Stereotactically navigated percutaneous microwave ablation (MWA) compared to conventional MWA: a matched pair analysis.

PURPOSE: To compare CT-navigated stereotactic microwave ablation (SMWA) to non-navigated conventional MWA (CMWA) for percutaneous ablation of liver malignancies. METHODS: A matched pair analysis of 36 patients who underwent MWA of primary or secondary liver malignancies (10 hepatocellular carcinoma and 8 metastases) was conducted. A total of 18 patients undergoing SMWA were included in this prospective study. Patients were matched in terms of tumor size, liver segment and entity to retrospective CMWA procedures. The endpoints were procedure time, accuracy of needle placement, technical success rate, complication rate and dose-length product (DLP). RESULTS: The procedure durations were 23.9 min (SD 3.7) for CMWA and 21.8 min (SD 16.3) for SMWA (p = 0.22). The procedural accuracy for SMWA and CMWA was identical for both groups (3.7 mm). The total DLP was significantly lower for SMWA than for CMWA (2115 mGy cm (SD 276) vs. 3109 mGy cm (SD 1137), respectively; p < 0.01). Complete ablation without residual tumor was observed in 94% (17 of 18) of SMWA and in 83% (15 of 18) of CMWA patients (p = 0.31). No complications occurred. CONCLUSIONS: SMWA is highly accurate and reduces the radiation dose without increasing the procedure time.

Evaluation of a robotic system for irreversible electroporation (IRE) of malignant liver tumors: initial results.

OBJECTIVE: Comparison of conventional CT-guided manual irreversible electroporation (IRE) of malignant liver tumors and a robot-assisted approach regarding procedural accuracy, intervention time, dose, complications, and treatment success. METHODS: A retrospective single-center analysis of 40 cases of irreversible electroporation of malignant liver tumors in 35 patients (6 females, 29 males, average age 60.3 years). Nineteen of these ablation procedures were performed manually and 21 with robotic assistance. A follow-up (ultrasound, CT, and MRI) was performed after 6 weeks in all patients. RESULTS: The time from the planning CT scan to the start of the ablation as well as the dose-length product were significantly lower under robotic assistance (63.5 vs. 87.4 min, [Formula: see text]; 2132 vs. 4714 mGy cm, [Formula: see text]). The procedural accuracy, measured as the deviation of the IRE probes with respect to a defined reference probe, was significantly higher using robotic guidance (2.2 vs. 3.1 mm, [Formula: see text]). There were no complications. There was one incomplete ablation in the manual group. CONCLUSION: Robotic assistance for IRE of liver tumors allows for faster procedure times with higher accuracy while reducing radiation dose as compared to the manual placement of IRE probes.

Percutaneous irreversible electroporation (IRE) of prostate cancer: Contrast-enhanced ultrasound (CEUS) findings during follow up.

PURPOSE: Irreversible electroporation (IRE) is a focal non-thermal ablation technique that can be used to treat prostate cancer (Pca). The objective was to document the evolution of the volume of the prostate gland and the ablation zone after IRE of Pca. MATERIAL AND METHODS: A retrospective analysis of the image findings of CEUS 1 day, 6 weeks, 3 months and 6 months after IRE of 25 patients was conducted. The prostate gland volumes and the size of the ablation zones were documented. Changes in volume and size over time were calculated. RESULTS: There was a significant volume reduction of the prostate gland in the first 3 months after ablation. The mean percentage change after 6 weeks was 34.3% with another decrease of 35.0% after 3 months. Volume did not change between month 3 and 6. Size of ablation zone measured in short- and long-axis significantly diminished until 6 months after ablation. CONCLUSION: CEUS showed a significant involution of the prostate gland during the first 3 months and a significant decrease of the ablation zone during the first 6 months after IRE of prostate cancer.

Interpretation of analysis of variance models using principal component analysis to assess the effect of a maternal anticancer treatment on the mineralization of rat bones.

The goal of the present study is to assess the effects of anticancer treatment with cyclophosphamide and cytarabine during pregnancy on the mineralization of mandible bones in 7-, 14- and 28-day-old rats. Each bone sample was described by its X-ray fluorescence spectrum characterizing the mineral composition. The data collected are multivariate in nature and their structure is difficult to visualize and interpret directly. Therefore, methods like analysis of variance-principal component analysis (ANOVA-PCA) and ANOVA-simultaneous component analysis (ASCA), which are suitable for the analysis of highly correlated spectral data and are able to incorporate information about the underlined experimental design, are greatly valued. In this study, the ASCA methodology adapted for unbalanced data was used to investigate the impact of the anticancer drug treatment during pregnancy on the mineralization of the mandible bones of newborn rats and to examine any changes in the mineralization of the bones over time. The results showed that treatment with cyclophosphamide and cytarabine during pregnancy induces a decrease in the K and Zn levels in the mandible bones of newborns. This suppresses the development of mandible bones in rats in the early stages (up to 14 days) of formation. An interesting observation was that the levels of essential minerals like K, Mg, Na and Ca vary considerably in the different regions of the mandible bones.

Role of endogenous zinc in bones of newborn rats.

Concentration of abundant elements e.g. calcium as well as of elements present in trace amount e.g. zinc in mandibles of 7, 14 an 28 day old newborn rats were determined by X-ray fluorescence analysis. The measurements were carried out by using a measurement system containing X-ray tube ECLIPSE-III and X-ray and gamma ray detector XR-100T-CdTe (Amptek Inc.). Concentration of calcium and zinc depended on the region of interest on the rat's mandible due to mineralization degree conditioned by its function. Increasing age produced a remarkable increase in Ca content in contrast to Zn content in the bone tissue obtained from 7, 14 and 28 day old newborn rats. The calculated Zn/Ca concentration ratio was the biggest for 7 day old newborns and successively decreased with age indicating the important role of zinc at the beginning of bone ontogenesis.

Influence of magnesium glutamate on stability of penicillin G aqueous solution.

Differential scanning microcalorimetry (DSC) has been used to determine the influence of magnesium glutamate on the stability of penicillin G in aqueous solution. The degradation of penicillin is accompanied by an evolution of heat and has been observed as an irreversible, scan rate dependent, broad exothermic transition. The increase of the transition temperature Tm and enthalpy change DeltaH with increasing magnesium glutamate concentration indicates the increase of penicillin G stability. The kinetic parameters describing the penicillin decomposition process, obtained for a reaction following a first-order course, suggest maximum penicillin G stability if about two molecules of salt per one penicillin molecule are present in solution.