GammaTile® brachytherapy in the treatment of recurrent glioblastomas

Background GammaTile® (GT) is a recent U.S. Food and Drug Administration (FDA) cleared brachytherapy platform. Here, we report clinical outcomes for recurrent glioblastoma patients after GT treatment following maximal safe resection. Methods We prospectively followed twenty-two consecutive Isocitrate Dehydrogenase (IDH) wild-type glioblastoma patients (6 O6-Methylguanine-DNA methyltransferase methylated (MGMTm); sixteen MGMT unmethylated (MGMTu)) who underwent maximal safe resection of recurrent tumor followed by GT placement. Results The cohort consisted of 14 second and eight third recurrences. In terms of procedural safety, there was one 30-day re-admission (4.5%) for an incisional cerebrospinal fluid leak, which resolved with lumbar drainage. No other wound complications were observed. Six patients (27.2%) declined in Karnofsky Performance Score (KPS) after surgery due to worsening existing deficits. One patient suffered a new-onset seizure post-surgery (4.5%). There was one (4.5%) 30-day mortality from intracranial hemorrhage secondary to heparinization for an ischemic limb. The mean follow-up was 733 days (range 279-1775) from the time of initial diagnosis. Six-month local control (LC6) and twelve-month local control (LC12) were 86 and 81%, respectively. Median progression-free survival (PFS) was comparable for MGMTu and MGMTm patients (~8.0 months). Median overall survival (OS) was 20.0 months for the MGMTu patients and 37.4 months for MGMTm patients. These outcomes compared favorably to data in the published literature and an independent glioblastoma cohort of comparable patients without GT treatment. Conclusions This clinical experience supports GT brachytherapy as a treatment option in a multi-modality treatment strategy for recurrent glioblastomas.

Simulation of Pressure- and Temperature-Dependent Fracturing Fluid Loss in Multi-Porosity Multi-Permeability Formations

In this paper, the multi-porosity multi-permeability porothermoelastic theory is used to derive the analytical solution to calculate the pressure- and temperature-dependent fracturing fluid loss. A triple-porosity triple-permeability source rock formation is selected as an example to illustrate the model. The effects of fracturing fluid temperature and natural fractures on the fluid loss rate are systematically illustrated. The model successfully accounts for the varying leak-off rates in the multi-permeability channels through the hydraulic fracture faces. Furthermore, thermal diffusion near the hydraulic fracture faces contributes to a variation of pore pressure whose gradient at hydraulic fracture faces directly controls the fracturing fluid leak-off rate. The model shows that thermal effects bring almost 27% variation in the leak-off rate. Comparison study indicates that the single porosity model without considering multi-permeability systems or thermal effects significantly underestimates the rate of fracturing fluid loss and predicts nearly 84% and 87% lower leak-off rate, compared to the dual-porosity dual-permeability and triple-porosity triple-permeability models, respectively. Two case studies using published laboratory measurements on naturally fractured Blue Ohio sandstone samples are conducted to show the performances of the model. It is shown that the model presented in this paper well captures the total leak-off volume during the pressure-dependent fluid loss measured from laboratory tests. Matching the analytical solution to the laboratory data also allows rocks’ double permeabilities to be estimated.

ASSESSMENT OF VARIATIONS IN SPHENOID SINUS PNEUMATIZATION IN PAKISTANI POPULATION AT TERTIARY CARE HOSPITAL. A RETROSPECTIVE MULTIDETECTOR COMPUTED TOMOGRAPHY STUDY

Aim: The aim of the study is to evaluate the role of computed tomography in identifying the various pattern of pneumatization in the sphenoid sinuses.Knowledge of pattern of pneumatization is essential for various trans-sphenoidal surgical procedures. Methodology: This is a retrospective study conducted at tertiary care hospital Lahore General Hospital Department of Diagnostic Radiology from the period of June 2020 to December 2020.The study consisted of a total of 80 patients from age group of 20 years to 70 years who were referred to the Department of Diagnostic Radiology for CT scan(PNS) .Patients of age less than 20 years , previous facial surgeries , trauma of skull base and having tumor of sphenoid sinuses were excluded. Sphenoid sinuses images were evaluated for pneumatization by posterior and anterior extensions. RESULTS: The patients included were in the age range of 20-70 year with an average age of 43.5 year in which 44 (55%) were male and 36(45) were female The pneumatization pattern observed in the sphenoid sinuses in descending order was as follows , post sellar prevalence was 75%, prevalence of sellar was 10% and 2.5% was presellar. Conchal prevelance was observed to be 0%. Conclusion: Sphenoid sinus anatomy review before trans-sphenoidal surgery is vital for safer endoscopic instrumentation of the patients . Keyword: Sphenoid sinus, pneumatization, cerebral fluid leak, endoscopy