Quantitative evaluation of the dosimetric effects of balloon deformation and source position in high-dose rate mammosite breast brachytherapy

PURPOSE

To investigate quantitatively the deformation of the mammosite balloon, eccentricity of the source position and their effects on the dose delivered to the tumor lumpectomy site and critical structures.

MATERIALS AND METHODS

The distances of the brachytherapy source to the surface of the mammosite balloon were measured in using radiographic images for fractions 1 to 10 for twelve patients. The dose at the balloon surface (nearly 680cGy) and prescription dose of 340cGy at 1cm from the balloon surface were calculated for the different fractions and their dependence on the balloon volume and source position were investigated.

RESULTS

The position of the source can be offset from the center of the mammosite balloon by up to 6mm. Deformation of the balloon led to variations in its dimensions by up to 8mm. The dose at 1cm from the balloon surface that covers the lumpectomy site varied by up to 19% from 340cGy along the elongated diameter of the balloon and by up to 40% along the short diameter. Maximal doses to the skin, ribs and lung were 420cGy, 630cGy and 500cGy per fraction, respectively, which depended mostly on their distance from the balloon surface.

CONCLUSION

The geometric variations in the shape of the balloon and position of the source can cause lack of dose coverage to the lumpectomy site or create hot dose spots in the surrounding normal tissue that might compromise intended clinical goals. Users as well as vendors should consider correction measures for the deformation of the balloons and the eccentricity of the position of the high dose source.

Quantitative evaluation of correlation of dose and FDG-PET uptake value with clinical chest wall complications in patients with lung cancer treated with stereotactic body radiation therapy

The aim of this study was to investigate quantitatively the dosimetric factors that increase the risk of clinical complications of rib fractures or chest wall pain after stereotactic body radiation therapy (SBRT) to the lung. The correlations of clinical complications with standard-uptake values (SUV) and FDG-PET activity distributions from post-treatment PET-imaging were studied. Mean and maximum doses from treatment plans, FDG-PET activity values on post-SBRT PET scans and the presence of clinical complications were determined in fifteen patients undergoing 16 SBRT treatments for lung cancer. SBRT treatments were delivered in 3 to 5 fractions using 5 to 7 fields to prescription doses in the range from 39.0 to 60.0 Gy. The dose and FDG-PET activity values were extracted from regions of interest in the chest wall that matched anatomically. Quantitative evaluation of the correlation between dose deposition and FDG-PET activity was performed by calculating the Pearson correlation coefficient using pixel-by-pixel analysis of dose and FDG-PET activity maps in selected regions of interest associated with clinical complications. Overall, three of fifteen patients developed rib fractures with chest wall pain, and two patients developed pain symptoms without fracture. The mean dose to the rib cage in patients with fractures was 37.53 Gy compared to 33.35 Gy in patients without fractures. Increased chest wall activity as determined by FDG-uptake was noted in patients who developed rib fractures. Enhanced activity from PET-images correlated strongly with high doses deposited to the chest wall which could be predicted by a linear relationship. The local enhanced activity was associated with the development of clinical complications such as chest wall inflammation and rib fracture. This study demonstrates that rib fractures and chest wall pain can occur after SBRT treatments to the lung and is associated with increased activity on subsequent PET scans. The FDG-PET activity provides a useful parameter that can be used clinically to predict chest wall complication in lung patients.

Gross tumour volume variations in primary non-small-cell lung cancer during the course of treatment with stereotactic body radiation therapy

INTRODUCTION

We aim to quantify the variations in the gross tumour volume (GTV) during a course of stereotactic body radiotherapy (SBRT) and determine its impact on dosimetric coverage of the GTV.

METHODS

The GTVs and dose coverage for 14 patients with 16 primary non-small-cell lung tumours treated with SBRT were investigated. Initial GTVs were calculated from treatment planning CT scans. The prescribed doses ranged from 48 to 60 Gy in three to five fractions. Before each treatment, patients underwent a CBCT scan. For each CBCT scan, the GTV and the dose received by the GTV were determined and followed during the course of therapy.

RESULTS

There was considerable variation in the measured GTVs during the course of therapy. Increases of up to 63.3% of volume measured by initial CBCT were detected during the first few fractions, after which GTV tended to decrease. Dose coverage (V95) for any given fraction deviated no more than 5% from optimised coverage obtained in the initial treatment plan. In the long term, all patients with follow-up scans demonstrated tumour shrinkage with no radiographic evidence of tumour recurrence.

CONCLUSION

GTV, as evaluated in this study, demonstrates an initial increase in volume followed by a subsequent decrease. This volume change needs to be considered in the design of treatment plans and assignment of treatment margins.

