Novel dosimetry verification solutions for advanced radiation therapy

Improved optimisation of radiation dose delivery to tumours with improved sparing of normal tissues is an ongoing goal of radiotherapy practice. Advanced radiotherapy techniques are constantly improving to achieve this goal. However, these techniques are more complex to deliver. Hence verifying the source of dose errors is increasingly challenging. Accurate verification of treatment delivery for advanced radiotherapy becomes increasingly important in mitigating dose delivery errors which may compromise clinical outcome. This dissertation investigated treatment dosimetry verification for two different radiotherapy delivery systems i) Open gantry linear accelerator and ii) Helical TomoTherapy HI-ART ® (HT). Part (i) Open gantry linear accelerator - novel prototype hybrid EPID based dosimeters were developed for treatment verification to combine geometric and dosimetric verification in a single system. Initial work on dose response for standard EPIDs provided a more consistent understanding of EPID under-dose response for small monitor units (MUs). The dose response linearity of a standard a-Si EPID was evaluated for different combinations of linac, image acquisition settings and imaging data processing methods. EPID nonlinear response was demonstrated to be primarily due to gain ghosting affects in the a-Si photodiodes. This work has resolved some of the inconsistencies in the literature regarding EPID dose response and proposes a simple yet robust pixel-to-dose calibration method for EPID-based IMRT dosimetry..

Study of Orthopedic Morbidities among Postmenopausal Women in a Medical College Hospital in Rural Area of Western Maharashtra, India

Introduction: It is estimated that a total of 130 million Indian women are expected to live beyond menopause by 2015. Health of postmenopausal women is of growing concern because of increased longevity and various morbidities associated with old age. Objectives: 1) To assess various orthopedic problems among postmenopausal women in rural area. 2) To estimate magnitude of common orthopedic problems and associated sociodemographic factors. Methodology: A cross-sectional study was conducted at the medical college hospital in rural area of Western Maharashtra on 500 postmenopausal women availing healthcare in a medical college hospital. Data was collected with the help of predesigned questionnaire by interview technique and with the help of case records available from orthopedic department. Results: Backache (62%) and osteoarthritis (51.6%) were common orthopedic problems. Osteoarthritis was significantly associated with obesity

Comparison of four dimensional computed tomography and magnetic resonance imaging in abdominal radiotherapy planning

Background and Purpose: Four-dimensional (4D) computed tomography (CT) is widely used in radiotherapy (RT) planning and remains the current standard for motion evaluation. We assess a 4D magnetic resonance imaging (MRI) sequence in terms of motion and image quality in a phantom, healthy volunteers and patients undergoing RT. Materials and Methods: The 4D-MRI sequence is a prototype T1-weighted 3D gradient echo with radial acquisition with self-gating. The accuracy of the 4D-MRI respiratory sorting based method was assessed using a MRICT compatible respiratory simulation phantom. In volunteers, abdominal viscera were evaluated for artefact, noise, structure delineation and overall image quality using a previously published four-point scoring system. In patients undergoing abdominal RT, the tumour (or a surrogate) was utilized to assess the range of motion on both 4D-CT and 4D-MRI. Furthermore, imaging quality was evaluated for both 4D-CT and 4D-MRI. Results: In phantom studies 4D-MRI demonstrated amplitude of motion error of less than 0.2mm for five, seven and ten bins. 4D-MRI provided excellent image quality for liver, kidney and pancreas. In patients, the median amplitude of motion seen on 4D-CT and 4D-MRI was 11.2mm (range 2.8-20.3 mm) and 10.1mm (range 0.7-20.7 mm) respectively. The median difference in amplitude between 4D-CT and 4D-MRI was −0.6mm (range −3.4-5.2 mm). 4D-MRI demonstrated superior edge detection (median score 3 versus 1) and overall image quality (median score 2 versus 1) compared to 4D-CT. Conclusions: The prototype 4D-MRI sequence demonstrated promising results and may be used in abdominal targeting, motion gating, and towards implementing MRI-based adaptive RT

An Unusual Case of Unilateral Multifocal Choroiditis in a Young Male

Multifocal choroiditis is a vision‑threatening disease causing inflammation at the level of retinal pigment epithelium and outer retina. We present a unique case of unilateral multifocal choroiditis in a young nonmyopic male and its subsequent course. The patient developed visual loss due to the sub‑retinal neovascular membrane (SRNVM) in macula due to multifocal choroiditis. The SRNVM regressed with repeated intra‑vitreal injection of bevacizumab and the visual acuity improved from 6/24 at presentation to 6/12 after repeated intra‑vitreal injections of bevacizumab.Keywords: Bevacizumab, multifocal choroiditis, sub‑retinal neovascular membran

History of rheumatology

This article describes the history and various milestones of rheumatology from ancient to modern times. The origin of rheumatology can be traced to ancient times. Diseases such as gout and osteoarthritis were prevalent in ancient people. Many ancient skeletons show signs of gout and osteoarthritis. The ancient book on Indian Medicine, Charaka Samhita, gives a vivid description of many variants of arthritis. Charaka, an eminent Ayurvedic physician, described rheumatoid arthritis (RA) in Charaka Samhitha as "Vishkantha," meaning painful joints. The word rheumatology has its origin in the word "rheuma," which means flowing, and is mentioned in Hippocratic corpus. Hippocrates made several observations about gout, popularly known as "aphorisms of gout." Many famous paintings in the medieval era depict joint diseases. Hand lesions resembling those of RA are found in paintings of the Flemish school. "The virgin with canon van der paele," a painting by Jan Van Eyck (1436), shows thickened arteries in the temple, suggestive of temporal arthritis. The famous portrait of Federigo de Montefeltre, thought to have been painted by Joos (Justus) van Gent, shows arthritis of the proximal interphalangeal joint of the left index finger. Rheumatology developed as a well-recognized specialty of medicine in the 20th century. American Physicians Bernard Comroe and Joseph Lee Hollander coined the term rheumatologist in 1940. Rheumatology has rapidly advanced during the last 50 years due to improved diagnosis as a result of progress in immunology, molecular biology, genetics and imaging

