Ru(II) diimine complexes having phosphonic acid substituents adsorb to TiO 2 modified ITO electrodes and exhibit electrogenerated chemiluminescence when potentiostated at positive voltages in the presence of oxalate in buffered aqueous solutions.

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Most nuclear medicine clinicians use only visual assessment when interpreting regional cerebral blood flow (rCBF) from single-photon emission computed tomography (SPECT) images in clinical practice. The aims of this study were to develop a new, easy to use, automated method for quantification of rCBF-SPECT and to create normal values by using the method on a normal population. We developed a 3-dimensional method based on a brain-shaped model and the active-shape algorithm. The method defines the surface shape of the brain and then projects the maximum counts 0–1·5 cm deep for designated surface points. These surface projection values are divided into cortical regions representing the different lobes and presented relative to the whole cortex, cerebellum or cerebellar maximum. 99mTc-hexa methyl propylene amine oxime (HMPAO) SPECT was performed on 30 healthy volunteers with a mean age of 74 years (range 64–98). The ability of the active-shape algorithm to define the shape of the brain was satisfactory when visually scrutinized. The results of the quantification show rCBF values in the frontal, temporal and parietal lobes of 87–88% using cerebellum as the reference. There were no significant differences in normal rCBF values between male and female subjects and only a weak relation between rCBF and age. In conclusion, our new automated method was able to quantify rCBF-SPECT images and create normal values in ranges as expected. Further studies are needed to assess the clinical value of this method and the normal values.

Objective-To investigate patients with cystic enhancing lesions on CT and to determine whether thallium-201 ( 201 Tl) SPECT adds to further preoperative information in diVerential diagnosis between gliomas and abscesses. Methods-Twenty one patients with cystic ring enhancing CT findings were studied and uptake indices were compared with CT enhancement volumes, histopathology, and survival times. Results-Fourteen high grade gliomas, three low grade gliomas, and four abscesses were found. Uptake was higher in the highly malignant glioma group (median thallium index (TI)=2.1), than in the low grade glioma group (median TI=1.4) or among the abscesses (median TI=1.6). Overlapping indices were found between high and low malignant cystic gliomas as well as between either one of the glioma groups and the infectious lesions, and there were no significant diVerences between groups. There was a level at the value 2, where TI>2 correlated with tumour diagnosis. One low grade tumour had an extremely high index and a very high enhancement volume. Indices correlated significantly with CT enhancement volumes (P=0.005). There was no significant correlation between Tl indices and patient survival times among the high grade gliomas. One patient with a highly malignant tumour but low Tl uptake <2, had a survival> five years. Conclusions-It is concluded that high 201Tl uptake in enhancing cystic lesions is an indicator of highly malignant glioma. However, the diVerentiation between the high malignant gliomas and abscesses or low malignant gliomas by 201 TL SPECT is only partial with an overlap between these groups.

The aim of this study was to establish if repeated quantitative 201Tl SPET scanning during follow-up of astrocytoma therapy can provide information that is relevant for clinical management. Sixteen consecutive patients, with histopathologically verified highly malignant astrocytoma, were followed during PCV chemotherapy. Imaging with 201Tl SPET and CT was performed repeatedly over 8-16 weeks until treatment discontinuation, with a maximum follow-up of 74 weeks. Tumour uptake volume (TUV), a measure of metabolically active tumour tissue, was calculated from the SPET images. The reliability of early identification of treatment failure, defined as > 25% tumour volume increase, following one course (week 8) and three courses (week 24) of chemotherapy, was calculated for the two imaging methods. 201Tl SPET positive patients (> 25% tumour volume increase) were compared with 201Tl SPET negative patients in terms of time to treatment discontinuation (TTD) and survival time (ST). The patients were followed with a total of 59 SPET examinations, and treatment was continued for a median 27 weeks (range 16-78 weeks). The comparative reliability of SPET and CT showed the highest sensitivity and accuracy for SPET in the early identification of astrocytoma treatment failure at the week 24 assessment. Patients with positive 201Tl SPET after three courses of chemotherapy had a significantly reduced TTD (P = 0.040) but not significantly reduced ST. Of the ten patients who received concomitant radiation and chemotherapy, five had a small (0-10 ml) TUV at the week 24 assessment. Patients with a TUV > 10 ml at this assessment had a shorter TTD (P = 0.016) and a reduced ST (P = 0.024) compared to patients with a TUV < 10 ml. In conclusion, the assessment of progressive disease by quantitative 201Tl SPET appears to provide information on treatment response, earlier and with a higher reliability than CT. Repeated 201Tl SPET scanning during follow-up of astrocytoma treatment is an alternative tool for the early identification of treatment failure.