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1.
J Indian Assoc Pediatr Surg ; 27(1): 83-90, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35261519

RESUMEN

Aim: To explore the possibility of using urinary biomarkers neutrophil gelatinase-associated lipocalin (NGAL) and kidney injury molecule-1 (KIM-1) to assess the presence of renal scars in children with Vesicoureteric Reflux (VUR). Materials and Methods: This cross-sectional study was conducted in 94 children aged 0-16 years diagnosed with VUR in the Department of Pediatric Surgery, JIPMER. Urinary biomarkers were measured using the enzyme-linked immunosorbent assay kits, normalized with urinary creatinine (Cr) and compared with severity of VUR (low grade [I and II] and high grade [III, IV, and V]), presence or absence of renal scar in VUR patients and severity of renal scar. Independent Student's t-test, Mann-Whitney U-test, and analysis of variance Kruskal-Wallis test were used for comparison, and receiver operating characteristic (ROC) curve analysis for predicting the accuracy of biomarkers in detecting the presence of renal scars. Results: The median urinary NGAL (uNGAL) value was higher in children with renal scar (1.49 ng/mL) than those without renal scar (0.58 ng/mL) and was statistically significant (<0.001). Whereas median uNGAL/Cr was higher in children with renal scar (0.07) than those without renal scar (0.03) but was not statistically significant (P = 0.06). Urinary KIM-1 and urinary KIM-1/urinary Cr (uKIM-1/Cr) was not found to be a significant predictor of renal scar. The difference of uNGAL/Cr was comparable between the grades of renal scar but was not statistically significant. On ROC curve analysis, uNGAL had area under the ROC curve (AUC) of 0.769 with 71% of both specificity and sensitivity, whereas uNGAL/Cr was found to be a poor predictor of renal scar with AUC of 0.611, 60% sensitivity, and 61.2% specificity. Conclusion: uNGAL can serve as a noninvasive marker for diagnosing the presence of renal scar in children with VUR and a multicentric more extensive cohort study may be needed to strengthen or negate its role.

2.
Am J Physiol Gastrointest Liver Physiol ; 312(5): G488-G497, 2017 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-28209601

RESUMEN

Statins are the most widely prescribed medications worldwide for the treatment of hypercholesterolemia. They inhibit the activity of 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMG-R), an enzyme involved in cholesterol synthesis in higher organisms and in isoprenoid biosynthesis in some bacteria. We hypothesized that statins may influence the microbial community in the gut through either direct inhibition or indirect mechanisms involving alterations to host responses. We therefore examined the impact of rosuvastatin (RSV) on the community structure of the murine gastrointestinal microbiota. RSV was orally administered to mice and the effects on the gut microbiota, host bile acid profiles, and markers of inflammation were analyzed. RSV significantly influenced the microbial community in both the cecum and feces, causing a significant decrease in α-diversity in the cecum and resulting in a reduction of several physiologically relevant bacterial groups. RSV treatment of mice significantly affected bile acid metabolism and impacted expression of inflammatory markers known to influence microbial community structure (including RegIIIγ and Camp) in the gut. This study suggests that a commonly used statin (RSV) leads to an altered gut microbial composition in normal mice with attendant impacts on local gene expression profiles, a finding that should prompt further studies to investigate the implications of statins for gut microbiota stability and health in humans.NEW & NOTEWORTHY This work demonstrates that rosuvastatin administration in mice affects the gastrointestinal microbiota, influences bile acid metabolism, and alters transcription of genes encoding factors involved in gut homeostasis and immunity in the gastrointestinal tract.


Asunto(s)
Microbioma Gastrointestinal/efectos de los fármacos , Microbioma Gastrointestinal/fisiología , Tracto Gastrointestinal/fisiología , Regulación de la Expresión Génica/fisiología , Factores Inmunológicos/metabolismo , Rosuvastatina Cálcica/administración & dosificación , Administración Oral , Animales , Anticolesterolemiantes/administración & dosificación , Ácidos y Sales Biliares/biosíntesis , Citocinas/metabolismo , Relación Dosis-Respuesta a Droga , Femenino , Tracto Gastrointestinal/efectos de los fármacos , Regulación de la Expresión Génica/efectos de los fármacos , Ratones , Ratones Endogámicos C57BL
4.
Indian J Physiol Pharmacol ; 57(1): 23-30, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-24020095

