7 results on '"Lahiri, Annesha"'
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2. Clinical and dosimetric consequences of imperfect applicator insertion in cervical cancer brachytherapy
- Author
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Chakrabarti, Bikramjit, primary, Pal, Suparna Kanti, additional, Sepai, Harris Mahammad, additional, Basu-Roy, Somapriya, additional, Kar, Sanjay Kumar, additional, Lahiri, Annesha, additional, Das, Sounik, additional, and Bala, Amit, additional
- Published
- 2018
- Full Text
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3. Comparison of dose volume parameters evaluated using three forward planning – optimization techniques in cervical cancer brachytherapy involving two applicators
- Author
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Chakrabarti, Bikramjit, primary, Basu-Roy, Somapriya, additional, Kar, Sanjay Kumar, additional, Das, Sounik, additional, and Lahiri, Annesha, additional
- Published
- 2017
- Full Text
- View/download PDF
4. The genetic diversity of Mycobacterium avium subsp. hominissuis
- Author
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Lahiri, Annesha
- Subjects
Non tuberculosis mycobacteria ,Germany ,Comparative genomics ,Tuberculosis ,India - Abstract
Non tuberculosis mycobacteria (NTM) are ubiquitous opportunistic environmental bacteria. Commonality of infections due to NTM in the developed countries like Germany has attained significant importance. Little is known about NTM prevalence in developing countries like India. Since Mycobacterium avium subsp. hominissuis (MAH) was identified as the most predominant NTM in clinical samples in Germany, the ecological niche of this bacterium in Germany was explored in this study and it was concluded that soil and dust may be relevant sources for MAH infections in Germany. No MAH was identified in soil and dust samples from India. Instead a plethora of different NTM residing in Indian soils (e.g. M. terrae, M. fortuitum and M. asiaticum) was identified. The study revealed that the biogeography of a place has an important role in defining the habitat and occurrence of NTM. Two draft MAH genomes from isolates from dust and from a child suffering from lymphadenitis were introduced in the public databases to facilitate better comparative genomics and understand the underlying molecular mechanisms responsible for this environmental bacterium to evolve as an opportunistic pathogen. The study also proposed a genome island in MAH which represents a highly dynamic zone. This identified dynamic region points to the opinion that the genomes of MAH are open to DNA rearrangements and the flexible gene pools have an imperative role to play in offering adaptive advantages to these microbes. The habitat of the bacteria is one important factor adding up to the list of several others like infectivity, transmission potential of the bacteria and intensity of MAH exposures that could be responsible for MAH infections. SNP analysis in three MAH genes revealed no correlation between the SNPs from MAH in different environmental and clinical habitats., Nicht-tuberkulöse Mykobakterien (NTM) sind ubiquitäre, opportunistische Umweltbakterien. In den Industriestaaten wie beispielsweise in Deutschland haben die Infektionsraten von NTM eine signifikante Bedeutung erreicht. Über die NTM-Prävalenzen in Entwicklungs- und Schwellenländern wie beispielsweise Indien ist wenig bekannt. Da Mycobacterium avium subsp. hominissuis (MAH) als das häufigste aus klinischen Proben isolierte NTM in Deutschland identifiziert wurde, wurde in der vorliegenden Arbeit die ökologische Nische dieses Bakteriums in Deutschland ermittelt und Erde und Staub als mögliche relevante Quellen für MAH Infektionen identifiziert. MAH konnte nicht aus Erd- und Staubproben aus Indien isoliert werden. Stattdessen wurde eine Fülle verschiedener NTM (z.B. M. terrae, M. fortuitum and M. asiaticum) in Erdproben aus Indien gefunden. Diese Studie konnte aufzeigen, dass die Biogeographie eines Ortes sowohl das Habitat als auch das Vorkommen von NTM entscheidend definiert. Zwei MAH draft Genome, von einem Umweltisolat aus Staub und einem Patientenisolat eines Kindes mit Lymphadenitis, wurden den öffentlichen Datenbanken hinzugefügt, um eine bessere vergleichende Genomanalyse zu gewährleisten. Dies ermöglicht ein besseres Verständnis der molekularen Mechanismen, die für die Evolution eines Umweltkeines zu einem opportunistischen Krankheitserreger verantwortlich sind. Des Weiteren wurde eine Genominsel in MAH identifiziert, die sich als stark dynamische Sequenzregion darstellt. Diese dynamische Region deutet darauf hin, dass das MAH Genom Reorganisationen unterliegt und dass diese flexiblen Genpools eine wichtige Rolle bei der Anpassung der Bakterien an Umweltveränderungen spielen. Das Habitat der Bakterien ist als wichtiger Faktor neben anderen Faktoren wie Infektiosität, Übertragungspotential und Expositionsstärke mitverantwortlich für eine MAH Infektion. Untersuchungen von drei MAH Genen mittels SNP-Analyse zeigten keine Korrelation zwischen den SNPs von MAH und dem ökologischen oder klinischen Habitat.
