Oxygen plasmas: a sharp chisel and handy trowel for nanofabrication

Although extremely chemically reactive, oxygen plasmas feature certain properties that make them attractive not only for material removal via etching and sputtering, but also for driving and sustaining nucleation and growth of various nanostructures in plasma bulk and on plasma-exposed surfaces. In this minireview, a number of representative examples is used to demonstrate key mechanisms and unique capabilities of oxygen plasmas and how these can be used in present-day nano-fabrication. In addition to modification and functionalisation processes typical for oxygen plasmas, their ability to catalyse the growth of complex nanoarchitectures is emphasized. Two types of technologies based on oxygen plasmas, namely surface treatment without a change in the size and shape of surface features, as well as direct growth of oxide structures, are used to better illustrate the capabilities of oxygen plasmas as a powerful process environment. Future applications and possible challenges for the use of oxygen plasmas in nanofabrication are discussed.

False positive F-18 fluorodeoxyglucose combined PET/CT scans from suture granuloma and chronic inflammation: report of two cases and review of literature

INTRODUCTION

F-18 fluorodeoxyglucose (FDG) combined positron emission tomography (PET)/ computed tomography (CT) imaging is often used in the surveillance of recurrent colorectal cancers after curative resections. We report 2 patients where FDG combined PET/CT imaging produced false positive results due to chronic inflammation and suture granuloma.

CLINICAL PICTURE

Case 1 is a patient with a curative anterior resection done 10 months ago. Serial surveillance carcinoembryonic antigen (CEA) showed a marginal elevation. A solitary "hot spot" on combined PET/CT imaging was seen at the level of the previously resected inferior mesenteric vein. Case 2 is a patient with a positive solitary lesion on combined PET/CT imaging 16 months after a curative right hemicolectomy for colorectal cancer. The serum CEA was within normal limits.

TREATMENT

Both patients had undergone exploratory laparotomy with complete resection of the solitary lesions.

OUTCOME

The histology of Case 1 was reported as a suture granuloma while the histology of Case 2 was reported as an inflammatory nodule related to the previous suture pedicle, both with no malignant tissues identified.

CONCLUSIONS

False positives on combined PET/CT imaging may result from inflammatory granulomas months after surgery.