RESUMEN

The autonomic dysfunction has been reported in patients with (rheumatoid arthritis) RA and systemic lupus erythematosus (SLE) like connective tissue disorders and it may be due to the vasculitis of vasa nervorum and secondary amyloidosis. The pathogenesis may also have an immune component that affects autonomic functions. In the present study, three standard cardiovascular parasympathetic function tests were performed in 207 RA patients and in 106 healthy controls. 14.45% patients were presented with symptoms related to cardiovascular autonomic dysfunction. Heart rate variation to deep breathing (DBD), standing (30:15 ratio), Valsalva ratio (VR) were found to be significantly reduced in RA patients and was weakly associated with female RA patients (r = 0.165, p = 0.018) and was not correlated to disease duration, RF positivity & severity of the disease. In conclusion, this study has confirmed the presence of significant subclinical cardiovascular parasympathetic nervous dysfunction in RA patients and its positive association with female gender. Hence, inclusion of cardiovascular autonomic function tests in the routine clinical examination may be helpful in the early detection of autonomic dysfunction in RA.


Asunto(s)
Artritis Reumatoide/fisiopatología , Frecuencia Cardíaca , Sistema Nervioso Parasimpático/fisiopatología , Adulto , Enfermedades del Sistema Nervioso Autónomo/diagnóstico , Estudios de Casos y Controles , Femenino , Humanos , Masculino , Persona de Mediana Edad
5.
J Med Phys ; 47(1): 86-92, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35548027

RESUMEN

Aim: The aim of this article is to assess Tamil Nadu adult diagnostic reference levels (DRLs) by collecting radiation dose data from the four different dental modalities. Materials and Methods: The study was carried out using routine adult exposure settings in 131 intraoral, 75 panoramic, 35 cephalometric, and 10 dental cone beam computed tomography (CBCT) X-ray devices. DRLs were assessed for intraoral and extraoral (panoramic, cephalometric, and CBCT) examinations in terms of incident air kerma (Ka, i) and kerma area product (PKA), respectively. Air kerma measurements, for all dental units, were made using calibrated RTI black Piranha 557 dosimeter (RTI Electronics AB, Sweden). The dosimeter was kept at the exit cone of the X-ray tube and on the detector side of the X-ray unit for intraoral and extraoral air kerma measurements, respectively. The obtained air kerma in extraoral modalities is multiplied with the beam area to evaluate PKA. Results: The third quartile values calculated from the median for adult intraoral (mandibular molar), panoramic, cephalometric, and CBCT were 1.5 mGy, 116 mGycm2, 40 mGycm2, and 532 mGycm2, respectively. The proposed DRL in the present study was comparable to those reported in Germany, Greece, the UK, Japan, and Korea. Conclusion: This study revealed the need for dose management and radiation dose optimization, in various dental facilities in the state. It was also found that dental facilities employed with the digital type of detector are not always related to lower exposure.

6.
Phys Med ; 82: 211-218, 2021 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-33652204

RESUMEN

We propose a novel cost-effective compensator that can be used to facilitate access to IMRT in low-and-middle income countries. The compensator has the advantages of simplicity, less downtime, increased reliability and less impact on treatment quality from patient motion during treatment. Moreover, the system can be used with either a cobalt-60 unit or linear accelerator. In this Monte Carlo study, the dosimetric properties of the new compensator design have been evaluated. Results were obtained for different field sizes of cobalt teletherapy machine, and the dose was scored at 0.5 cm depth in a water phantom. The effects of compensator thickness, filling material type and shape, and field size were identified. Furthermore, the percentage depth dose and beam profiles for various field sizes and at different depths were obtained. Beam profiles show no significant signature of the beads relative to a solid compensator; in addition, they exhibit a better flatness while preserving symmetry for all field sizes. A reusable bead-based compensator appears to be feasible, and provides dose distribution similar to a solid compensator with low cost and no hazards. Our results avail the ongoing efforts to expand the reach to IMRT in low- and middle-income countries.