Temporal changes in pregnancy-associated glycoproteins across different stages of gestation in the Barbari goat

The objective of this study was to characterize the temporal profile of pregnancy-associated glycoproteins (PAGs; isoforms 1-11) across different stages of gestation in the Barbari goat. Placentae were collected from local abattoir, classified according to crown rump length of the corresponding foetus into five groups (0-30, 31-60, 61-90, 91-120, and 121-150 days of gestation), and used for relative quantification of mRNA expression by Pfaffl method. In addition, adult female goats (pregnant, n = 7; non-pregnant, n = 5) were used to estimate weekly plasma PAG and progesterone (P4) concentrations. The relative mRNA expression of PAGs was greater (p<0.05) during 31-60 days of gestation, which correlated well with the temporal changes in plasma PAG concentrations. Relative expression of PAGs decreased steadily as gestation advanced with minimum expression observed just before parturition, except for PAG-4 and PAG-8 that showed constantly higher expression throughout pregnancy. Plasma PAG and P4 concentrations showed a distinct temporal pattern with a significant increase beginning at 2 weeks and return to basal levels by 20 weeks of gestation. However, PAG concentrations reached a peak earlier in gestation (8 weeks) than P4 (10-14 weeks). Correlation analysis indicated a strong positive association (r = 0.748, p<0.01) between plasma PAG and P4 concentrations. In conclusion, results of this study indicate a distinct temporal pattern of PAG expression and secretion during gestation in the Barbari goat. The temporal changes in PAGs and the positive association with P4 are suggestive of their role in maintenance of pregnancy and progressive foetal development.

Primary cutaneous posttransplant lymphoproliferative disorders in solid organ transplant recipients: a multicenter European case series

Primary cutaneous posttransplant lymphoproliferative disorders (PTLD) are rare. This retrospective, multicenter study of 35 cases aimed to better describe this entity. Cases were (re)-classified according to the WHO-EORTC or the WHO 2008 classifications of lymphomas. Median interval between first transplantation and diagnosis was 85 months. Fifty-seven percent of patients had a kidney transplant. Twenty-four cases (68.6%) were classified as primary cutaneous T cell lymphoma (CTCL) and 11 (31.4%) as primary cutaneous B cell PTLD. Mycosis fungoides (MF) was the most common (50%) CTCL subtype. Ten (90.9%) cutaneous B cell PTLD cases were classified as EBV-associated B cell lymphoproliferations (including one plasmablastic lymphoma and one lymphomatoid granulomatosis) and one as diffuse large B cell lymphoma, other, that was EBV-negative. Sixteen (45.7%) patients died after a median follow-up of 19.5 months (11 [68.8%] with CTCL [6 of whom had CD30(+) lymphoproliferative disorders (LPD)] and 5 [31.2%] with cutaneous B cell PTLD. Median survival times for all patients, CTCL and cutaneous B cell PTLD subgroups were 93, 93, and 112 months, respectively. Survival rates for MF were higher than those for CD30(+) LPD. The spectrum of primary CTCL in organ transplant recipients (OTR) is similar to that in the general population. The prognosis of posttransplant primary cutaneous CD30(+) LPD is worse than posttransplant MF and than its counterpart in the immunocompetent population. EBV-associated cutaneous B cell LPD predominates in OTR.

Liquid gallium-lead mixture phase diagram, surface tension near the critical mixing point, and prewetting transition

Quite recently, we reported a semianalytical equation of state (EOS) for the Ga-Pb alloy [Phys. Rev. B 78, 024205 (2008)], which was based on the first-order perturbation theory of fluid mixtures, within the simplified random phase approximation, in conjunction with the Grosdidier et al. model pair potentials for Ga-Ga and Pb-Pb with a suitable nonadditive pair potential between Ga-Pb unlike pairs. In the present work, we employ the present EOS to calculate the Ga-Pb phase diagram along the immiscibility gap region. The accuracy of the EOS is tested by consulting the empirical binodal curve. A statistical-mechanical-based theory for the surface tension is employed to obtain an analytical expression for the alloy surface tension. We calculated the surface tension along the bimodal curve and at extreme conditions of temperatures and pressures. The surface tension exhibits reasonably well the prewetting transition of Pb atoms at the surface of the Ga-rich liquid alloy and could qualitatively explain the prewetting phenomena occurring in the Ga-rich side of the phase diagram. The predicted prewetting line and wetting temperature qualitatively agree with the empirical measurements.

A Clinically Severe Variant of β-Mannosidosis, Presenting with Neonatal Onset Epilepsy with Subsequent Evolution of Hydrocephalus

β-Mannosidosis results from a functional deficiency of the lysosomal enzyme, β-mannosidase. While being a well recognised, naturally occurring disease in both goats and cattle, it is an extremely rare disorder in humans with the first cases only being recorded in 1986. Until now the severity of the human disease has not mirrored that of its bovine or caprine counterparts, whose presentation is typically in the neonatal period with both altered skull morphology and seizures. Human β-mannosidosis has previously appeared to be a more indolent disease, with its only consistent phenotypic feature being developmental delay of varying severity. We report a patient, homozygous for a private mutation, who presented in the immediate perinatal period with seizures and who subsequently developed communicating hydrocephalus at 2 years of age.These are two new phenotypic features for β-mannosidosis. The first being the neonatal onset of the seizures, for while seizures have been seen in 3 out of the previous 20 documented cases, they have never before manifested prior to 6 months of age. However, as in the previous documented cases, the seizures were difficult to control and were associated with severe developmental delay.The second unique feature about this case was the development of communicating hydrocephalus. We discuss the possible mechanisms of its development.In summary, β-mannosidosis must thus now be considered in the differential diagnosis of neonatal onset seizures, and the potential for the development of hydrocephalus should be monitored during subsequent clinical follow-up.

