Adaptive 18fluoro-2-deoxyglucose positron emission tomography/computed tomography-based target volume delineation in radiotherapy planning of head and neck cancer.

AIMS: This study investigated an adaptive threshold-based method to delineate the target volume using (18)fluoro-2-deoxyglucose ((18)FDG) positron emission tomography/computed tomography (PET/CT) before and during a course of radical radiotherapy or chemoradiotherapy in locally advanced squamous cell carcinoma of the head and neck. MATERIALS AND METHODS: Ten patients were enrolled between March 2006 and May 2008. (18)FDG PET/CT scans were carried out 72h before the start of radiotherapy and then at three time points during radiotherapy (8-18, 36-50 and 66Gy). Functional volumes were delineated using an adaptive iterative algorithm weighted according to the mean standard uptake value (SUV(mean)) within the region of interest. The background (18)FDG uptake, maximum standard uptake value (SUV(max)) and SUV(mean) within the volumes were assessed. RESULTS: There was no significant reduction in the primary target volumes defined by the adaptive threshold during radiotherapy. However, the SUV(max) significantly reduced within the primary (P=0.003-0.011) and lymph node (P<0.0001) target volume at 36-50 and 36-66Gy compared with 0Gy. The SUV(mean) was negatively correlated to radiation dose (P<0.0001-0.014). The ratio between the background uptake of (18)FDG and the SUV(mean) significantly reduced for both the lymph node target volume at 36-50Gy and the primary volume at 66Gy. The lack of significant correlation between the defined volume and radiation dose was because the SUV(mean) within the region of interest used to define the edge of the volume was equal to or less than the background (18)FDG uptake and the software was unable to effectively differentiate between tumour and background uptake. CONCLUSIONS: The adaptive threshold method may be of benefit when used to define the target volume before the start of radiotherapy. This method was not beneficial during radiotherapy because the software is not sensitive enough to distinguish tumour from background and define a volume. (18)FDG PET/CT-guided volumes delineated by automatic adaptive thresholding methods should only be used for dose escalation with the pretreatment imaging.

Incidental fleurodeoxyglucose uptake in the prostate.

This commentary confirms the rarity of prostatic cancer associated with incidental prostatic fleurodeoxyglucose (FDG) uptake. The study adds to the literature by showing that even if a prostate lesion is FDG avid it is unlikely to be due to cancer. The commentary considers the management of incidental prostate FDG uptake on the basis of the available evidence.

Dramatic response to platinum in a patient with cancer with a germline BRCA2 mutation.

We present a case of dramatic response of poor prognosis cancer in a lady with a germline mutation in the BRCA2 gene who was exposed to platinum containing chemotherapy. She is cancer-free 10 years' later. Such cases provide clinical scenarios for the basis of trials of platinum-like agents in individuals with BRCA mutations who develop cancer.

Percutaneous absorption and disposition of Tinopal EMS.

A cotton-substantive, anionic, fluorescent whitening agent manufactured by several suppliers under various trade names e.g. Tinopal EMS, has been synthesized in radioactive form. Intubation of detergent or aqueous solution into rats resulted in little absorption from the intestinal tract as evidenced by low radioactivity in the urine and tissues. Most of the dose was excreted rapidly in the faeces. After parenteral administration to rats, the radioactivity was rapidly excreted in the faeces with small amounts remaining in tissues and organs. There was slight evidence of retention of radioactivity in the kidneys. Very small amounts of Tinopal EMS in detergent were absorbed through rat skin, but only when concentrations greater than those normally used by the consumer, together with occlusion of the skin were employed. Small amounts were absorbed throught skin when applied in ethanol. It is concluded that the possibility of systemic toxic effects in man as a result of percutaneous absorption is remote.