Asunto(s)
Radioterapia de Intensidad Modulada , Países en Desarrollo , Humanos , Método de Montecarlo , Radiometría , Dosificación Radioterapéutica , Reproducibilidad de los Resultados
7.
J Pediatr Urol ; 17(2): 234.e1-234.e7, 2021 04.
Artículo en Inglés | MEDLINE | ID: mdl-33582018

RESUMEN

INTRODUCTION: Antero-posterior trans pelvic diameter (APD) and renal scintigraphy play a significant role in the diagnosis of pelvi-ureteric junction (PUJ) obstruction and postoperative follow-up following pyeloplasty. However, the APD varies irrespective of improvement, deterioration, or preserved function in a hydronephrotic kidney and is not a reliable parameter due to various factors (hydration status, compliance, and reduction pyeloplasty). Calyx to Parenchymal Ratio (CPR) is the ratio of the depth of the calyx and parenchymal thickness measured on ultrasound (USG) in coronal image. We assessed the utility of CPR in the follow up of pyeloplasty and compared it with the commonly used APD of the pelvis and renal scintigraphy. MATERIAL AND METHODS: A prospective cohort study was done from July 2016 to October 2017. During this period 73 pyeloplasties were done, and 62 cases meeting the inclusion criteria were enrolled. All the children underwent ultrasound and Technetium-99 m Ethylene dicysteine isotope renogram (EC) scan before and after pyeloplasty. APD and CPR values were measured on USG and compared with isotope renogram outcomes in these children in the preoperative versus postoperative period. Two defined objective variables ΔAPD, percent ΔAPD and ΔCPR, percent ΔCPR were compared with categorical variables that would predict the surgical outcome as - failed, successful or equivocal. Multinomial logistic regression analysis and receiver operating curve (ROC) analysis was used to identify predictive accuracy. RESULTS: The mean (range) APD value recorded in the preoperative period was 3.67 cm (1.40-8.00 cm), which decreased to 1.67 cm (0.40-6.50) postoperatively, which was 54.2% lower (P=<0.001). The mean (range) CPR value decreased from 5.96 (1.20-20.00) in the preoperative period to 2.57 (0.43-10.90) postoperatively, which was 56.8% lower (P=<0.001). On multinomial logistic regression analysis, ΔCPR was found to be a significant predictor of outcome with an overall accuracy of 95.1%, change in CPR was a better predictor of success after pyeloplasty as compared to change in APD, which had an overall accuracy of 85.2% (p = 0.01). Further, on ROC curve analysis, we observed that ΔCPR and %ΔCPR can strongly predict successful pyeloplasty with a sensitivity of each with 96% and 98% respectively and AUC of 0.897 and 0.799 respectively. DISCUSSION: USG (APD) and renogram are the most widely used investigation in follow-up of pyeloplasty; however, APD has its own limitations like operator variability and slower improvement. CPR has the advantages that neither calyceal depth nor parenchymal thickness is directly altered during the surgery, and early resolution of calyceal dilatation and rapid parenchymal growth following pyeloplasty and thus a surgeon independent parameter. Our results have shown that ΔCPR can identify successful pyeloplasty with strong prediction than ΔAPD and thus renal scans can be avoided if there is visible improvement in CPR on follow-up. CONCLUSIONS: Our study identified a change in CPR, i.e., ΔCPR as a strong predictor of surgical outcome, as it is not influenced by extent of pelvis reduction during pyeloplasty and early to change. Using this parameter, we can avoid unnecessary repeated nuclear scans based on persistent high APD values and optimize resource utilization. We recommend the use of CPR in routine practice in the preoperative and postoperative follow-up of PUJ obstruction following pyeloplasty.


Asunto(s)
Hidronefrosis , Obstrucción Ureteral , Niño , Estudios de Seguimiento , Humanos , Hidronefrosis/diagnóstico por imagen , Hidronefrosis/cirugía , Lactante , Riñón , Pelvis Renal/diagnóstico por imagen , Pelvis Renal/cirugía , Estudios Prospectivos , Estudios Retrospectivos , Resultado del Tratamiento , Obstrucción Ureteral/diagnóstico por imagen , Obstrucción Ureteral/cirugía , Procedimientos Quirúrgicos Urológicos
8.
Pediatr Surg Int ; 26(7): 717-20, 2010 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-20512343