- Published
- 2014
5. Identification and comparative analysis of a genomic island in Mycobacterium avium subsp. hominissuis
- Author
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Lahiri, Annesha, primary, Sanchini, Andrea, additional, Semmler, Torsten, additional, Schäfer, Hubert, additional, and Lewin, Astrid, additional
- Published
- 2014
- Full Text
- View/download PDF
6. Inter-Fraction Dosimetric Variation In Point A, Bladder, Rectum During High Dose Rate Brachytherapy Treatment Of The Carcinoma Of Uterine Cervix.
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Lahiri, Annesha, Chakraborty, Bikramjit, and Pal, Santanu
- Subjects
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HIGH dose rate brachytherapy , *CERVIX uteri , *BLADDER , *RECTUM - Abstract
Inter-fraction dosimetric variation in Point A, Bladder, rectum during high dose rate brachytherapy treatment of the carcinoma of uterine cervix Dr. Sounik Das, Dr. Annesha Lahiri, Dr. Bikramjit Chakraborty, Dr. Santanu Pal IPGMER & SSKM Hospital, Kolkata Purpose - Quantification of inter-fraction percentage dose variations to point A, bladder and rectal points using Fletcher suite applicator Background - In India, every year, 122, 844 women are diagnosed with cervical cancer and 67, 477 die from the disease. Ranking as the second most common cancer among women aged 15-44 years, it becomes imperative to identify patients at an early stage, and offer the best treatment modality. Beyond FIGO stage IIA, chemoradiation followed by brachytherapy is a potentially curable treatment modality. India has developed by leaps and bounds in every discipline. Yet, huge deficit exists where radiation therapy is concerned, being mostly confined to the big cities. Further, centres offering brachytherapy to the poor are even fewer and far between. Brachytherapy is usually administered in fractionated doses over 2-4 weeks. Planning prior to each fraction takes into account the inter-fraction changes in tumour volume, anatomy, applicator placement geometry etc. Considering the huge burden of the disease, we have attempted to evaluated the validity of the plan done during first fraction when applied to subsequent fractions of brachytherapy. Materials and methods - A total of 225 patients of carcinoma cervix attended the Out Patient Department of Radiotherapy, SSKM hospital from November 2016 to July 2017. Out of these, patients receiving External Beam Radiotherapy followed by 3 fractions of HDR-Intra-cavitary Brachytherapy (Nucletron - Ir192) with Fletcher Suite applicator, to achieve a final EQD2 of 80- 90Gy to Point A were analysed and 18 patients were selected. For each patient the applicator, tandem angle, placement of OS guard, ovoids and vaginal gauze packing was kept constant throughout fractions. A pelvic CT scan was performed after each insertion, catheter reconstruction, placement of ICRU reference points, dose prescription to Point A and optimization was performed by the same team of physicist and radiation oncologist. Plans were examined retrospectively and patients undergoing improper insertion during first fraction were excluded. Of the selected patients first fraction prescription dose, dwell position and weightage was noted and applied on 2nd and 3rd fraction planning CT, thus creating a hypothetical plan which can be compared to 2nd and 3rd fraction optimized plans. Since prescribed dose was not always the same in all fractions we calculated the percentage of prescribed dose to Point A, percentage of point A dose to bladder and rectum. Hypothetical vs optimized plans' means were compared using Paired-t test with SPSS version 23. Result - 17 out of 18 patients completed 3 fraction of HDR ICBT, 1 patient after completing 2nd fraction, dropped out of 3rd fraction. Absolute mean dose of optimized plans Point A - 689.89 cGy Bladder Point - 495.42 cGy Rectal Point - 468.81 cGy Absolute mean dose of hypothetical plans Point A - 682.84 cGy Bladder Point - 573.04 cGy Rectal Point - 518.6 cGy The difference in mean percentage of prescribed dose to Point A 1st & 2nd fraction - (-)6.76 % (n=18, p= 0.348) 1st & 3rd fraction - 1.44 % (n= 17, p= 0.826) The difference in mean percentage of Point A to: Bladder 1st & 2nd fraction - 12.17 % (n=18, p= 0.00024) 1st & 3rd fraction - 11.36 % (n= 17, p= 0.026) Rectum 1st & 2nd fraction - 11.78 % (n= 18, p= 0.018) 