Update on radiation protection of the thyroid gland.

In recent years, concern about the effects of ionizing radiation on exposed individuals has led to the need to regulate and quantify the use of diagnostic and therapeutic techniques. Geopolitical events in recent times have also increased the population's perception of insecurity regarding ionizing radiation, and we increasingly face patients reluctant to undergo certain types of scans in our nuclear medicine services and, albeit less frequently, in radiology services. This article aims to summarise the extent to which ionizing radiation is present in our daily lives and how diagnostic and therapeutic procedures can affect our health, particularly from the perspective of their effects on the thyroid gland, one of the body's most radiation-sensitive organs.

Urine human papillomavirus prevalence in women with high-grade cervical lesions.

OBJECTIVE: To determine the prevalence of human papillomavirus (HPV) in urine samples from women with high-grade cervical lesions. Secondary objectives are to identify the influence of socio-demographic factors and the different genotypes with urinary HPV positivity. STUDY DESIGN: 75 women with a positive biopsy for CIN2+ were included in the study from October 2010 to July 2011. A sample of urine was collected immediately before conization at the outpatient clinic. We analyzed the presence of HPV using a PCR technique. RESULTS: The mean age of the patients was 34.8 years (range 24 to 61). All patients had histological CIN2+, of whom 54.67% had CIN3. The prevalence of HPV in urine test was 58.82% in CIN2 population versus 78.05% in CIN3 patients (p 0.072). 31 different genotypes were found. The most frequent HPV genotype was 16-HPV, which was identified in 58% of women with positive HPV-DNA in urine samples. No demographic characteristics were significantly associated to urinary HPV prevalence. CONCLUSION: Most of the patients with CIN2+ showed positive results for urine HPV test. The prevalence of positive urinary HPV test was higher for patients with CIN3. HPV urine detection could be considered as an acceptable option for high-risk population who skip regular screening programs.

Monte Carlo dosimetric study of the BEBIG Co-60 HDR source.

Although not as widespread as Ir-192, Co-60 is also available on afterloading equipment devoted to high dose rate brachytherapy, mainly addressed to the treatment of gynaecological lesions. The purpose of this study is to obtain the dosimetric parameters of the Co-60 source used by the BEBIG MultiSource remote afterloader (BEBIG GmbH, Germany) for which there are no dosimetric data available in the literature. The Monte Carlo code GEANT4 has been used to obtain the TG43 parameters and the 2D dose rate table in Cartesian coordinates of the BEBIG Co-60 HDR source. The dose rate constant, radial dose function and anisotropy function have been calculated and are presented in a tabular form as well as a detailed 2D dose rate table in Cartesian coordinates. These dosimetric datasets can be used as input data and to validate the treatment planning system calculations.

Technical note: Monte Carlo derivation of TG-43 dosimetric parameters for radiation therapy resources and 3M Cs-137 sources.

In clinical brachytherapy dosimetry, a detailed dose rate distribution of the radioactive source in water is needed in order to plan for quality treatment. Two Cs-137 sources are considered in this study; the Radiation Therapy Resources 67-800 source (Radiation Therapy Resources Inc., Valencia, CA) and the 3M model 6500/6D6C source. A complete dosimetric dataset for both sources has been obtained by means of the Monte Carlo GEANT4 code. Dose rate distributions are presented in two different ways; following the TG43 formalism and in a 2D rectangular dose rate table. This 2D dose rate table is helpful for the TPS quality control and is fully consistent with the TG43 dose calculation formalism. In this work, several improvements to the previously published data for these sources have been included: the source asymmetries were taken explicitly into account in the MC calculations, TG43 data were derived directly from MC calculations, the data radial range was increased, the angular grid in the anisotropy function was increased, and TG43 data is now consistent with the along and away dose rate table as recommended by the TG43 update.