RESUMEN

AIMS: The standard treatment for pelviureteric junction obstruction (PUJO) has been dismembered pyeloplasty. The open surgical, Hellström procedure in which crossing polar vessels are relocated, has been an option in adult urological practice. We present our experience with laparoscopic vascular relocation in children. METHODS: Data were retrospectively gathered on all patients who underwent laparoscopic relocation of lower pole vessels (LRLPV) at our institution between July 2004 and March 2008. Follow-up ultrasounds and MAG3 were obtained. RESULTS: LRLPV was performed in 10 boys and 9 girls. Patients were between 5.8 and 15.25 years (median 9.9 years). They presented with recurrent abdominal pain (n = 17), urinary tract infections (n = 7) and haematuria (n = 3). On ultrasound, MAG3 and retrograde studies they had hydronephrosis, obstructed drainage and a normal calibre ureter with a sharp cut-off. They were further assessed at laparoscopy and were found to have aberrant lower pole crossing vessels. All underwent laparoscopic mobilization of the lower pole vessels from the region of the PUJ thereby freeing the junction and relocating them superiorly onto the anterior wall of the pelvis. The median operating time was 120 min (range 60-240 min). The median hospital stay was 2 days (range 1-3 days). They were followed up for a median period of 12 months (range 6-36 months). All patients have remained asymptomatic. Ultrasound done at 6 months showed decreased hydronephrosis. MAG3 study showed improved drainage in 17, while 1 had poor drainage. This patient remains symptom free and is under regular follow up. CONCLUSION: Laparoscopic vascular relocation is an unconventional technique in carefully selected patients with PUJO. It obviates disrupting an intrinsically normal PU junction and treats the cause rather than the effect. Our intermediate-term results are encouraging and further long-term assessment is needed.


Asunto(s)
Hidronefrosis/cirugía , Pelvis Renal/irrigación sanguínea , Laparoscopía/métodos , Procedimientos Quirúrgicos Urológicos/métodos , Adolescente , Niño , Femenino , Estudios de Seguimiento , Humanos , Pelvis Renal/cirugía , Masculino , Estudios Retrospectivos , Obstrucción Ureteral/cirugía , Procedimientos Quirúrgicos Vasculares/métodos
9.
Radiat Prot Dosimetry ; 189(4): 452-457, 2020 Jul 24.
Artículo en Inglés | MEDLINE | ID: mdl-32409823

RESUMEN

In the present study, incident air kerma has been measured, for six intraoral examinations, for establishing regional adult diagnostic reference levels (DRLs), in intraoral radiography, in Tamil Nadu, India. A total of 131 units, both digital (semiconductor-based) and analog (film-based) radiography systems, were selected for the study. The third quartile values, for the six intraoral examinations selected for the present study, ranged from 1.2 to 2.0 mGy, for the adult settings. The results showed a wide range of patient doses existing across the clinics or hospitals studied. This is the primary study for the establishment of adult intraoral DRL, in Tamil Nadu, one of the major states of the country. Similar studies will be undertaken in other major states across the country to establish national DRLs in intraoral radiography in the country.


Asunto(s)
Niveles de Referencia para Diagnóstico , Examen Físico , Adulto , Humanos , India , Dosis de Radiación , Radiografía , Valores de Referencia
10.
J Med Phys ; 45(3): 182-186, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33487931

RESUMEN

AIM: The current work aims to calculate dose area product (DAP) and to determine regional diagnostic reference level (DRL) for pediatric panoramic radiography in Tamil Nadu. MATERIALS AND METHODS: In this study, DAP was calculated after finding the product of air kerma on the detector side of scanner with the corresponding exposed area. The obtained DAP values were further analyzed, and DRL was calculated using Microsoft Excel. The study was carried out with routine pediatric exposure parameters. RESULTS: The obtained mean, range, and third quartile values for pediatric panoramic radiography are found to be 65 mGycm2, 11-148 mGycm2, and 82 mGycm2, respectively. The proposed DRL is comparable with the other countries' DRL. CONCLUSION: Based on the results of the present study, it was observed that there exists a wide difference in mean doses among the panoramic scanners. The variation in radiation doses between the clinics/hospitals and similar scanners suggests a large potential for optimization of panoramic procedures.

11.
J Med Phys ; 44(4): 292-297, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31908390

RESUMEN

AIM: The aim of this study was to calculate dose area product (DAP) and to determine diagnostic reference level (DRL) for adult panoramic procedures in Tamil Nadu. MATERIALS AND METHODS: In this study, air kerma on the front side of the secondary collimator was measured with a Black Piranha, RTI Electronics, Sweden and multiplied with the corresponding exposed area to calculate DAP. The obtained DAP values were further analyzed, and DRL was calculated using the Microsoft Excel software. The study was carried out with regular adult exposure parameters. RESULTS: The mean, range, and 3rd quartile values for 67 panoramic scanners in Tamil Nadu, India, were calculated as 94 mGycm2, 41 mGycm2-165 mGycm2, and 114.3 mGycm2, respectively. The results are comparable with other international studies. CONCLUSION: The present study suggests that further optimization can be achieved in many centers by the recruitment of professionally qualified radiographers and conducting periodic training programs on the optimization of exposure parameters. Considering this as the first study for the dental DRL assessment, further studies are suggested to establish national dental DRL in India.

