Effects of lead shielding on gamma radiation scatter energy spectrum during equine bone scintigraphy.

The main aim of this pilot study was to determine how the energy spectrum of scatter radiation emitted from horses after injection of the radiopharmaceutical Technetium-methyl diphosphonate (Tc-MDP), changed behind lead shielding of varying thicknesses (0.25 mm, 0.35 mm, and 0.

Radiosensitization Effect of Gold Nanoparticles in Proton Therapy.

The number of proton therapy facilities and the clinical usage of high energy proton beams for cancer treatment has substantially increased over the last decade. This is mainly due to the superior dose distribution of proton beams resulting in a reduction of side effects and a lower integral dose compared to conventional X-ray radiotherapy. More recently, the usage of metallic nanoparticles as radiosensitizers to enhance radiotherapy is receiving growing attention.

Outcomes from a multimodal, at-scale community-based HIV counselling and testing programme in twelve high HIV burden districts in South Africa.

Introduction: Facility-based HIV testing services (HTS) have been less acceptable and accessible by adolescents, men and key populations in South Africa. Community-based HIV counselling and testing (CBCT) modalities, including mobile unit and home-based testing, have been proposed to decrease barriers to HIV testing uptake. CBCT modalities and approaches may be differentially acceptable to men and women based on age.

Knowledge, attitudes and practices of young adults towards HIV prevention: an analysis of baseline data from a community-based HIV prevention intervention study in two high HIV burden districts, South Africa.

Background: With an HIV incidence of 1.00 skewed against women (1.51), adolescents in South Africa are at high HIV risk.

Volume-dependent dose-response of the intestinal stem cell niche and lymphoid tissue.

Background And Purpose: Plasticity of the intestinal stem cell compartment in response to radiation injury is regulated by a stem cell niche. We present here the first experimental observations of a dose-volume effect of the intestinal stem cell niche and of the solitary intestinal lymphoid tissues (SILT).

Materials And Methods: Regeneration of intestinal crypts in mice was studied following irradiation of millimetre-size jejunal sections with single doses of 6 to 24 Gy and compared to total body irradiation (TBI).

A community-based HIV counselling and testing programme found a decreasing proportion of new HIV testers in South Africa.

This article assesses the history of HIV testing among community-based HIV counselling and testing (CBCT) clients between 2014 and 2018 in 13 South African districts. Consenting clients were tested for HIV and interviewed to categorise as first-time testers or repeat testers. Of the 1 800 753 clients tested for HIV, 15.

The aetiology of severe community-acquired pneumonia requiring intensive care unit admission in the Western Cape Province, South Africa.

Background: Community-acquired pneumonia (CAP) is a common condition, with mortality increasing in patients who require intensive care unit (ICU) admission. A better understanding of the current aetiology of severe CAP will aid clinicians in requesting appropriate diagnostic tests and initiating appropriate empiric antimicrobials.

Objectives: To assess the comorbidities, aetiology and mortality associated with severe CAP in a tertiary ICU in Cape Town, South Africa.

Chromosomal radiosensitivity of triple negative breast cancer patients.

Based on clinical and molecular data, breast cancer is a heterogeneous disease. Breast cancers that have no expression of estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor 2 (HER2) are defined as triple negative breast cancers (TNBCs); luminal cancers have different expressions of ER, PR and/or HER2. TNBCs are frequently linked with advanced disease, poor prognosis and occurrence in young African women, and about 15% of the cases are associated with germline mutations.

Study on knowledge about associated factors of Tuberculosis (TB) and TB/HIV co-infection among young adults in two districts of South Africa.

South Africa ranks third among 22 high burden countries in the world. TB which remains a leading cause of death causes one in five adult deaths in South Africa. An in-depth understanding of knowledge, attitudes and practices of young people towards TB is required to implement meaningful interventions.

Linkage to care of HIV positive clients in a community based HIV counselling and testing programme: A success story of non-governmental organisations in a South African district.

Introduction: Although current data projects South Africa potentially meeting the UN target to test 90% of all people living with HIV by 2020, linking them to HIV care remains a big challenge. In an effort to increase linkage to care (LTC) of HIV positive clients an innovative collaborative intervention between two non-governmental organisations was developed and implemented between 2016 and 2017. This paper investigated the outcome of this collaborative intervention.

A novel methodology to assess linear energy transfer and relative biological effectiveness in proton therapy using pairs of differently doped thermoluminescent detectors.

A new methodology for assessing linear energy transfer (LET) and relative biological effectiveness (RBE) in proton therapy beams using thermoluminescent detectors is presented. The method is based on the different LET response of two different lithium fluoride thermoluminescent detectors (LiF:Mg,Ti and LiF:Mg,Cu,P) for measuring charged particles. The relative efficiency of the two detector types was predicted using the recently developed Microdosimetric d(z) Model in combination with the Monte Carlo code PHITS.