Ketotifen Fumarate and Salbutamol Sulphate Combined Transdermal Patch Formulations: In vitro release and Ex vivo Permeation Studies

The present work was performed to develop and evaluate transdermal patches of combined antiasthmatic drugs (salbutamol sulphate and ketotifen fumarate). Polyvinyl alcohol membrane was used as backing membrane and eudragit RL-100 was used as matrix material to suspend the drugs in the continuous thickness of the patch. Methanol was solvent and propylene glycol was used as plasticizer. Tween 20, isopropyl myristate, eucalyptus oil, castor oil and span-20 were used as permeability enhancers. Thickness, weight variation and drug uniformity were investigated. The patch formulations were also subjected to drug release in dissolution media and permeation through rabbit skin. Effects of different enhancers were evaluated on release and permeation of drugs. F3 formulations having isopropyl myristate as permeation enhancer, showed maximum amounts of drugs release (88.11% of salbutamol sulphate and 88.33% of ketotifen fumarate) at the end of 24 h dissolution study. F3 also showed maximum permeation of both drugs (4.235 mg salbutamol sulphate and 1.057 mg ketotifen fumarate) after 24 h permeation study through rabbit skin mounted in Franz cell. The patches having no enhancer in the formulation also showed some drug release and permeation due to the presence of plasticizer. The results of the study suggested that new controlled release transdermal formulations of combined antiasthmatic drugs can be suitably developed as an alternate to conventional dosage forms.

Dosimetric consideration of transient volume enlargement induced by edema in prostate brachytherapy seed implants

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; air-kerma strength; edema; volume enlargement.

Phase diagram and thermodynamic properties of H2

A statistical mechanical-based theory is used to develop the equation of state for the molecular fluid of H(2). We incorporate in this equation the long-range correlations through the double Yukawa potential, dimerization of the H(2) molecule by treating the fluid as a hard convex body fluid, and first-order quantum correction which is important at low temperatures. We use this to calculate the liquid-vapor equilibrium of H(2), including the temperature and pressure dependence of compressibility factor, entropy, specific heat, compressibility, and sound velocity.

Comparative analysis of case screening with varying cough duration and sputum samples for diagnosis of tuberculosis in patients attending the OPD at a tertiary care hospital at Srinagar, India

RESEARCH QUESTION

Can we minimize cough duration and number of sputum samples in chest symptomatic patients for screening of TB?

OBJECTIVE

To evaluate cough of 3 weeks versus 2 weeks duration using two sputum samples versus three samples in chest symptomatic patients attending the OPD.

STUDY DESIGN

Hospital-based cross-sectional study.

MATERIALS AND METHODS

Outpatients (2810) with H/O cough of 3 weeks and 2 weeks duration were screened by subjecting them to sputum microscopy for tuberculosis using two sputum samples as well as three samples following standard procedure for sputum collection, staining and acid-fast bacillus (AFB) identification. Those on drugs were not included.

RESULTS

Using ≥2 weeks cough, sputum positivity rate was 12%, nearly as high as the sputum positivity among patients with ≥3 weeks cough, i.e. 14%. First sputum smear alone on an average could detect 91.8% cases, while the first two sputum smears could detect on an average 96% cases. The study showed that maximum number of cases was diagnosed by only two sputum smears and added diagnostic value of third specimen was small, i.e. 4%.High sputum positivity rate using ≥2 weeks cough with two sputum samples was seen.

CONCLUSION

The sensitivity analysis of the study showed that using ≥2 weeks cough with two sputum samples gives almost similar values as ≥3 weeks cough with three sputum samples, but this needs further confirmatory results of culture sensitivity. Hence, using ≥2 weeks cough with two sputum samples as the diagnostic criteria for screening of cough patients for TB should be recommended as one way of improving efficient use of scarce resources.

Increased expression of gelatinase-a and timp-2 in primary human glioblastomas

The highly invasive growth of glioblastomas may be a consequence of an abnormal profile of proteinases and proteinase inhibitors involved in remodeling of the basement membrane and normal vasculature. We have detected a 1.5-3-fold increase in the transcription of gelatinase A and TIMP-2 (Tissue Inhibitor of Metalloproteinase) in glioblastomas as compared to the normal brain tissue. Increased expression of gelatinase A and TIMP-2 in these tumors was also evident by immunohistochemical analysis. Our data suggest that increased expression and perturbation of the balance between metalloproteinases and their inhibitors that are involved in extracellular matrix remodeling and angiogenesis may contribute to the invasive phenotype of glioblastomas.