Monte Carlo based investigations of electron contamination from telecobalt unit head in build up region and its impact on surface dose.

A Telecobalt unit has wide range of applications in cancer treatments and is used widely in many countries all around the world. Estimation of surface dose in Cobalt-60 teletherapy machine becomes important since clinically useful photon beam consist of contaminated electrons during the patient treatment. EGSnrc along with the BEAMnrc user code was used to model the Theratron 780E telecobalt unit. Central axis depth dose profiles including surface doses have been estimated for the field sizes of 0×0, 6×6, 10×10, 15×15, 20×20, 25×25, 30×30cm2 and at Source-to-surface distance (SSD) of 60 and 80cm. Surface dose was measured experimentally by the Gafchromic RTQA2 films and are in good agreement with the simulation results. The central axis depth dose data are compared with the data available from the British Journal of Radiology report no. 25. Contribution of contaminated electrons has also been calculated using Monte Carlo simulation by the different parts of the Cobalt-60 head for different field size and SSD's. Moreover, depth dose curve in zero area field size is calculated by extrapolation method and compared with the already published data. They are found in good agreement.

Resolving the brachytherapy challenges with government funded hospital.

OBJECTIVE: The objective of this study is to rationalize the feasibility and cost-effectiveness of high dose rate (HDR) cobalt 60 (Co-60) source versus 192-Iridium (192-Ir) source brachytherapy in government funded hospitals and treatment interruption gap because of exchange of sources. MATERIALS AND METHODS: A retrospective study of gynecological cancer patients, treated by radiotherapy with curative intent between April 2005 and September 2012 was conducted. We analyzed the total number of patients treated for external beam radiotherapy (EBRT) and brachytherapy (Intracavitary brachytherapy or cylindrical vaginal source). The dates for 192-Ir sources installation and the last date and first date of brachytherapy procedure before and after source installation respectively were also analyzed and calculated the gap in days for brachytherapy interruptions. RESULTS: The study was analyzed the records of 2005 to September 2012 year where eight 192-Ir sources were installed. The mean gap between treatment interruptions was 123.12 days (range 1-647 days). The Institutional incidence of gynecological cancer where radiotherapy was treatment modality (except ovary) is 34.9 percent. Around 52.25 percent of patients who received EBRT at this institute were referred to outside hospital for brachytherapy because of unavailability of Iridium source. The cost for 5 year duration for single cobalt source is approximately 20-22 lakhs while for 15 Iridium sources is approximately 52-53 lakhs. CONCLUSION: The combined HDR Co-60 brachytherapy and EBRT provide a useful modality in the treatment of gynecological cancer where radiotherapy is indicated, the treatment interruption because of source exchange is longer and can be minimized by using cobalt source as it is cost-effective and has 5 year working life. Thus, Co-60 source for brachytherapy is a feasible option for government funded hospitals in developing countries.

[Community participation improves vaccination coverage]. / La participation communautaire ameliore la couverture vaccinale.

PIP: Since 1979 in India, the health center in Malavani, a Bombay slum, has tried different methods to vaccinate the largest possible number of newborns and children. Methods used to vaccinate infants and children included clinic visits to subcenters or to a health center, vaccination of siblings of students at primary schools, visits in a designated place in the community, and home visits by a health center team with the participation of local leaders and benevolent organizations, with the participation of medical and paramedical students, by a health center team with no community participation, or by primary school students who persuaded mothers to take their children to the mobile vaccination unit. A review of the vaccination records shows that, in the case of first vaccinations for DPT (diphtheria-pertussis-tetanus) and polio conducted by door-to-door visits, follow-up vaccinations had been better and the costs lower when primary school students made home visits encouraging mothers to take their children to a mobile vaccination unit and with participation of local benevolent organizations. Overall, third dose coverage for these two vaccinations was higher with community participation (regardless of type of community participation) than without it (78% vs. 67%). Without doubt, community participation has a favorable effect on vaccination coverage.^ieng

[Community participation promotes immunization]. / La participacion comunitaria impulsa la cobertura vacunal.

PIP: In 1979, the immunization coverage of children under 5 was 40% in Malavani, a slum of Bombay with 100,000 inhabitants. During the period 1980-87 the percentage of children receiving a 3rd vaccination dose against diphtheria-pertussis-tetanus (DPT) and poliomyelitis increased from 66% in 1980 to 82% in 1983, and dropped again to 74% in 1987 resulting in an almost zero incidence of polio. Since 1979 various methods have been used to involve nursing mothers and their infants to reduce the rate of discontinuation between the 1st DPT and polio vaccination. 5 subcenters serve the weekly health care of children under 5 with vaccination, weighing, as well as the education of mothers about nutrition, immunization and family planning. 971 children obtained their vaccination with their older brothers in 3 phases in the course of 3 months. Community consultation for children under 5 and their mothers was also organized. 563 nursing infants were identified, of whom 502 received health care in the course of 6 months. 89% received DPT and antipolio vaccination. Under a scheme funded by the Aga Khan Foundation 200 children volunteers also paid door-to-door visits to 1200 families that comprised 6000 persons distributing UNICEF flyers and providing instruction in oral rehydration for diarrhea management. They achieved an 85% rate of 3rd vaccination dose completion. This grassroots community approach improved coverage at reduced costs indicating the value of voluntary community action.^ieng