Universiteit van die Oranje-Vrystaat - SAMJ Archive Browser

620 SAMJ VOL. 80 7.DES 1991
Kerngeneeskundi e beelde is gerestoureer deur die
Wienerfilter ( W(!) ) in die Fourier-gebied toe te pas, waar
met MOF die modulasie-oordrags-funksie wat die ruimtelike
oplosvermoE vervat en RSV die ruis-tot-sein-verhouding. Die
eerste term kanselleer die effek van die ruimtelike
oplosvermoE en doen dus randverskerping. By hoe
frekwensies word die RSV baie groot en dus neig die hele
tweede term na nul. Die filter onderdruk dus ook hoe-
frekwensie ruis.
Die resultate toon dat die Wienerfilter beter beeldrestourasie
gee as die Hanningfilter, wat bloot hoe frekwensies
onderdruk.
Biophysia Department, UOFS, Bloemfontein.
M u t e guantitation of radionuclide dktrhhu in man with the
scidhth camera, is hampered by attenuation and scatter of photons.
When scatter correction is satisfactorily performed attenuation is
simpli6ed to narrow beam geometry. In this paper a new scatter
correction technique is introdwed. In the absence of scatter the
photopealr can be considered as a gaussian distribution and is divided m
twa identical energy windows A and B. With scattering material present,
the scatter contribution C and D is added to the m-scattered counts. If
E=A+C, F=B+D, G=A/B and H=C/D, the ,total unscattered
photopeak counts can be obtained as A+B= {(G+ l)(E-HF)}/(G-H).
Ideally, G equals 1 and H equals 3. The validity of the equation A+B was
established by determining G and H empirically and using these values to
determine the linear attenuation coefficient for an attenuated source.
~ethods] The intrinsic value of G was determined on a pixel-by-pixel
bask for Tc-99m and also with a low energy collimator mounted. Sources
filled with 10 MBq Tc-99m were imaged in varying depths of water and H
calculated from the resulting attenuation we. The effed of the scatter
correction method on resolution was furthermore determined by imaging
line sources in varying depths of water and calculating the full width at
half and tenth maximum (FWHM, FWTM).
[Results] The mean intrinsic G value was 1.07 (+0.12) and varied
between 0.76 and 151 over the total image with the extreme values mostly
on the edges. For the useful field of view the mean G value was 1.05
(kO.11). The optimum fit to the attenuation curves was found with
H= .OS. This resulted in an average linear attenuation coeffiaent of 0.1%
cm- 2 . No drastic improvement was found in FWHM of the line source,
but the scatter corredion technique resulted in a 24% improvement of
FWTM at a depth of 100 mm water.
[Discussion] A simple, accurate method to correct for scatter is described
This method can be applied to improve quantitation of radionudide
distribution on planar and SPEC3 images.
WHOLEBODY IRRADIATION FOR MYCOSIS FUNGOIDES -
AN ALTERNATIVE METHOD WITH THE PATIENT
RECUMBENT
~Botha*. ~.~nvman*.~.~illemse. G.- Huyssteen and L
~oedhals:
Departments of Oncotherapy and Biophysics , U.OF-S.,
Bloemfontein.
Electron beam radiation is very effective in the treatment of
cutaneous mycosis fungoides. When hi doses are applied it may
result in a complete response rate o S" 86 % in limited plaque
disease falling to 44 % in tumorous disease.
In current whole body irradiation techniques the patient is
required to stand erect during treatment for up to three hours.
Wepresent an alternative radiographic method where the atient
remains recumbent during treatment for approximate& two
hour<
A contour is first taken at the level of the patients' xiphoid
sternum in the prone and supine positions with arms held above
the head. Three to four treatment regions (60 X 60 cm) are then
identijied depending on the len* of the patient. The cenees are
70 cm apart and both the supenor and inferior region must extend
beyond the arms and legs respectively. Six treatment fields (4
Mev electrons) are a plied to each re on (anterior, posterior, left
and right anterior obique and left anfright postenor obhque).
For the anterior and posterior fields the patient lies on the floor
with the tube at OD, obli ue fields are applied on the treatment
table with the tube at 308 and 6' E e-shielding (lead or wax) is
utilized for the anterior fields. l'& dosimeters were used to
determine doses.
Special equipment developed includes. a "probe" to ensure
treatment regions of 60 X 60 cm, extension for the treatment table
and measuring rod (2m) to ensure a correct F.S.D..
This alternative method has been applied to 12 atients and has
proved to be both accurate and prachral, cspdafly in the case of
patients significantly weakened by the disease.
Nd: YAG LASER AS PALLIATIEWE BEHANDELING BY
BRONGUSTUI4ORE
M Pretorius*, F P J le Roux.
Afdeling Fulmonologie, Departement Interne
Geneeskunde, UOVS.
'n Studie is gedoen om die moontlikheid te
ondersoek of die Nd:YAG laser aangewend kan word
in die behandeling van endobrongiale tumore.
Pasiente met brongoskopiese en sitologiese
bevestiging van brongustumore is gebruik.
Die Nd:YAG laser werk op die beginsel van
koagulering van protexenbevattende elemente in
die weefsel.
Die laser het verskillende stadia van werking:
1. koagulering van weefsel
2. verdamping van sellulgre vog
3. verkoling van weef sel
4. verdamping van droe materie
Daar is bevind dat daar na laserterapie die
volgende waargeneem kan word:
1. Afname in tumoqnassa weens koagulering en
verdamping soos klinies waargeneem tydens
laserbehandeling.
2. Verbetering in die belugting van
parenchiemale komponente distaal tot
tumormassa soos radiologies waargeneem.
3. Verbetering in longfunksie soos
weerspieel deur vloei-volume kurwe.
4. Onmiddelike simptomatiese verligting soos
deur pasient beskryf .
A STUDY TO DETECT A POSSIBLE INTERACTION OF
IPSAPIRONE WITH HUMAN INSULIN IN TYPE I AND TYPE
I1 DIABETICS FOLLOWING SINGLE AND REPEATED
ADMINISTRATION OF IPSAPIRONE HCL
HG ~uus*, G Groenewoud, HKL Hundt, F0 Miiller en M
van Dyk.
Department of Pharmacology, University of the
Orange Free State, PO Box 339; Bloemfontein,
Republic of South Africa.
Ipsapirone, a pyrimidinyl piperazine derivative
related to buspirone, is under investigation for
its anxiolytic activity. Since diabetes is a
chronic condition, there is a strong possibility