Establishing a fingerprinting method for fast catheter identification in HDR brachytherapy in vivo dosimetry.

Purpose: To use quantities measurable during in vivo dosimetry to build unique channel identifiers, that enable detection of brachytherapy errors.

Materials And Methods: Treatment plan of 360 patients with prostate cancer who underwent high-dose-rate brachytherapy (range, 16-25 catheters; mean, 17) were used. A single point virtual dosimeter was placed at multiple positions within the treatment geometry, and the source-dosimeter distance and dwell time were determined for each dwell position in each catheter.

Accuracy of an electromagnetic tracking enabled afterloader based on the automated registration with CT phantom images.

Background: Electromagnetic tracking (EMT) has been researched for brachytherapy applications, showing a great potential for automating implant reconstruction, and overcoming image-based limitations such as contrast and spatial resolution. One of the challenges of this technology is that it does not intrinsically share the same reference frame as the patient's medical imaging.

Purpose: To present a novel phantom that can be used for a comprehensive quality assurance (QA) program of brachytherapy EMT systems and use this phantom to validate a novel applicator-based registration method of EMT and image reference frames for gynecological (GYN) interstitial brachytherapy.

A scintillation dosimeter with real-time positional tracking information for in vivo dosimetry error detection in HDR brachytherapy.

Purpose: To evaluate the performance of an electromagnetic (EM)-tracked scintillation dosimeter in detecting source positional errors of IVD in HDR brachytherapy treatment.

Materials And Methods: Two different scintillator dosimeter prototypes were coupled to 5 degrees-of-freedom (DOF) EM sensors read by an Aurora V3 system. The scintillators used were a 0.

A high-Z inorganic scintillator-based detector for time-resolved in vivo dosimetry during brachytherapy.

Purpose: High-dose rate (HDR) and pulsed-dose rate (PDR) brachytherapy would benefit from an independent treatment verification system to monitor treatment delivery and to detect errors in real time. This paper characterizes and provides an uncertainty budget for a detector based on a fiber-coupled high-Z inorganic scintillator capable of performing time-resolved in vivo dosimetry during HDR and PDR brachytherapy.

Method: The detector was composed of a detector probe and an optical reader.

Performance of an enhanced afterloader with electromagnetic tracking capabilities for channel reconstruction and error detection.

Purpose: To assess catheter reconstruction and error detection performance of an afterloader (Elekta Brachytherapy, Veenendaal, The Netherlands) equipped with electromagnetic (EM) tracking capabilities.

Materials/methods: The Flexitron research unit used was equipped with a special check cable integrating an EM sensor (NDI Aurora V3) that enables tracking and reconstruction capability. The reconstructions of a 24-cm long catheter were performed using two methods: continuous fixed-speed check cable backward stepping (at 1, 2.

Technical Note: Identification of an optimal electromagnetic sensor for in vivo electromagnetic-tracked scintillation dosimeter for HDR brachytherapy.

Purpose: Brachytherapy is a treatment modality which delivers large doses of radiation in a reduced number of visits. Since a small number of large dose-per-fraction is administered in high dose rate brachytherapy, ensuring the right dose is delivered is highly critical. In this work, a scintillation detector is coupled to an electromagnetic (EM) sensor (NDI, Waterloo, ON, Canada) having submillimeter positional accuracy for real-time tracking of the dosimeter position.

Technical Note: On EM reconstruction of a multi channel shielded applicator for cervical cancer brachytherapy: A feasibility study.

Purpose: Electromagnetic tracking (EMT) is a promising technology for automated catheter and applicator reconstructions in brachytherapy. In this work, a proof-of-concept is presented for reconstruction of the individual channels of a new shielded tandem (140 mm long shield) dedicated to intensity-modulated brachytherapy.

Methods: All six channels of a straight prototype were reconstructed using an electromagnetic (EM) system from Aurora (NDI, Waterloo, ON, Canada).

Influence of antituberculosis drug resistance and Mycobacterium tuberculosis lineage on outcome in HIV-associated tuberculous meningitis.

HIV-associated tuberculous meningitis (TBM) has high mortality. Aside from the devastating impact of multidrug resistance (MDR) on survival, little is understood about the influence of other bacterial factors on outcome. This study examined the influence of Mycobacterium tuberculosis drug resistance, bacterial lineage, and host vaccination status on outcome in patients with HIV-associated TBM.

Iodine status in late pregnancy and psychosocial determinants of iodized salt use in rural northern Viet Nam.

Objective: To establish iodine status among pregnant women in rural northern Viet Nam and explore psychosocial predictors of the use of iodized salt in their households.

Methods: This prospective study included pregnant women registered in health stations in randomly-selected communes in Ha Nam province. At recruitment (< 20 weeks of gestation), sociodemographic factors, reproductive health, intimate partner relationship, family violence, symptoms of common mental disorders and use of micronutrient supplements were assessed.

Multiplex allele-specific polymerase chain reaction for detection of isoniazid resistance in Mycobacterium tuberculosis.

