: [68Ga]-DOTA-Pentixafor fit requirements of the pre-set quality parameters of purity, efficacy and safety in the batches considered for this study  and fulfilled all the acceptance criteria for injectable radiopharmaceutical products. The results demonstrated a batch-to-batch reproducibility providing high radiochemical purity.

Background and Aim: Selective imaging of the splenic tissue is obtained with heat-damaged, or heat-denatured, red blood cells (RBCs) of the patient labeled with 99mTc in a variety of clinical scenarios. Aim of the study was to validate the process used for labelling heat-damaged red blood cells "totally in vitro", after blood sample collection, before re-inject labeled RBCs to the patient. Moreover, we assessed efficacy of the staff training programme in order to guarantee repeatibility and method standardization in the clinical routine., Methods: The validation process of the labeling procedure was performed in three different patients during three consecutive days. After collection of a blood sample using a heparinized syringe, we isolated erythrocytes from other blood components by centrifugation and washing steps. Then, we added the stannous pyrophosphate (PYP) to the erythrocytes pellet, after  pH control. The 'pretinning' of RBCs was necessary to reduce Tc-99m once pertechnetate was entered them. After the labeling reaction with 130 MBq of 99mTc-pertechnetate, the erythrocytes were denatured in a water bath at a temperature of 49°-50°C, for 10 min. Radioactivity of blood aliquotes was measured with a dose calibrator and labelling efficiency (LE%) was determined. The labelling purity was measured using a gamma counter  and calculated using the formula: counts of pellet/counts of pellet+(counts of surnatant)*100.Training program was evaluated using a Learning Questionnaire (LQ). with a grading score from 6 ("") to 1 ("nothing") for each operator (n=3)., Results: We didn't observed the presence of macroaggregates during the entire process, until the final sample. The labelling efficiency resulted at very high values in the three consecutive measured aliquotes (mean value 73.67%) as well as the labelling purity (>95.22%). In our instituion, we use splenic imaging with labelled heat-damaged RBCs to detect ectopic spleen, splenosis, extramedullary hematopoiesis. We performed 3 procedures with  heat-damaged labeled RBCs with a  mean labelling efficiency 73.67%.Training and learning programmes were scored by key objective areas with a mean value of 5., Conclusions: Our in vitro labeling process of heat-damaged RBCs is simple and safe, providing a useful technique  easy to implement in clinical routine for splenic imaging Learning outcome of the training programme was scored as effective by all the operators with evidence of high-efficiency-reproducible procedure mantained over time.

Background and Aim: Labeled leukocytes with 99mTc-HMPAO are routinely used for infection imaging. Although cell labeling with 99mTc-HMPAO represents an imaging probe to detect infection sites, the diagnostic efficiency of the probe is largely influenced by cell manipulation, multidisciplinary interventions (i.e., biologist, technicians) and available technology (i.e., SPECT, SPECT/CT). The aim of the study was to assess in vitro and in vivo accuracy of a comprehensive approach for quality assessment (QA) of all steps of the procedure., Methods: Radiochemical purity (RCP), pH, labeling efficiency (LE) were measured in 320 procedures. White Cell Viability Factor (WVF) was determined in consecutive blood samples. Images (490 studies) were scored using a 5-point scale. Training program was evaluated using a Learning Questionnaire and a score system., Results: Pre/post-labelling WVF was 0.99% (max value 1%) in all blood samples. LE (mean value 72%) and RCP (>80% until 55 minutes) yielded considerably high values. The vast majority of images were scored as diagnostic by three independent observer (90% with score ≥4)., Conclusions: This method appears highly reproducible and easy to use in clinical routine for leukocyte labeling, especially when standardized training and total QA system are implemented.