How efficient is Technitium -99m labelling of erythrocytes in patients with malaria?

Date
2011
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Abstract
ENGLISH ABSTRACT: With the expansion of Nuclear Medicine techniques in developing countries, it is essential to ensure a quality imaging procedure. In the case of red cell labelling, any factor which interferes with the labelling can lead to sub-optimal studies. With regard to the high incidence of malaria in sub-Saharan African countries in general and in Cameroon particularly, a high percentage of patients referred to Nuclear Medicine departments also have malaria. The question arose whether the presence of Plasmodium in erythrocytes or anti-malarial medication could affect the labelling of erythrocytes with technetium-99m. The aim of this study was to investigate the impact of Plasmodium and anti-malarial medication on Tc-99m red cell labelling efficiency with in vitro kits in a population with a high prevalence of malaria infection. Approval for this study was obtained from ethics committees of both institutions. Three groups of 30 patients were enrolled in the study after giving informed consent: 1. Smear-negative patients in an area where malaria is endemic (control group M-). 2. Patients with malaria as determined by a positive malaria smear test (group M+). 3. Patients with malaria and on anti- malaria medication (group Mm). From each patient, a 5 ml blood sample was drawn in a heparinised blood collection tube. The red blood cells of each sample were labelled in vitro with Tc-99m, using an in vitro red blood cell kit. Labelling efficiency of the 3 groups was compared. The average labelling efficiency was 98.2% ± 2.3% in malaria-free individuals, 98.6% ± 2.6% in patients with malaria but not on treatment, and 98.6% ± 1.1% in patients with proven malaria on quinine treatment. Non parametric data analysis using the Kruskal-Wallis ANOVA test for the percentage of labelling efficiencies showed a P-value of 0.2117 which was a confirmation that there was no significant difference between the labelling efficiencies for the three groups. Radioactively labelled red blood cells are used in various nuclear medicine studies. Various drug therapies, including antibiotics, are known to either inflict direct or indirect damage to RBCs or their precursors or to impact influx or efflux of Tc-99m-pertechnetate into or out of RBCs, thereby decreasing labelling efficiency to such an extent that poor and inaccurate diagnostic information is obtained. The results of this study indicate that malaria parasites and anti-malarial treatment with quinine do not affect in vitro erythrocyte labelling with Tc-99m, and should thus not interfere with nuclear medicine investigations.
AFRIKAANSE OPSOMMING: Met die toenemende gebruik van Kerngeneeskunde in ontwikkelende lande is dit noodsaaklik om goeie kwaliteit beeldingsprosedures te verseker. In geval van rooiselmerking kan enige faktor wat met die merking inmeng tot sub-optimale studies lei. Weens die hoë insidensie van malaria in Afrikalande suid van die Sahara oor die algemeen en spesifiek in Kameroen, het hoë persentasie van pasiënte wat na Kerngeneeskunde verwys word, malaria onder lede. Die vraag het ontstaan of die teenwoordigheid van Plasmodium in rooiselle of anti-malaria medikasie die merking van rooibloedselle met tegnesium-99m kan beïnvloed. Die doel van hierdie studie was om ondersoek in te stel na die impak van Plasmodium en antimalaria medikasie op die doeltreffendheid van rooiselmerking met Tc-99m met in vitro kitsstelle in populasie met hoë voorkoms van malaria infeksie. Goedkeuring vir hierdie studie is van die etiese komitees van beide betrokke instansies verkry. Drie groepe van 30 pasiënte elk is by die studie betrek nadat hulle ingeligte toestemming gegee het: 1. Smeer-negatiewe pasiënte in gebied waar malaria endemies is (kontrole groep M-). 2. Pasiënte met malaria soos bepaal deur positiewe malaria smeertoets (groep M+). 3. Pasiënte met malaria en op anti-malaria medikasie (groep Mm). Vyf ml bloedmonster in gehepariniseerde bloedversamelingsbuis, is van elke pasiënt verkry. Die rooibloedselle van elke monster is met behulp van in vitro rooiselkitsstel met Tc-99m gemerk. Merkingsdoeltreffendheid van die 3 groepe is vergelyk. Die gemiddelde merkingsdoeltreffendheid was 98.2% ± 2.3% in malaria-vrye individue, 98.6% ± 2.6% in pasiënte met malaria maar sonder behandeling, en 98.6% ± 1.1% in pasiënte bewese malaria en op kinienbehandeling. Nie-parametriese data-analise met die Kruskal- Wallis ANOVA toets het P-waarde van 0.2117 gelewer, wat bevestig het dat daar geen betekenisvolle verskil tussen die merkingsdoeltreffendhede van die drie groepe was nie. Radioaktief gemerkte rooibloedselle word in verskeie Kerngeneeskunde studies gebruik. Dit is bekend dat verskeie middels, insluitende antibiotika of direkte of indirekte skade aan rooiselle of hul voorlopers veroorsaak, of die in- of uitvloei van Tc-99m in rooiselle beïnvloed, en sodoende die merkingsdoeltreffendheid in so mate verlaag dat swak en onakkurate diagnostiese inligting verkry word. Die resultate van hierdie studie toon dat malaria parasiete en anti-malaria behandeling met kinien nie die in vitro merking van rooibloedselle met Tc-99m beïnvloed nie, en dus nie met Kerngeneeskunde ondersoeke behoort in te meng nie.
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UCTD, Nuclear Medicine, Radiopharmacy
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