Setting: Pham Ngoc Thach Tuberculosis Reference Hospital, Ho Chi Minh City, Viet Nam.

Design: A multiplex allele-specific polymerase chain reaction (MAS-PCR) was developed to detect mutations at the two most common sites responsible for isoniazid (INH) resistance in Mycobacterium tuberculosis: katG315 and inhA-15. The MAS-PCR is able to detect rare mutations at katG315, in addition to katG S315T.

Long-term weekly iron-folic acid and de-worming is associated with stabilised haemoglobin and increasing iron stores in non-pregnant women in Vietnam.

Background: The prevalence of anaemia and iron deficiency in women remains high worldwide. WHO recommends weekly iron-folic acid supplementation where anaemia rates in non-pregnant women of reproductive age are higher than 20%. In 2006, a demonstration project consisting of weekly iron-folic acid supplementation and regular de-worming was set up in two districts in a northern province in Vietnam where anaemia and hookworm rates were 38% and 76% respectively.

Comparison of MAS-PCR and GenoType MTBDR assay for the detection of rifampicin-resistant Mycobacterium tuberculosis.

Setting: Pham Ngoc Thach Hospital for Tuberculosis and Lung Diseases, the tertiary referral hospital for tuberculosis (TB) in Southern Vietnam.

Objective: To develop and evaluate a simple, rapid and accurate multiplex allele specific polymerase chain reaction (MAS-PCR) test to detect rifampicin (RMP) resistance point mutations at codons 516, 526 or 531 in the rpoB gene of Mycobacterium tuberculosis.

Design: The novel MAS-PCR was compared with the commercial M.

Fluoroquinolone resistance detection in Mycobacterium tuberculosis with locked nucleic acid probe real-time PCR.

Setting: Pham Ngoc Thach Hospital for Tuberculosis and Lung Diseases, Ho Chi Minh City, Vietnam.

Objective: Fluoroquinolones (FQs) are increasingly used in the treatment of tuberculosis (TB) and are the second-line drugs of choice for treatment of multidrug-resistant TB. We aimed to set up a polymerase chain reaction (PCR) based assay to detect the most common FQ-resistance-associated mutations in gyrase A (gyrA) of Mycobacterium tuberculosis.

The influence of host and bacterial genotype on the development of disseminated disease with Mycobacterium tuberculosis.

The factors that govern the development of tuberculosis disease are incompletely understood. We hypothesized that some strains of Mycobacterium tuberculosis (M. tuberculosis) are more capable of causing disseminated disease than others and may be associated with polymorphisms in host genes responsible for the innate immune response to infection.

Relationship between Mycobacterium tuberculosis genotype and the clinical phenotype of pulmonary and meningeal tuberculosis.

We used large sequence polymorphisms to determine the genotypes of 397 isolates of Mycobacterium tuberculosis from human immunodeficiency virus-uninfected Vietnamese adults with pulmonary (n = 235) or meningeal (n = 162) tuberculosis. We compared the pretreatment radiographic appearances of pulmonary tuberculosis and the presentation, response to treatment, and outcome of tuberculous meningitis between the genotypes. Multivariate analysis identified variables independently associated with genotype and outcome.

PCR-restriction fragment length polymorphism for rapid, low-cost identification of isoniazid-resistant Mycobacterium tuberculosis.

PCR-restriction fragment length poymorphism (PCR-RFLP) is a simple, robust technique for the rapid identification of isoniazid-resistant Mycobacterium tuberculosis. One hundred consecutive isolates from a Vietnamese tuberculosis hospital were tested by MspA1I PCR-RFLP for the detection of isoniazid-resistant katG_315 mutants. The test had a sensitivity of 80% and a specificity of 100% against conventional phenotypic drug susceptibility testing.

Molecular analysis of Mycobacterium tuberculosis causing multidrug-resistant tuberculosis meningitis.

Setting: Tertiary referral hospitals in southern Vietnam.

Objective: Molecular characterisation of multidrug-resistant (MDR) tuberculous meningitis (TBM).

Design: Mycobacterium tuberculosis isolates from the cerebrospinal fluid (CSF) of 198 Vietnamese adults were compared with 237 isolates from patients with pulmonary tuberculosis (PTB) matched for age, sex and residential district.

Mutations prevalent among rifampin- and isoniazid-resistant Mycobacterium tuberculosis isolates from a hospital in Vietnam.

Vietnam is ranked 13th among the WHO list of 22 high-burden countries, based upon estimated total number of tuberculosis cases. Despite having a model national tuberculosis program, consistently achieving and exceeding WHO targets for detection and cure, drug-resistant and multidrug-resistant tuberculosis cases continue to rise. Rapid multidrug-resistant tests applicable in this setting, coupled with effective treatment regimens, would be a useful tool in reversing this trend, allowing early identification of patients with multidrug-resistant tuberculosis and avoiding resistance-amplifying regimens.