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Biomedical subjects

D N Sharma

Publications and source records attributed to D N Sharma.

At least 19 recordsLinked to original sources
PubMed2026

Outcomes of Stage IVA Cervical Cancer Treated with Radiation Therapy: A Systematic Review and Meta-Analysis.

FIGO stage IVA cervical cancer, defined by bladder or rectal mucosal invasion without distant metastasis, is an uncommon but clinically challenging disease with limited high-quality evidence to guide management. We performed a systematic review and meta-analysis to evaluate survival outcomes, treatment-related morbidity, and prognostic factors in patients with stage IVA cervical cancer treated with definitive radiotherapy. Following PRISMA 2020 guidelines and PROSPERO registration (CRD42024602426), PubMed, Embase, and Web of Science were searched through February 2025. Eleven studies comprising 492 patients met eligibility criteria. Pooled random-effects analyses demonstrated 2-, 3-, and 5-year disease-free survival rates of 41.5% (95% CI, 28.1-55.0), 34.2% (95% CI, 21.1-47.3), and 30.9% (95% CI, 16.0-45.8), respectively. Corresponding overall survival rates were 56.0% (95% CI, 46.2-65.9), 45.9% (95% CI, 35.9-55.9), and 34.8% (95% CI, 26.4-43.3). Weighted median disease-free survival and overall survival were 15.6 and 33.6 months, respectively. The pooled incidence of vesicovaginal or rectovaginal fistula was 23.7% (95% CI, 12.9-34.6). Adverse prognostic factors included pelvic nodal involvement, hydronephrosis, rectal invasion, omission of brachytherapy, and total EQD2 below 80-85 Gy. Concurrent chemoradiation and completion of brachytherapy were consistently associated with improved outcomes. Despite curative-intent treatment, long-term survival remains poor and treatment-related morbidity substantial. Durable pelvic control remains the principal therapeutic challenge. Concurrent chemoradiation with adequate-dose brachytherapy appears essential for optimal outcomes, while future stage IVA-specific studies incorporating image-guided adaptive brachytherapy, advanced radiotherapy techniques, and systemic treatment intensification are needed to improve survival and reduce treatment-related morbidity.

Humans↗
PubMed2006

Determination of dose-build-up thickness for absorbed dose measurement in high energy electron-photon radiation at electron storage rings.

Radiation field during accidental electron beam loss near electron storage rings comprises of high-energy electrons and bremsstrahlung photons. Due to high-energy nature of the radiation, the absorbed dose is expected to build up with depth of the body of an exposed worker and hence absorbed dose measurements in 30 cm water/tissue equivalent phantom is essential. Carrying out the measurements with in such phantoms is not practically feasible for routine applications and hence the use of an equivalent solid material around the dosemeters would be convenient. Monte Carlo calculations have been carried out in order to determine the dose-build-up thickness required in copper and lead, corresponding to the maximum absorbed within 30 cm depth of water in such radiation fields. Equivalent build-up thickness calculated for a case was verified by measurement using an ion chamber detector. The results are found to be in agreement within +/-20%.

Aluminum↗
PubMed2006

Micronuclei evaluation of reduction in neoadjuvant chemotherapy related acute toxicity in locally advanced lung cancer: an indian experience.

BACKGROUND: Lung cancer is the most common cancer in the world accounting for 17.6% cancers worldwide. The AAR i n I ndian population varies f r om 0.98-15.55. The aim of t he present study was to analyze areduction in neoadjuvant chemotherapy related acute toxicity in locally advanced lung cancer (stage IIIA and III B) using Wobe Mugos E and its evaluation using micronuclei as a cytogenetic marker. Micronuclei, which are cytoplasmic fragments of DNA, have been used as a biological dosimeter to assess DNA damage. MATERIAL AND METHODS: Fourty patients of locally advanced NSCLC were randomized into two study groups between 2001-2003. One group received neoadjuvant chemotherapy using Cisplatin and Etoposide. The other group received neoadjuvant chemotherapy using Cisplatin and Etoposide along with Wobe Mugos E which is a proteolytic enzyme preparation. A study of micronuclei frequency was done pre and post chemotherapy in both groups. RESULTS: Thirty eight patients were available for final evaluation. Anemia was the most common hematological toxicity observed. Nausea and vomiting were the most common non -hematological toxicity seen. Wobe Mugos E was found to reduce the incidence of leucopenia (p = 0.005), nausea (p=0.004), vomiting (p= 0.003), sensory neuropathy (p = 0.032) and treatment related depression (p= 0.005). A reduction in micronuclei was seen in patients in patients on Wobe Mugos E. (p =0.01). CONCLUSION: Neo-adjuvant chemotherapy related acute toxicity is a major problem in patients with advanced lung cancer. A reduction in micronuclei frequency shows Wobe Mugos E to be effective in reducing chemotherapy related acute toxicity.

