published_or_final_version / abstract / toc / Surgery / Master / Master of Philosophy

Thesis (MSc)--Stellenbosch University, 2003. / ENGLISH ABSTRACT: Planar bone scintigraphy is highly sensitive but it may not be sensitive enough to detect subtle lesions in complex bony structures such as the spine. The accurate anatomic localisation of lesions in regions such as this is also limited using planar images. Single Photon Emission Computed Tomography (SPECT) results in a higher lesion contrast resulting in an improved sensitivity for the detection of subtle lesions. SPECT also enables improved lesion localisation, often valuable in distinguishing benign from malignant disease in the spine. A number of previous studies have demonstrated that the addition of SPECT of the spine significantly enhances the value of bone scintigraphy for the detection of bone metastases compared to planar imaging alone. These studies were however not done in the African context where patients typically present with more advanced disease. In a retrospective study of 576 patients with known primary tumors sent to our institution for bone scintigraphy for the diagnosis of bone metastases, we evaluated 119 patients in whom both planar imaging and SPECT were obtained. The studies were graded for the probability of metastatic disease, and the number of spinal lesions was determined with and without SPECT. The influence of adding SPECT on the interpretation of the study was determined in terms of the reported probability of metastatic disease, the exclusion and confirmation of metastatic disease, the decisiveness of interpretation, and the number of spinal lesions. The addition of SPEeT resulted in a statistically significant change in the interpretation of studies, although the actual numbers of patients affected were relatively small. SPEeT resulted in a more decisive interpretation of bone scintigraphy. There was a significant increase in the number of spinal lesions detected after the addition of SPEeT. It was concluded that although the use of SPEeT is ideal, acceptable results could be achieved using planar imaging alone in this patient population. This is particularly relevant in the African context, where SPEeT is often unavailable or scarce and in great demand. / AFRIKAANSE OPSOMMING: Planare beenflikkergrafie is hoogs sensitief, maar moontlik nie sensitief genoeg om subtiele letsels in ingewikkelde beenstrukture soos die werwelkolom aan te toon nie. Akkurate anatomiese lokalisasie van letsels in die genoemde strukture is beperk wanneer slegs planare beelde gebruik word. Enkelfoton-uitstraling Rekenaartomografie (EFERT) lewer 'n hoër letsel kontras, wat 'n verbeterde sensitiwiteit vir die opsporing van subtiele letsels tot gevolg het. EFERT lei ook tot verbeterde letsel lokalisasie, wat dikwels van waarde is om onderskeid tussen benigne en maligne siekte in die werwelkolom te tref. Reeds met 'n aantal vorige studies is aangetoon dat die toevoeging van EFERT van die werwelkolom die waarde van beenflikkergrafie in die opsporing van beenmetastases beduidend verhoog bo dié van planare beelding alleenlik. Hierdie studies is egter nie in omstandighede eie aan Afrika gedoen nie, waar pasiënte kenmerkend met gevorderde siekte voordoen. In In terugskouende studie van 576 pasiënte met bekende primêre tumore, wat na ons instelling verwys is vir beenflikkergrafie om beenmetastases op te spoor, het ons 119 pasiënte, wat beide planare beelding en EFERT ondergaan het, ge-evalueer. Die studies is gegradeer volgens die waarskynlikheid vir metastatiese siekte, en die hoeveelheid werwelkolom letsels, met en sonder EFERT, is bepaal. Die invloed van EFERT op die vertolking van die studie is bepaal in terme van die waarskynlikheid van metastatiese siekte, die bevestiging en uitskakeling daarvan, die beslistheid van vertolking, en die hoeveelheid werwelkolom letsels. Die toevoeging van EFERT het tot 'n statisties beduidende verandering in die vertolking van studies gelei, alhoewel die werklike getal pasiënte wat hierdeur geraak is, relatief min was. EFERT het 'n meer besliste vertolking van beenflikkergrafie tot gevolg gehad. Daar was 'n beduidende toename in die hoeveelheid werwelkolom letsels wat opgespoor is na die toevoeging van EFERT. Daar is tot die slotsom gekom dat, alhoewel die gebruik van EFERT wenslik is, aanvaarbare resultate met slegs die gebruik van planare beelding in hierdie pasiënt bevolkingsgroep verkry kan word. Dit is veral van belang in Afrikaomstandighede, waar EFERT dikwels onbeskikbaar of skaars is, en ook in groot aanvraag is.

A radiação ionizante prévia promove alterações actínicas em tecidos peritumorais,o que poderia influenciar a demarcação do linfonodo sentinela.O presente estudo desenvolveu modelo experimental para demarcação do linfonodo sentinela do reto do rato e para definição da dose de radiação (curva de calibração). O objetivo foi avaliar a influência da radiação ionizante pré-operatória sobre a marcação, com corante azul patente, do linfonodo sentinela do reto de ratos. A amostra foi constituída por 40 ratos machos Wistar e dividida em 2 grupos:Grupo 1 (controle não irradiado; n = 20) e Grupo 2 (irradiado com 1200cGy e demarcado 2 dias após; n = 20). Foi observado aumento linear do tempo de coloração do linfonodo no Grupo 2. Concluindo,a irradiação pré-operatória não influiu na demarcação do linfonodo sentinela do reto do rato / Previous ionizing radiation induces actinic alterations in peritumoral tissues and thus might influence the localization of the sentinel lymph node. The present study developed an experimental model for the localization of the sentinel lymph node of the rectum of the rat and for the definition of the dose of radiation (calibration curve). The objective was to evaluate the influence of preoperative ionizing radiation on the staining of a patent blue dye in the sentinel lymph node of the rectum in rats.The sample was composed of 40 male Wistar rats and was divided in two groups: Group 1 (non-irradiated control; n = 20 ) and Group 2(irradiated with 1200cGy and stained 2 days afterwards; n = 20). It was observed a linear increase in the time for the staining of the lymph in Group 2.In conclusion, preoperative irradiation did not influence the staining of the sentinel lymph node of the rectum in rats

A radiação ionizante prévia promove alterações actínicas em tecidos peritumorais,o que poderia influenciar a demarcação do linfonodo sentinela.O presente estudo desenvolveu modelo experimental para demarcação do linfonodo sentinela do reto do rato e para definição da dose de radiação (curva de calibração). O objetivo foi avaliar a influência da radiação ionizante pré-operatória sobre a marcação, com corante azul patente, do linfonodo sentinela do reto de ratos. A amostra foi constituída por 40 ratos machos Wistar e dividida em 2 grupos:Grupo 1 (controle não irradiado; n = 20) e Grupo 2 (irradiado com 1200cGy e demarcado 2 dias após; n = 20). Foi observado aumento linear do tempo de coloração do linfonodo no Grupo 2. Concluindo,a irradiação pré-operatória não influiu na demarcação do linfonodo sentinela do reto do rato / Previous ionizing radiation induces actinic alterations in peritumoral tissues and thus might influence the localization of the sentinel lymph node. The present study developed an experimental model for the localization of the sentinel lymph node of the rectum of the rat and for the definition of the dose of radiation (calibration curve). The objective was to evaluate the influence of preoperative ionizing radiation on the staining of a patent blue dye in the sentinel lymph node of the rectum in rats.The sample was composed of 40 male Wistar rats and was divided in two groups: Group 1 (non-irradiated control; n = 20 ) and Group 2(irradiated with 1200cGy and stained 2 days afterwards; n = 20). It was observed a linear increase in the time for the staining of the lymph in Group 2.In conclusion, preoperative irradiation did not influence the staining of the sentinel lymph node of the rectum in rats