12.
Med Phys ; 45(7): 3275-3286, 2018 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-29777595

RESUMEN

PURPOSE: We propose a novel compensator-based IMRT system designed to provide a simple, reliable, and cost-effective adjunct technology, with the goal of expanding global access to advanced radiotherapy techniques. The system would employ easily reusable tungsten bead compensators that operate independent of a gantry (e.g., mounted in a ring around the patient). Thereby the system can be retrofitted to existing linac and cobalt teletherapy units. This study explores the quality of treatment plans from the proposed system and the dependence on associated design parameters. METHODS: We considered 60 Co-based plans as the most challenging scenario for dosimetry and benchmarked them against clinical MLC-based plans delivered on a linac. Treatment planning was performed in the Pinnacle treatment planning system with commissioning based on Monte Carlo simulations of compensated beams. 60 Co-compensator IMRT plans were generated for five patients with head-and-neck cancer and five with gynecological cancer and compared to respective IMRT plans using a 6 MV linac beam with an MLC. The dependence of dosimetric endpoints on compensator resolution, thickness, position, and number of beams was assessed. Dosimetric accuracy was validated by Monte Carlo simulations of dose distribution in a water phantom from beams with the IMRT plan compensators. RESULTS: The 60 Co-compensator plans had on average equivalent PTV coverage and somewhat inferior OAR sparing compared to the 6 MV-MLC plans, but the differences in dosimetric endpoints were clinically acceptable. Calculated treatment times for head-and-neck plans were 7.6 ± 2.0 min vs 3.9 ± 0.8 min (6 MV-MLC vs 60 Co-compensator) and for gynecological plans were 8.7 ± 3.1 min vs 4.3 ± 0.4 min. Plan quality was insensitive to most design parameters over much of the ranges studied, with no degradation found when the compensator resolution was finer than 6 mm, maximum thickness at least 2 tenth-value-layers, and more than five beams were used. Source-to-compensator distances of 53 and 63 cm resulted in very similar plan quality. Monte Carlo simulations suggest no increase in surface dose for the geometries considered here. Simulated dosimetric validation tests had median gamma pass rates of 97.6% for criteria of 3% (global)/3 mm with a 10% threshold. CONCLUSIONS: The novel ring-compensator IMRT system can produce plans of comparable quality to standard 6 MV-MLC systems. Even when 60 Co beams are used the plan quality is acceptable and treatment times are substantially reduced. 60 Co-compensator IMRT plans are adequately modeled in an existing commercial treatment planning system. These results motivate further development of this low-cost adaptable technology with translation through clinical trials and deployment to expand the reach of IMRT in low- and middle-income countries.


Asunto(s)
Países en Desarrollo , Planificación de la Radioterapia Asistida por Computador/métodos , Radioterapia de Intensidad Modulada/métodos , Análisis Costo-Beneficio , Diseño de Equipo , Método de Montecarlo , Radiometría , Dosificación Radioterapéutica , Radioterapia de Intensidad Modulada/economía , Radioterapia de Intensidad Modulada/instrumentación
13.
J Med Phys ; 42(1): 48-54, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-28405108

RESUMEN

The aim of this article is to assess Tamil Nadu pediatric computed tomography (CT) diagnostic reference levels (DRLs) by collecting radiation dose data for the most commonly performed CT examinations. This work was performed for thirty CT scanners installed in various parts of the Tamil Nadu region. The patient cohort was divided into two age groups: <1 year, and 1-5 years. CT dose indices were measured using a 10 cm3 pencil ion chamber with pediatric head and body polymethyl methacrylate phantoms. Dose data such as volumetric CT dose index (CTDIv) and dose length product (DLP) on a minimum of twenty average-sized pediatric patients in each category were recorded to calculate a mean site CTDIv and DLP value. The rounded 75th percentile was used to calculate a pediatric DRL for each hospital, and then region by compiling all results. Data were collected for 3600 pediatric patients. Pediatric CT DRL for two age groups: <1 year (CTDIv and DLP of head [20 mGy, 352 mGy.cm], chest [7 mGy, 120 mGy.cm] and abdomen [12 mGy, 252 mGy.cm]), and 1-5 years (CTDIv and DLP of head [38 mGy, 505 mGy.cm], chest [8 mGy, 132 mGy.cm] and abdomen [14 mGy, 270 mGy.cm]) for select procedures have been calculated. Proposed pediatric DRLs of CTDIv and DLP for head procedure were lower, and for chest and abdomen procedures were higher than European pediatric DRLs for both age groups.

