A real-time prostate cancer detection technique using needle insertion force and patient-specific criteria during percutaneous intervention

In this article, the authors present a novel real-time cancer detection technique by using needle insertion forces in conjunction with patient-specific criteria during percutaneous interventions. Needle insertion experiments and pathological analysis were performed for developing a computer-aided detection (CAD) model. Backward stepwise regression method was performed to identify the statistically significant patient-specific factors. A baseline force model was then developed using these significant factors. The threshold force model that estimated the lower bound of the cancerous tissue forces was formulated by adding an adjustable classifier to the baseline force model. Tradeoff between sensitivity and specificity was obtained by varying the threshold value of the classifier, from which the receiver-operating characteristic (ROC) curve was generated. Sequential quadratic programming was used to optimize the CAD model by maximizing the area under the ROC curve (AUC) using a set of model-training patient data. When the CAD model was evaluated using an independent set of model-validation patient data, an AUC of 0.90 was achieved. The feasibility of cancer detection in real time during percutaneous interventions was established.

A real-time prostate cancer detection technique using needle insertion force and patient-specific criteria during percutaneous intervention

In this article, the authors present a novel real-time cancer detection technique by using needle insertion forces in conjunction with patient-specific criteria during percutaneous interventions. Needle insertion experiments and pathological analysis were performed for developing a computer-aided detection (CAD) model. Backward stepwise regression method was performed to identify the statistically significant patient-specific factors. A baseline force model was then developed using these significant factors. The threshold force model that estimated the lower bound of the cancerous tissue forces was formulated by adding an adjustable classifier to the baseline force model. Trade-off between sensitivity and specificity was obtained by varying the threshold value of the classifier, from which the receiver-operating characteristic (ROC) curve was generated. Sequential quadratic programming was used to optimize the CAD model by maximizing the area under the ROC curve (AUC) using a set of model-training patient data. When the CAD model was evaluated using an independent set of model-validation patient data, an AUC of 0.90 was achieved. The feasibility of cancer detection in real time during percutaneous interventions was established.

Targeting of breast cancer with non-oncology drugs – possible novel therapeutic option for triple-negative breast cancer

Abstract #2119

Introduction: Triple-negative breast cancer (TNBC) is defined by lack of ER, and PR expression and normal HER2 expression. It is characterized by aggressive biological presentation and unfavorable outcome. It is associated with frequent lack of response to current chemotherapy agents. Recently, 392 drugged genes that serve as targets for 1557 both oncologic and non-oncologic drugs were identified from the pharmacologic database DrugBank (Lauss et al. Pharmacogenomics 2007). In this study, we compared expression levels of these known drug targets between TNBC and receptor-positive cancers. Methods: Gene expression profiles were obtained from fine needle biopsies of newly diagnosed early stage breast cancer before any therapy (n=133, MDACC dataset). Differential expression of these genes was validated in a second independent data set (n=286, Rotterdam dataset) and in a panel of cell lines (n=19). In order to assess the functional relevance of known drug targets overexpressed in TNBC we performed in vitro experiments. Cell lines were treated with various concentrations of selected drugs alone or in combination with paclitaxel. Results: We mapped 675 U133A probe sets representing 347 unique drug targets to the Affymetrix U133A Genechip. 44 drug targets were overexpressed in TNBC compared to non-TNBC in the MDACC dataset. Thirty-three of these (75%) were also overexpressed among TNBC compared to non-TNBC in the Rotterdam dataset. Glutathione-S-transferase pi (GSTpi, target of clomipramine) was the most highly and consistently overexpressed target in human TNBC and in estrogen- and HER2-receptor-negative breast cancer cell lines. The GSTpi overexpressing (and triple negative) human mammary cell line HBL-100 showed dose-dependent inhibition of growth after 144 hrs of incubation with clomipramine, whereas growth of the GSTpi-low expressing (non-triple negative) breast cancer cell lines MCF-7 and SKBR3 was not inhibited by this drug. Treatment with clomipramine did not alter sensitivity to paclitaxel in either cell line in vitro. Conclusion: Gene expression analysis indicates that targets for several known drugs are over expressed in TNBC relative to other types of breast cancers. We hypothesize that some of these drugs may influence the behavior of TNBC and may represent future therapeutic options. Further experiments are needed to fully explore the functional implications of these findings; however, our preliminary results suggest that inhibition of GSTpi with clomipramine leads to inhibition of cell growth of TNBC cell lines in vitro.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 2119.

