AMC4

In this study hyperthermia treatment planning is used to investigate whether the target temperature during hyperthermia treatment can be increased using the 3D AMC-8 instead of the 2D AMC-4 system (AMC: Academic Medical Center).

The heating ability of the AMC-4 and AMC-8 system was analysed for five patients with cervix uteri carcinoma. Dielectric and thermal models were generated, based on a hyperthermia planning computerised tomography (CT), at a resolution of 2.5 × 2.5 × 5.0 mm(3). Calculation of the electric fields with the finite-difference time-domain method was followed by SAR- and temperature-based optimisation. The ability to correct for axial shifts of the patient by phase/amplitude steering was investigated for both systems. Finally, it was investigated whether adjusting the ring-to-ring distance of the AMC-8 system can be used for further optimisation.

An average increase in T(90) of ∼0.5°C (0.2°-0.8°C) was found for the AMC-8 system compared to the AMC-4 system. The gain in T(50) and T(10) was also 0.5°C on average. The additional power required to achieve this gain was 36% to 71% of the power required for the AMC-4 system. The AMC-8 system has the capability of correcting changes in axial position (-8 cm, +8 cm), contrary to the AMC-4 system. For both systems the axial position should be known within 1-2 cm.

Hyperthermia treatment with the AMC-8 system can lead to a clinically relevant increase of the target temperature compared to treatment with the AMC-4 system. The AMC-8 system provides large freedom in the axial positioning of the patient.

ABSTRACT. The nucleotide sequence of the 16S rRNA gene, part of the 23S rRNA gene and the spacer DNA region was determined for Giardia duodenalis, obtained from humans in The Netherlands (AMC‐4) and Washington State (CM). These rDNA sequences differ from other G. duodenalis isolates (Portland‐1 and BRIS/83/HEPU/106) both of which have virtually identical rDNA sequences. The most characteristic feature was found close to the 5’end of the 16S rRNA. The Portland‐1 ‐ Bris/83/HEPU/106 type has GCG in position 22–24, while AMC‐4 and CM have AUC in this position. These two sequences, present in an otherwise conserved region of the 16S rRNA, are “signature” sequences, which divide Giardia isolates into two different groups.