14.
J Med Phys ; 40(3): 170-5, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26500404

RESUMEN

In the present work, a pediatric head and body phantom was fabricated using polymethyl methacrylate (PMMA) at a low cost when compared to commercially available phantoms for the purpose of computed tomography (CT) dosimetry. The dimensions of head and body phantoms were 10 cm diameter, 15 cm length and 16 cm diameter, 15 cm length, respectively. The dose from a 128-slice CT machine received by the head and body phantom at the center and periphery were measured using a 100 mm pencil ion chamber and 150 mm CT dose profiler (CTDP). Using these values, the weighted computed tomography dose index (CTDIw) and in turn the volumetric CTDI (CTDIv) were calculated for various combinations of tube voltage and current-time product. A similar study was carried out using standard calibrated phantom and the results have been compared with the fabricated ones to ascertain that the performance of the latter is equivalent to that of the former. Finally, CTDIv measured using fabricated and standard phantoms were compared with respective values displayed on the console. The difference between the values was well within the limits specified by Atomic Energy Regulatory Board (AERB), India. These results indicate that the cost-effective pediatric phantom can be employed for CT dosimetry.

15.
J Med Phys ; 39(1): 50-5, 2014 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-24600173

RESUMEN

Computed tomography (CT) scanner under operating conditions has become a major source of human exposure to diagnostic X-rays. In this context, weighed CT dose index (CTDIw), volumetric CT dose index (CTDIv), and dose length product (DLP) are important parameter to assess procedures in CT imaging as surrogate dose quantities for patient dose optimization. The current work aims to estimate the existing dose level of CT scanner for head, chest, and abdomen procedures in Pudhuchery in south India and establish dose reference level (DRL) for the region. The study was carried out for six CT scanners in six different radiology departments using 100 mm long pencil ionization chamber and polymethylmethacrylate (PMMA) phantom. From each CT scanner, data pertaining to patient and machine details were collected for 50 head, 50 chest, and 50 abdomen procedures performed over a period of 1 year. The experimental work was carried out using the machine operating parameters used during the procedures. Initially, dose received in the phantom at the center and periphery was measured by five point method. Using these values CTDIw, CTDIv, and DLP were calculated. The DRL is established based on the third quartile value of CTDIv and DLP which is 32 mGy and 925 mGy.cm for head, 12 mGy and 456 mGy.cm for chest, and 16 mGy and 482 mGy.cm for abdomen procedures. These values are well below European Commission Dose Reference Level (EC DRL) and comparable with the third quartile value reported for Tamil Nadu region in India. The present study is the first of its kind to determine the DRL for scanners operating in the Pudhuchery region. Similar studies in other regions of India are necessary in order to establish a National Dose Reference Level.

16.
Gulf J Oncolog ; 1(13): 30-41, 2013 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-23339979

RESUMEN

PURPOSE: To investigate enlargement of prostate volume by edema during brachytherapy seed implantation and develop a nomogram model to calculate air-kerma strength (AKS) required for implantation of the enlarged transient prostatic volume. MATERIALS AND METHODS: The prostate volume was measured prior and after seed implantation using trans-rectal ultrasound imaging in the operating room to obtain volume enlargement. A nomogram model was developed that calculates AKS required for implantation of the enlarged transient prostate volume with optimal dose coverage. RESULTS: The measured prostate enlargement in this study was up to 60% of the initial volume. The effective prostatic volume enlargement was calculated for three isotopes: 125I, 103Pd and 131Cs. The effective volume enlargement for 125I implants was relatively small (< 10%) because of its long half-life. For 103Pd and 131Cs with short half-lives, additional AKS up to 20% and 30%, respectively, might be required to provide appropriate dose coverage of possible enlarged prostatic volumes. CONCLUSIONS: Prostate volume enlargement should be considered to obtain optimal dose coverage particularly for short half-life isotopes such as 131Cs and 103Pd. The nomogram model developed in this work provides the AKS required for implants with a wide range of prostatic volume enlargements (5-100%) for three isotopes. KEYWORDS: prostate brachytherapy, nomogram, airkerma strength, edema, volume enlargement.


