Radiation dose imparted to patients during diagnostic radiology is of concern, since this has the potential to cause stochastic and deterministic effects. Radiation risk and work practices were evaluated for 42 patients who underwent hysteroisalpingography (HSG) examinations using digital imaging system. Dose Area Product (DAP) meter was used for measuring DAP and values obtained were used in estimating entrance surface dose (ESD), effective dose and organ dose. Patients who underwent HSG examinations were categorized into three groups depending upon their thickness. During HSG examinations, ESD varied from 0.19 mGy to 17.07 mGy, effective dose varied from 0.01 mSv to 0.95 mSv and ovarian doses varied from 0.15 mGy to 0.43 mGy, depending upon the individual thicknesses of patients. Precise collimation, selection of appropriate field sizes and use of 0.2 mm copper filler, had an effect on reduction of radiation dose imparted to patients during HSG examinations.

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Brachytherapy is the clinical use of small encapsulated radioactive sources at a short distance from the target volume for irradiation of malignant/benign tumours. In the past few decades high dose rate (HDR) brachytherapy has been developed as an alternative to low dose rate (LDR) brachytherapy. AAPM TG 43 has recommended a new protocol for dosimetry of brachytherapy sources. As per the recommended formalism, the dose to a point can be calculated from the numerical values of measurable parameters, dose rate constant, A, radial dose function, g(r), and anisotropy function, F(r,0). It has also been recommended that for the specification of the dose rate constant as well as relative dose distribution parameters liquid water be accepted as reference medium. So far, measurements of recommended dosimetry parameters of HDR192Ir sources have been reported in solid phantom materials only. We have carried out the experimental measurements of dose rate constant and radial dose function for microselectron HDR 192Ir source (dia. 1.1 mm and length 5.0 mm) in a specially designed and locally fabricated water phantom using single sensitive layer radiochromic film (Gafchromic HS). The relative depth dose (RDD) for the microselectron HDR 192Ir source was also measured using radiochromic film in water phantom to verify the RDD calculated using the brachytherapy treatment planning system (TPS). The experimentally measured values of A and g(r) for microselectron HDR192ir source are found to be in good agreement to the experimental and Monte Carlo calculated values reported in the literature for the same source within the uncertainty of measurement. The measured and TPS calculated values of RDD are also in excellent agreement to each other. This experimental study, therefore, demonstrates the suitability of radiochromic film for dosimetry of HDR 1921r source is in liquid water.

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Intracavitory brachytherapy (ICBT) plays a major role in management of malignancy of cervix uterus. The amount of dose to be delivered to tumor volume depends upon the likely doses the rectum and bladder are going to receive because high doses to rectum and bladder could result in unmanageable complications. The complications depend upon the doses received by the rectum and bladder, the volume involved and the dose rates at which doses are received. Hence there is need to measure the actual doses received by the rectum and bladder during ICBT of cervix uterus.

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In modem radiotherapy, treatment planning plays a vital role in optimal dose delivery. The treatment plan for execution should include optimal beam arrangement, minimum complexity in execution, minimum possible dose to the normal organs surrounding the tumor without jeopardizing the tumor conformity and dose. This is greatly achievable through three dimensional conformal radiation therapy. With the advent of various diagnostic tools, such as CT scan, the dose distribution to the tumor and the surrounding normal organs can be effectively computed. The tumor conformity is achieved, mainly, by using either conformal block or multi-leaf collimators of modern linear accelerators. This development of state-of-the-art three dimensional conformal radiation treatment planning in radiation therapy helps in tumor dose escalation with minimum possible acute and late morbidity and possible higher tumor control rate. This paper describes, in detail, the physical aspects and methodology of three-dimensional conformal radiation therapy.

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The accident that occurred in 1986 at the fourth unit of Chernobyl nuclear power station, in former Soviet Union, is undoubtedly one of the most serious accidents in the history of nuclear industry. A vital recommendation made by the International Nuclear Safety Advisory Group (INSAG), IAEA that went into the causes of the accident was the creation and maintenance of nuclear safety culture to improve the nuclear safety performance. It is increasingly being recognised that the promotion and maintenance of a good safety culture and careful management of organisational changes are fundamental to ensuring that nuclear and radiological safety are adequately controlled and a good basis exists to achieve continuous improvement.

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