A high-voltage pulse transformer with a modular ferrite core

A high ratio (winding ratio of 1:80) pulse transformer with a modular ferrite core was developed for a repetitive resonant charging system. The magnetic core is constructed from 68 small blocks of ferrites, glued together by epoxy resin. This allows a high degree of freedom in choosing core shape and size. Critical issues related to this modular design are the size tolerance of the individual ferrite blocks, the unavoidable air gap between the blocks, and the saturation of the core. To evaluate the swing of the flux density inside the core during the charging process, an equivalent circuit model was introduced. It was found that when a transformer is used in a resonant charging circuit, the minimal required volume of the magnetic material to keep the core unsaturated depends on the coupling coefficient of the transformer and is independent of the number of turns of the primary winding. Along the flux path, 17 small air gaps are present due to the inevitable joints between the ferrite blocks. The total air gap distance is about 0.67 mm. The primary and secondary windings have 16 turns and 1280 turns, respectively, and the actually obtained ratio is about 1:75.4. A coupling coefficient of 99.6% was obtained. Experimental results are in good agreement with the model, and the modular ferrite core works well. Using this transformer, the high-voltage capacitors can be charged up to more than 70 kV from a low-voltage capacitor with an initial charging voltage of about 965 V. With 26.9 J energy transfer, the increased flux density inside the core was about 0.23 T, and the core remains unsaturated. The energy transfer efficiency from the primary to the secondary was around 92%.

The role of contrast-enhanced ultrasound in planning treatment protocols for hepatocellular carcinoma before radiofrequency ablation

AIM

To evaluate the clinical value of contrast-enhanced ultrasound (CEUS) for patients with hepatocellular carcinoma (HCC) in identifying the tumour number, ablation range and feeding vessels before ultrasound-guided radiofrequency ablation (RFA), and to compare the efficacy of RFA after CEUS with the efficacy of RFA after non-enhanced ultrasonography (US) without contrast medium administration.

MATERIALS AND METHODS

From 2002 to 2005, 81 patients with 110 HCCs underwent CEUS with SonoVue before RFA treatment (group A). Eighty six patients with 112 HCCs who underwent US without contrast enhancement before RFA served as the control group (group B). The average diameters of the lesions in group A and group B were 3.6+/-1.1cm and 3.5+/-1.1cm, respectively. There were no significant differences in clinical data between the two groups. Regular follow-up after treatment was performed using contrast-enhanced computed tomography (CECT). After treatment, complete necrosis was defined as the absence of viable tissue in treated tumours at the 1-year follow-up CECT.

RESULTS

Using CEUS an additional seven small lesions (< or =2.0 cm) were found compared with those found using CECT and conventional US. CEUS showed that 56.4% of lesions (62/110 tumours) were larger in size and 49.1% (54/110 tumours) became more irregular in shape during the arterial phase than on conventional US. Feeding vessels were detected using CEUS in 52 (91.2%) of 57 lesions that were larger than 3.5 cm. The follow-up period was at least 1 year for each case. The complete tumour necrosis rate in group A was significantly higher than that in group B (92.2% versus 83.0%; p=0.036).

CONCLUSION

CEUS can be used to more accurately define the size and contour of lesions, and to detect additional small or satellite lesions and the feeding vessel of HCC tumours. CEUS provided important information for designing the ablation protocol, and might improve the efficacy of RFA.