Social franchising of community-based HIV testing and linkage to HIV care and treatment services: an evaluation of a pilot study in Tshwane, South Africa.

Introduction: Although HIV testing services (HTS) have been successfully task-shifted to lay counsellors, no model has tested the franchising of HTS to lay counsellors as independent small-scale business owners. This paper evaluates the effectiveness of a social franchisee (SF) HTS-managed pilot project compared to the Foundation for Professional Development (FPD) employee-managed HTS programme in testing and linking clients to care.

Methods: Unemployed, formally employed or own business individuals were engaged as franchisees, trained and supported to deliver HTS services under a common brand in high HIV-prevalent communities in Tshwane district between 2016 and 2017.

SOI microdosimetry and modified MKM for evaluation of relative biological effectiveness for a passive proton therapy radiation field.

With more patients receiving external beam radiation therapy with protons, it becomes increasingly important to refine the clinical understanding of the relative biological effectiveness (RBE) for dose delivered during treatment. Treatment planning systems used in clinics typically implement a constant RBE of 1.1 for proton fields irrespective of their highly heterogeneous linear energy transfer (LET).

Reserve stem cell population in intestinal crypts found to be consistently small by analysis of in vivo clonogenic assays with a biomathematical dynamic model.

Background And Purpose: The high plasticity of the intestinal epithelium is maintained by a resilient reserve stem cell population, whose extent and biology are a matter of ongoing debate. The in vivo clonogenic assay (IVCA), presents a well established and efficient analysis of radiation insult to the intestinal crypts. However, we found that inadequate mathematical analysis over the last four decades led to systematic errors and contradictory results in estimates of radio-sensitivity and size of the reserve stem cell pool.

MICRODOSIMETRIC MEASUREMENT OF SECONDARY RADIATION IN THE PASSIVE SCATTERED PROTON THERAPY ROOM OF iTHEMBA LABS USING A TISSUE-EQUIVALENT PROPORTIONAL COUNTER.

Measurements of the dose equivalent at different distances from the isocenter of the proton therapy center at iThemba LABS were previously performed with a tissue-equivalent proportional counter (TEPC). These measurements showed that the scattered radiation levels were one or two orders of magnitude higher in comparison to other passive scattering delivery systems. In order to reduce these radiation levels, additional shielding was installed shortly after the measurements were done.

Diagnosis of Fanconi Anaemia by ionising radiation- or mitomycin C-induced micronuclei.

Fanconi Anaemia (FA) is an autosomal recessive disorder characterised by defects in DNA repair, associated with chromosomal instability and cellular hypersensitivity to DNA cross-linking agents such as mitomycin C (MMC). The FA repair pathway involves complex DNA repair mechanisms crucial for genomic stability. Deficiencies in DNA repair genes give rise to chromosomal radiosensitivity.

RENEB intercomparisons applying the conventional Dicentric Chromosome Assay (DCA).

Purpose: Two quality controlled inter-laboratory exercises were organized within the EU project 'Realizing the European Network of Biodosimetry (RENEB)' to further optimize the dicentric chromosome assay (DCA) and to identify needs for training and harmonization activities within the RENEB network.

Materials And Methods: The general study design included blood shipment, sample processing, analysis of chromosome aberrations and radiation dose assessment. After manual scoring of dicentric chromosomes in different cell numbers dose estimations and corresponding 95% confidence intervals were submitted by the participants.

RENEB intercomparison exercises analyzing micronuclei (Cytokinesis-block Micronucleus Assay).

Purpose: In the framework of the 'Realizing the European Network of Biodosimetry' (RENEB) project, two intercomparison exercises were conducted to assess the suitability of an optimized version of the cytokinesis-block micronucleus assay, and to evaluate the capacity of a large laboratory network performing biodosimetry for radiation emergency triages. Twelve European institutions participated in the first exercise, and four non-RENEB labs were added in the second one.

Materials And Methods: Irradiated blood samples were shipped to participating labs, whose task was to culture these samples and provide a blind dose estimate.

BRCA1, BRCA2 and PALB2 mutations and CHEK2 c.1100delC in different South African ethnic groups diagnosed with premenopausal and/or triple negative breast cancer.

Background: Current knowledge of the aetiology of hereditary breast cancer in the four main South African population groups (black, coloured, Indian and white) is limited. Risk assessments in the black, coloured and Indian population groups are challenging because of restricted information regarding the underlying genetic contributions to inherited breast cancer in these populations. We focused this study on premenopausal patients (diagnosed with breast cancer before the age of 50; n = 78) and triple negative breast cancer (TNBC) patients (n = 30) from the four South African ethnic groups.