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prostate diseases, including PCa [43,44] . A detailed review of these studies, reflecting the contradictions within
accumulated data, was given in our earlier publication .
[44]

In present study it was supposed by us that apart from Zn the levels of some other TE in EPF have to reflect
a difference between possible functional suppression of hyperplastic prostate and functional disintegration
of cancerous prostate. Thus, this work had four aims. The first one was to present the design of the method
and apparatus for micro analysis of bromine (Br), iron (Fe), rubidium (Rb), strontium (Sr), and Zn in the EPF
samples using energy dispersive X-ray fluorescence (EDXRF) with radionuclide source Cd. The second
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aim was to assess the Br, Fe, Rb, Sr, and Zn concentration in the EPF samples received from patients with
BPH and PCa. The third aim was to evaluate the quality of obtained results and to compare obtained results
with published data. The last aim was to compare the concentration of Br, Fe, Rb, Sr, and Zn in EPF samples
of hyperplastic and cancerous prostate gland.

METHODS
Specimens of EPF were obtained from 52 patients with BPH (mean age 63 ± 6 years, range 52-75 years) and
from 24 patients with PCa (mean age 65 ± 10 years, range 47-77 years) by qualified urologists in the Urological
Department of the Medical Radiological Research Centre using standard rectal massage procedure. In all
cases the diagnosis of BPH or PCa has been confirmed by clinical examination, including morphological
results obtained during studies of biopsy and resected materials. Patients with BPH combined with chronic
prostatitis or prostatic stones were excluded from the study. Subjects were asked to abstain from sexual
intercourse for 3 days preceding the procedure. Specimens of EPF were obtained in sterile containers which
were appropriately labeled. Twice 20 μL of fluid were taken by micropipette from every specimen for trace
element analysis, while the rest of the fluid was used for cytological and bacteriological investigations to
exclude prostatitis. The chosen 20 μL of the EPF was dropped on 11.3 mm diameter disk made of thin, ash-
free filter papers fixed on the Scotch tape pieces and dried in an exsiccator at room temperature. Then the
dried sample was covered with 4 μm Dacron film and centrally pulled onto a Plexiglas cylindrical frame.

To determine concentration of the elements by comparison with a known standard, aliquots of solutions
of commercial, chemically pure compounds were used for a device calibration . The standard samples for
[45]
calibration were prepared in the same way as the samples of prostate fluid. Because there were no available
liquid Certified Reference Material (CRM) ten sub-samples of the powdery CRM IAEA H-4 (animal muscle)
were analyzed to estimate the precision and accuracy of results. Every CRM sub-sample weighing about 3 mg
was applied to the piece of Scotch tape serving as an adhesive fixing backing. An acrylic stencil made in the
form of a thin-walled cylinder with 11.3 mm inner diameter was used to apply the sub-sample to the Scotch
tape. The polished-end acrylic pestle which is a constituent of the stencil set was used for uniform distribution
of the sub-sample within the Scorch surface restricted by stencil inner diameter. When the sub-sample was
slightly pressed to the Scotch adhesive sample, the stencil was removed. Then the sub-sample was covered with
4 μm Dacron film. Before the sample was applied, pieces of Scotch tape and Dacron film were weighed using
analytical balance. Those were again weighed together with the sample inside to determine the sub-sample
mass precisely.

The facility for radionuclide-induced energy dispersive X-ray fluorescence included an annular Cd source
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with an activity of 2.56 GBq, Si(Li) detector with electric cooler and portable multi-channel analyzer
combined with a PC. Its resolution was 270 eV at the 6.4 keV line. The facility functioned as follows. Photons
with the 22.1 keV energy from Cd source are sent to the surface of a specimen analyzed, where they
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excite the characteristic fluorescence radiation, inducing the K a X-rays of trace elements. The fluorescence
radiation got to the detector through a 10 mm diameter collimator to be recorded.