Carcinoma, Non-Small-Cell Lung↗
PubMed2005

Dose build up correction for radiation monitors in high-energy bremsstrahlung photon radiation fields.

Conventional radiation monitors have been found to underestimate the personal dose equivalent in the high-energy bremsstrahlung photon radiation fields encountered near electron storage rings. Depth-dose measurements in a water phantom were carried out with a radiation survey meter in the bremsstrahlung photon radiation fields from a 450 MeV electron storage ring to find out the magnitude of the underestimation. Dose equivalent indicated by the survey meter was found to build up with increase in thickness of water placed in front of the meter up to certain depth and then reduce with further increase in thickness. A dose equivalent build up factor was estimated from the measurements. An absorbed dose build up factor in a water phantom was also estimated from calculations performed using the Monte Carlo codes, EGS-4 and EGSnrc. The calculations are found to be in very good agreement with the measurements. The studies indicate inadequacy of commercially available radiation monitors for radiation monitoring within shielded enclosures and in streaming high-energy photon radiation fields from electron storage rings, and the need for proper correction for use in such radiation fields.

Algorithms↗
PubMed2005

Standardization of 192Ir solution at BARC.

A radioactive solution of 192Ir was standardized at Bhabha Atomic Research Centre (BARC) under the international intercomparison programme of the Bureau International des Poids et Measures (BIPM) by 4pibeta-gamma coincidence and 4pigamma counting techniques, which are primary and secondary methods of standardization, respectively. The activity concentration of the 192Ir solution obtained by the efficiency extrapolation technique and as reported to BIPM was 203.15 kBq g(-1) with a combined uncertainty of +/-0.3%. The activity concentration determined by 4pigamma counting was 202.88 kBq g(-1) with a combined uncertainty of +/-1.3%. These measurement results are comparable within the uncertainty limits. Detailed uncertainty budget for both the primary and secondary methods are included.

Journal Article↗
PubMed2004

Trastuzumab and docetaxel for metastatic breast cancer: an experience from a cancer centre in India.

AIMS: To study the toxicity profile and effectiveness of combination of trastuzumab and docetaxel in women with metastatic breast cancer showing HER-2 overexpression (IHC 3+). MATERIALS AND METHODS: Sixteen women with metastatic breast cancer were treated with trastuzumab (2 mg/kg every week) and docetaxel (100 mg/m2) as first-line therapy. A loading dose of 4 mg/kg trastuzumab was given on week 1. We planned to give a minimum of six cycles of docetaxel chemotherapy. RESULTS: A total of 89 cycles of docetaxel chemotherapy was given (median five cycles per patient). Median number of cycles of trastuzumab was 44 with a range of 20-71. Of the 16 patients, seven (44%) had complete response (CR), whereas five patients (31%) had partial response (PR). The overall response rate (CR+PR) was 75%. Two patients died of progressive disease, and the other two died at home, for which the cause of death could not be known. No anaphylaxis, cardio-toxicity or febrile neutropenia was observed in any patient. Overall, the toxicity was within tolerable limits. CONCLUSION: The combination of trastuzumab and docetaxel in women with metastatic breast cancer showing HER-2 overexpression (IHC 3+) is a safe and effective regimen. However, further randomised trials are needed to establish its role in metastatic breast cancer.

Adult↗
PubMed2002

Lyoluminescence and ESR correlation studies of trehalose dihydrate.

ESR studies of irradiated lyoluminescence (LL) phosphor, trehalose dihydrate showed a linear free radical growth up to a dose of 11 kGy. The LL output measured under oxygen equilibrated conditions showed an extension of the dosimetric response from 0.6 to 6 kGy. ESR spectral analysis indicates the formation of two radical species viz., 'a' and 'b' and their involvement in the LL process. The estimated free radical concentrations of radicals 'a' and 'b' were found to be 6.81 x 10(15) and 1.35 x 10(16) g(-1), respectively, for a gamma dose of 10.8 kGy.