Asunto(s)
Radioisótopos de Yodo , Neoplasias del Cuello Uterino , Médula Ósea , Braquiterapia , Humanos , Paladio , Neoplasias de la Próstata/radioterapia , Dosificación Radioterapéutica , Estudios Retrospectivos
17.
J Cancer Res Ther ; 9(3): 422-9, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-24125977

RESUMEN

CONTEXT: Possible benefits of inverse planning. AIMS: To analyze possible benefits of inverse planning intensity modulated radiation therapy (IMRT) over field-in-field 3D conformal radiation therapy (FIF-3DCRT) and to evaluate the differences if any, between low (6 Million Volts) and high energy (15 Million Volts) IMRT plans. MATERIALS AND METHODS: Ten patients with squamous cell carcinoma of oropharynx, previously treated with 6 MV step and shoot IMRT were studied. V100, V33, V66 , mean dose and normal tissue complication probabilities (NTCP) were evaluated for parotid glands. Maximum dose and NTCP were the parameters for spinal cord. STATISTICAL ANALYSIS USED: A two-tailed t-test was applied to analyze statistical significance between the different techniques. RESULTS: For combined parotid gland, a reduction of 4.374 Gy, 9.343 Gy and 7.883 Gy were achieved for D100, D66 and D33, respectively in 6 MV-IMRT when compared with FIF-3DCRT. Spinal cord sparing was better in 6 MV-IMRT (40.963 ± 2.650), with an average reduction of maximum spinal cord dose by 7.355 Gy from that using the FIF-3DCRT technique. The uncomplicated tumor control probabilities values were higher in IMRT plans thus leading to a possibility of dose escalation. CONCLUSIONS: Though low-energy IMRT is the preferred choice for treatment of oropharyngeal cancers, FIF-3DCRT must be given due consideration as a second choice for its well established advantages over traditional conventioan technique.


Asunto(s)
Neoplasias Orofaríngeas/radioterapia , Planificación de la Radioterapia Asistida por Computador/métodos , Radioterapia de Intensidad Modulada , Relación Dosis-Respuesta en la Radiación , Humanos , Estadificación de Neoplasias , Neoplasias Orofaríngeas/patología , Dosificación Radioterapéutica , Estudios Retrospectivos
18.
J Neurosci Rural Pract ; 3(1): 84-6, 2012 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-22346205

RESUMEN

Neurocysticercosis is a common tropical infection presenting with neurological signs. It commonly presents as seizures but various other focal neurological presentations have been reported. Though neurocysticercosis have been reported to present as isolated internuclear ophthalmoplegia, we report the first case of neurocysticercosis presenting as wall-eyed monoocular internuclear ophthalmoplegia syndrome with contraversive ocular tilt reaction.

19.
J Med Phys ; 36(1): 29-34, 2011 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-21430856

RESUMEN

The goal of the present study was to study the effects of low- and high-energy intensity-modulated photon beams on the planning of target volume and the critical organs in cases of localized prostate tumors in a cohort of 8 patients. To ensure that the difference between the plans is due to energy alone, all other parameters were kept constant. A mean dose volume histogram (DVH) for each value of energy and for each contoured structure was created and was considered as completely representative for all patients. To facilitate comparison between 6-MV and 15-MV beams, the DVH-s were normalized. The different parameters that were compared for 6-MV and 15-MV beams included mean DVH, different homogeneity indices, conformity index, etc. Analysis of several indices depicts more homogeneous dose for 15-MV beam and more conformity for 6-MV beam. Comparison of all these parameters showed that there was little difference between the 6-MV and 15-MV beams. For rectum, 2 to 4 % more volume received high dose with the 6-MV beam in comparison with the 15-MV beam, which was not clinically significant, since in practice much tighter constraints are maintained, such that Normal Tissue Complication Probability (NTCP) is kept within 5 %. Such tighter constraints might increase the dose to other regions and other critical organs but are unlikely to increase their complication probabilities. Hence the slight advantages of 15-MV beam in providing benefits of better normal-tissue sparing and better coverage cannot be considered to outweigh its well-known risk of non-negligible neutron production.

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