1st & 3rd fraction - 9.12 % (n= 17, p= 0.025) Conclusions - There is no significant inter-fraction difference as far as the dose to point A is concerned. Even after recreating similar situations every time and applying the first plan to subsequent fractions, dose to point A were more or less constant and close to our prescribed dose but bladder and rectum doses were increased & statistically significant. According to EMBRACE 2015 study (ICRU report 89), rectal point estimates 20% higher dose than corresponding D2cc rectum. On the other hand, the bladder point estimates 20% lower than its D2cc dose. In a busy institute with a huge patient load where bladder and rectal points are being used instead of D2cc, time could rather be utilized in treating more number of patients per day. Thus it might be prudent to use the same plan for subsequent fractions, as statistically significant difference of dose to tumour does not exist. This will make it logistically possible to provide a potentially curable treatment to many more patients, reducing the prevalence of the disease, at least, until centers for brachytherapy are increased manifold. [ABSTRACT FROM AUTHOR]
- Published
- 2017
7. Inter-Fraction Variations Of Dose To Point A, Bladder And Rectal Points In Locally Advanced Carcinoma Cervix Patients Treated With Hdr Brachytherapy Fletcher Suite Applicator.
- Author
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Lahiri, Annesha
- Subjects
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HIGH dose rate brachytherapy , *BLADDER , *DATA plans , *CARCINOMA , *RADIOISOTOPE brachytherapy - Abstract
Purpose - Quantification of inter-fraction dose variations to point A, bladder and rectal points using Fletcher suite applicator. Background - It is a well established fact that planning prior to each ICBT fraction is an accurate method of dose delivery keeping in mind the change in applicator position, tumour volume shrinkage and change in anatomy. But in a busy institute with a huge patient load, how feasible is application of data from the plan of first fraction to subsequent fractions. Methods - A total of 46 patients of locally advanced carcinoma cervix from November 2016 to June 2017 received External Beam Radiotherapy (Bhabatron II Co60) followed by 3# of HDR-Intra-cavitary Brachytherapy (Nucletron - Ir192) with Fletcher Suite applicator, final EQD2 of 80-90Gy . For each of 3 ICBT applications same applicator and similar vaginal gauze packing was done, a pelvic CT scan was performed and dose at point A, bladder and rectal points were defined according to ICRU 38, by same physicist. Planning was done on Oncentra Brachy Treatment Planning. Variation of dose at Point A, bladder and rectal points for 1st fraction ICBT was compared with 2nd and 3rd fractions, using paired-t test. Data was analysed using SPSS Version 24. Results- 42 patients completed 3 fraction of HDR ICBT, 4 patients after completing 2nd fraction, dropped out of 3rd fraction. Difference between 1st vs 2nd fraction mean doses of: Point A 7.13 cGY (n=46, p=0.632) Bladder point 28.06 cGY (n=46, p=0.188) Rectal Point 21.06 cGY (n=46, p=0.176) Difference between 1st vs 3rd fraction mean doses of: Point A 6.22 cGy (n=42, p=0.625) Bladder point 0.81 cGy (n42, p=0.976) Rectal Point 21.18 cGy (n42, p=0.211) Conclusions - First fraction TPS planning and its use for subsequent fractions is justified as the inter-fraction differences of dose to Point A, Bladder and rectal points are statistically not significant, ensuring correct instrument placement and similar vaginal gauze packing. We also found out that the major variation was in the Bladder point dose, with minimum difference of 0.5cGy(1st vs 2nd ) maximum difference of 314.80(1st vs 3rd). Variations in Rectal dose was much lesser, minimum difference of 6.82cGY(1st vs 2nd ) and maximum difference of 199.50 cGY (1st vs 3rd) We conclude that a single plan created at the time of first fraction can be used for a single patient for three fractions, without significant variation of dose to cervix, bladder and rectum. Thus saving valuable brachytherapy OT time which can be utilised to treat other patients, specially in a country like India where Brachytherapy machines are scarce and patient load is mammoth. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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