Journal Article↗
PubMed2002

Assessment of calibration parameters for an aerial gamma spectrometry system using Monte-Carlo technique.

During a radiation emergency subsequent to a nuclear accident or weapon fallout, quick assessment of the ground contamination and the resulting exposure is of prime importance in planning and execution of effective counter measures. For an online assessment of ground contamination, it is essential to calibrate the detector system for several parameters viz. the source energy, source deployment matrix, the flight altitude and position above the contaminated surface. This article discusses the methodology to predict all the necessary parameters like photon fluence at various altitudes, the photo-peak counts in different energy windows, Air to Ground Correlation Factors IAGCF) and the dose rate at any height due to air scattered gamma ray photons. The methodology includes generation of theoretically simulated gamma spectra at a required detector position for a given source distribution on the ground using Monte-Carlo method provided by general purpose coupled neutron/photon transport code (MCNP CCC-200). Thus generated gamma spectra are analyzed to arrive at the required parameters mentioned above.

Air Pollution, Radioactive↗
PubMed2001

Lyoluminescence characteristics of trehalose dihydrate.

Lyoluminescence (LL) of trehalose dihydrate showed a linear gamma ray sensitivity in the dose range 0.1-5 x 10(2) Gy. At increased sample weight dissolved, the LL/mg showed a reduction when the microcontroller based integrated measurement system was used. The LL/mg was found to be independent of the sample weight when the instantaneous peak output observed by the electrometer amplifier on dissolution of the phosphor was taken as a measure of LL yield. The LL spectral measurement of trehalose dihydrate in luminol solution (LL sensitizer) confirms an energy transfer from the radiation induced free radicals to luminol molecule to produce light.

Journal Article↗
PubMed2001

Management of retinoblastoma with radiation.

OBJECTIVE: To evaluate the role of radiation therapy in the management of retinoblastoma. DESIGN: Retrospective analysis. METHOD: From January 1993 to March 1994, one hundred and eleven children (150 eyes) of retinoblastoma were referred for radiotherapy. The diagnosis was based on clinical examination and ocular ultrasonogram for both the eyes. The radiation treatment policy involved 40 Gy in 20 fractions over 4 weeks delivered with sedation for children under 1 year of age, 36 Gy in 9 fractions over 3 weeks under ketamine anesthesia for 1-4 years of age and for >4 years of age, a dose of 50 Gy in 25 fractions over 5 weeks. The initial tumor regression was evaluated by A and B mode ultrasonography and/or CT scan. RESULTS: The age distribution ranged from two months to six years (median - 20 months). Bilaterality was observed in 39 out of 111 cases (35%). The male to female ratio was 1.8:1. Eighty two of the 111 children were treated by definitive external beam radiation to one or both eyes. Fifteen cases received adjuvant radiotherapy after enucleation, and 14 had extensive disease for which palliative radiotherapy was offered. We observed a complete response in 54% of cases, partial response in 32%, and none in 14% of cases. Forty per cent (40%) eye survival was documented at the end of 28 months. The complication rate encountered was about 15%. CONCLUSION: Radiotherapy is an effective modality of treatment in significant number of patients with retinoblastoma. However, it requires appropriate fractionation, precise colimation and careful immobilization with general anesthesia.

Child↗
PubMed2001

Medical disorders associated with endometrial carcinoma.

UNLABELLED: From January, 1990 to December, 1995, 113 cases of endometrial carcinoma were registered. Of them, 24 patients (20%) had associated medical disorders. A total of 37 medical disorders were found in these 24 patients. The distribution was as follows: diabetes mellitus in 15 patients, hypertension in 13 patients, coronary artery disease in two, asthma in one, RBBB in one and hypothyroidism in five patients. Age of the patients ranged from 48-76 years (Median 62 years). Fifteen patients underwent surgery and rest nine were inoperable due to medical illnesses. Eleven patients received radiotherapy and four received chemotherapy. Of the two failures, one developed metastasis to lung and another to bone. No local recurrence was observed. Median survival was 20 months. Late radiation morbidity was noticed in four patients (36%), all of them were diabetic. CONCLUSION: Hypothyroidism which was unexpectedly found in five patients may also be a risk factor associated with endometrial carcinoma. This finding has never been reported in the literature and it needs to be curiously studied in future series. The risk of late radiation complications is higher in diabetic patients. Overall prognosis of endometrial carcinoma associated with medical illnesses is not very good.

Aged↗