Study of Central Corneal Thickness (CCT) bBefore and aAfter Small-Incision Cataract Surgery (SICS) and phacoemulsification surgery

Purpose: To highlight the importance of measurement of central corneal thickness (CCT) which is an indirect indicator of corneal endothelial dysfunction after cataract surgery. Materials and Methods: This was a randomised control trial involving 101 patients who presented with cataract. Cataracts were graded using Lens Opacities Classification system grading. Fifty-one patients underwent small incision cataract surgery (SICS) and 50 underwent phacoemulsification (PHACO). Patients with any other ocular pathology were excluded. Results: There was significant improvement in the best corrected visual acuity (BCVA) comparable in both groups. There was a statistically  significant increase in central corneal thickness on day 7th and 30th post op. The change in the CCT and BCVA was comparable between SICS and PHACO on day 30th post op. Conclusion: The increase in CCT suggests that there was some endothelial cell loss leading to change in corneal thickness but not to the extent of causing visual impairment. SICS and phacoemulsification surgery are  comparable in respect to visual rehabilitation. Manual SICS is still a safe and cost-effective option in the developing world. Proper case selection, diligent surgery, and adequate postoperative care are essential to maintain a clear cornea.Keywords: Cataract, CCT, phacoemulsification, SIC

Commissioning of SharePlan: the liverpool experience

SharePlan is a treatment planning system developed by Raysearch Laboratories AB to enable creation of a linear accelerator intensity modulated radiotherapy (IMRT) plan as a backup for a Tomotherapy plan. A 6MV Elekta Synergy Linear accelerator photon beam was modelled in SharePlan. The beam model was validated using Matrix Evolution, a 2D ion chamber array, for two head-neck and three prostate plans using 3%/3mm Gamma criteria. For 39 IMRT beams, the minimum and maximum Gamma pass rates are 95.4% and 98.7%. SharePlan is able to generate backup IMRT plans which are deliverable on a traditional linear accelerator and accurate in terms of clinical criteria. During use of SharePlan, however, an out-of-memory error frequently occurred and SharePlan was forced to be closed. This error occurred occasionally at any of these steps: loading the Tomotherapy plan into SharePlan, generating the IMRT plan, selecting the optimal plan, approving the plan and setting up a QA plan. The out-of-memory error was caused by memory leakage in one or more of the C/C++ functions implemented in SharePlan fluence engine, dose engine or optimizer, as acknowledged by the manufacturer. Because of the interruption caused by out-of-memory errors, SharePlan has not been implemented in our clinic although accuracy has been verified. A new software program is now being provided to our centre to replace SharePlan

STUDY AND ANALYSIS OF SUSPENSION FOR SPLENDOR PLUS TWOWHEELER USING ANSYS SOFTWARE

In this paper design modification of suspension spring has been studied. This study has been done on Hero Honda splendorvehicle.In this paper, design and analyze the performance of Shock absorber by varying the wire diameter of the coil spring has been carried out. The Shock absorber which is one of the Suspension systems is designed mechanically to handle shock impulse and dissipate kinetic energy. It reduces the amplitude of disturbances leading to increase in comfort and improved ride quality. The spring is compressed quickly when the wheel strikes the bump. The compressed spring rebound to its normal dimension or normal loaded length which causes the body to be lifted. The spring goes down below its normal height when the weight of the vehicle pushes the spring down. This, in turn, causes the spring to rebound again. The spring bouncing process occurs over and over every less each time, until the up-and-down movement finally stops. The vehicle handling becomes very difficult and leads to uncomfortable ride when bouncing is allowed uncontrolled. Hence, the designing of spring in a suspension system is very crucial. The analysis isdone by considering bike mass, loads, and no of persons seated on bike. Comparison is done by varying the wire diameter of the coil spring to verify the best dimension for the spring in shock absorber. Modeling and Analysis is done using CATIA and ANSYS respectively

Step-by-step dacryocystorhinostomy for beginners: An expert′s view

Chronic dacryocystitis occurs usually due to obstruction of lacrimal passage at the junction of the lacrimal sac and the nasolacrimal duct or within the bony nasolacrimal duct. Reconstruction of the lacrimal passages in such cases can be achieved by several surgical techniques, although external dacryocystorhinostomy (DCR), proposed by Ohm and by Dupuy-Dutemps and Bourguet in 1921, is still the most successful operation. Despite ease and decreased morbidity of endonasal DCR, external DCR is procedure of choice as it is more successful. Several ophthalmologists fear performing DCR because of bleeding and unfamiliarity of structure. This article tries to provide few tips to make DCR easy and stress-free. Proper case selection, pre-operative workup and adequate exposure go a long way in making DCR stress-free and successful. Excessive bleeding, a common hindrance in DCR surgery can be successfully tackled by proper positioning of patient, use of adrenaline, suction, and adjustment of nasal pack