A patient-specific quality assurance study on absolute dose verification using ionization chambers of different volumes in RapidArc treatments

The recalculation of 1 fraction from a patient treatment plan on a phantom and subsequent measurements have become the norms for measurement-based verification, which combines the quality assurance recommendations that deal with the treatment planning system and the beam delivery system. This type of evaluation has prompted attention to measurement equipment and techniques. Ionization chambers are considered the gold standard because of their precision, availability, and relative ease of use. This study evaluates and compares 5 different ionization chambers: phantom combinations for verification in routine patient-specific quality assurance of RapidArc treatments. Fifteen different RapidArc plans conforming to the clinical standards were selected for the study. Verification plans were then created for each treatment plan with different chamber-phantom combinations scanned by computed tomography. This includes Medtec intensity modulated radiation therapy (IMRT) phantom with micro-ionization chamber (0.007 cm³) and pinpoint chamber (0.015 cm³), PTW-Octavius phantom with semiflex chamber (0.125 cm³) and 2D array (0.125 cm³), and indigenously made Circular wax phantom with 0.6 cm³ chamber. The measured isocenter absolute dose was compared with the treatment planning system (TPS) plan. The micro-ionization chamber shows more deviations when compared with semiflex and 0.6 cm³ with a maximum variation of ?4.76%, ?1.49%, and 2.23% for micro-ionization, semiflex, and farmer chambers, respectively. The positive variations indicate that the chamber with larger volume overestimates. Farmer chamber shows higher deviation when compared with 0.125 cm³. In general the deviation was found to be <1% with the semiflex and farmer chambers. A maximum variation of 2% was observed for the 0.007 cm³ ionization chamber, except in a few cases. Pinpoint chamber underestimates the calculated isocenter dose by a maximum of 4.8%. Absolute dose measurements using the semiflex ionization chamber with intermediate volume (0.125 cm³) shows good agreement with the TPS calculated among the detectors used in this study. Positioning is very important when using smaller volume chambers because they are more sensitive to geometrical errors within the treatment fields. It is also suggested to average the dose over the sensitive volume for larger-volume chambers. The ionization chamber-phantom combinations used in this study can be used interchangeably for routine RapidArc patient-specific quality assurance with a satisfactory accuracy for clinical practice.     

Management of penile cancer patients during the COVID-19 pandemic: An eUROGEN accelerated Delphi consensus study

ObjectivesTo develop an international consensus on managing penile cancer patients during the COVID-19 acute waves. A major concern for patients with penile cancer during the coronavirus disease 2019 (COVID-19) pandemic is how the enforced safety measures will affect their disease management. Delays in diagnosis and treatment initiation may have an impact on the extent of the primary lesion as well as the cancer-specific survival because of the development and progression of inguinal lymph node metastases.Materials and methodsA review of the COVID-19 literature was conducted in conjunction with analysis of current international guidelines on the management of penile cancer. Results were presented to an international panel of experts on penile cancer and infection control by a virtual accelerated Delphi process using 4 survey rounds. Consensus opinion was defined as an agreement of ≥80%, which was used to reconfigure management pathways for penile cancer.ResultsLimited evidence is available for delaying penile cancer management. The consensus rate of agreement was 100% that penile cancer pathways should be reconfigured, and measures should be developed to prevent perioperative nosocomial transmission of COVID-19. The panel also reached a consensus on several statements aimed at reconfiguring the management of penile cancer patients during the COVID-19 pandemic.ConclusionsThe international consensus panel proposed a framework for the diagnostic and invasive therapeutic procedures for penile cancer within a low-risk environment for COVID-19.     

Hepatorenal Syndrome: Are We Missing Some Prognostic Factors?

Background  

Hepatorenal syndrome (HRS) is the functional renal failure associated with advanced cirrhosis and has also been described in fulminant hepatic failure. Without liver transplantation its prognosis is dismal. Our study included patients with type 1 HRS associated with cirrhosis, who were not liver transplant candidates.     

Management of upper limb arterial injury without angiography--Chennai experience

We present our experience and observations in the management of upper limb arterial injury in a tertiary trauma care centre of a University Hospital in a developing country from January 2000 to January 2002. In this retrospective study, we had treated 27 patients (identified from trauma register) with upper extremity vascular injuries. Clinical examination and Doppler pressure studies were our prime modalities of investigation. Angiography was not employed. Our immediate limb salvage rate was 100%. Two patients developed complications during a mean follow up of 70 days with one requiring amputation. We thereby emphasise the fact that good results can be obtained by thorough clinical examination and Doppler evaluation and prompt surgery without the need for angiography in upper limb vascular trauma.     

Fetal response to maternal ascariasis as evidenced by anti ascaris lumbricoides IgM antibodies in the cord blood.

The immune response of the fetus to maternal infection with Ascaris lumbricoides was studied by estimating IgG and IgM antibodies, using ELISA, in 28 paired samples of mother and cord blood. A. lumbricoides adult male, cuticle and unembryonated egg antigen was used. Toxocara canis larva antigen was used as a specificity control. Presence of IgG in the cord blood does not signify fetal response, but the presence of IgM antibodies does. IgM antibodies to Ascaris adult male antigen were present in 27 out of 28 maternal sera and 1 out of 28 cord sera. All maternal sera and only 6 cord sera showed IgM antibodies against Ascaris cuticle and 20 out of 22 maternal sera and 8 out of 22 cord sera tested, showed IgM antibodies to Ascaris unembryonated egg antigen. Sixteen out of 22 maternal sera and none out of 22 cord sera showed IgM antibody against Toxocara canis antigen, ruling out cross reaction and transplacental leak. The results of our study suggest that the Ascaris infection can spread to the fetus and elicit immune response.     

The cytoprotective role of a low-molecular-weight heparin fragment studied in an experimental model of glomerulotoxicity

Abnormal glomerular glycosaminoglycan metabolism is involved in the onset of the morphological and functional aberrations of glomerulopathies. In the present study, a heparin derivative, low-molecular-weight heparin, was tested for its ability to afford renoprotection in an established model of experimental glomerulopathy. Two groups of male albino rats of the Wistar strain (140 +/- 10 g) received a single intravenous injection of adriamycin (7.5 mg/kg) to induce glomerulopathy, and one of them received low-molecular-weight heparin (Certoparin Sodium, Troparin; 300 microg/day/rat s.c.) treatment, commencing on day 8, for a week. Urinary protein/creatinine ratio, serum albumin, urea, uric acid and creatinine clearance were evaluated. Renal cell injury was assessed in terms of renal tissue lactate dehydrogenase, aminotransferases (aspartate and alanine transaminases) and alkaline phosphatase activities, as well as renal antioxidant status (superoxide dismutase, catalase and glutathione peroxidase, reduced glutathione, vitamins E and C). The kidney tissue was subjected to histopathologic examination. Low-molecular-weight heparin significantly reduced proteinuria and improved creatinine clearance and serum albumin levels in the rats with glomerulopathy. The significant rise in serum uric acid in the rats with glomerulopathy was reversed by low-molecular-weight heparin. Altered tissue enzyme activities in response to injury, oxidative stress challenged renal antioxidant system and abnormal renal histology were observed in the untreated nephrotic rats, while low-molecular-weight heparin treatment protected the nephrotic rats against these changes. Thus, in this study, low-molecular-weight heparin was evaluated for its role in combating glomerular injury, on the basis of some salient biochemical parameters, oxidative injury indices and histologic picture. The ability of low-molecular-weight heparin to restore glomerular anatamo-functional features in this nephrotoxic condition illuminates its multi-faceted renoprotective role.     

Evidence for the presence of phosphoinositide cycle and its involvement in cellular signal transduction in the rabbit lens

In the lens, free inositol is present at high concentrations. The lens transports inositol from the extracellular source but can also synthesize inositol from glucose via inositol-1-phosphate. The inositol containing phospholipid (phosphoinositides) constitutes only 10% of the total phospholipid in the membrane and was suggested to play some key role in the cellular differentiation. Recently, one of the phosphoinositides, PIP2, was located in the epithelial cells but not in fiber cells. Prostaglandin, which uses one of the phosphoinositide metabolites, diacylglycerol, as a precursor in its biosynthesis was also found in the lens. The evidence, although scanty, do provide some clues to the possibility that lens may contain a phosphoinositide cycle similar to retina and cornea. In this study we demonstrated that rabbit lens epithelial cells could incorporate 3H-inositol into the membrane and the label accumulated in all three phosphoinositides, PI, PIP and PIP2 with PI as the predominant form. Both PI Kinase and PIP Kinase were found in the lens epithelial homogenate which incorporated (gamma-32P) ATP into PI and PIP to form their respective product, PIP and PIP2. The membrane bound PI Synthase was also demonstrated by using a cell free system. The lens cells showed distinctive response to some agonists such as Ca2+, EGF, glucagon, serotonin but not the others such as insulin, FGF. It is therefore concluded that lens epithelium cells, like other cell types has a complete and functional phosphoinositide cycle.