Exploring light confinement in laser-processed LYSO:Ce for photon counting CT application

With the goal of developing a low-cost scintillator-based photon counting detector (PCD) with high dose efficiency suitable for CT, the light transport characteristics in LYSO:Ce detectors containing laser induced optical barriers (LIOB) are simulated. Light confinement and light collection efficiencies (LCE) are studied for a variety of optical barrier patterns and properties (refractive index (RI) and barrier/crystal interface roughness). Up to 80% confinement is achievable with a simple pixel pattern with one barrier wall separating each pixel coupled one-to-one to a photodetector (PD) pixel. Confinement is heavily dependent on barrier properties, and rough interfaces and higher RI results in increased cross-talk. Three approaches to enhance performance beyond the basic pattern are explored: (1) Multiple barrier walls separating each crystal pixel. (2) Introduction of long and short range confinement by having multiple crystal pixels per PD pixel. (3) Combination of LIOB and laser ablation (LA). (1) Is effective for rough interfaces where confinement can be increased by up to 24% for double compared to single walls. (2) Results in high confinement in the pixel centered on the PD pixel, but lower confinement closer to the PD edge. This feature may be explored to achieve spatial resolution beyond the PD pixel size using light sharing based positioning algorithms. (3) Can increase confinement for smooth interfaces using a smooth ablation in the bottom part of the crystal. A general trend across all configurations is a trade-off between light confinement and LCE. The LCE attainable is found comparable to that for mechanically pixelated arrays. While the confinement achievable with LIOB is always lower compared to a mechanically pixelated array, the former may offer a high level of flexibility in terms of detector design. This, in combination with the possibility to fabricate sub-mm pixels in a cost-effective manner, makes LIOB a promising technology for scintillator-based PCDs.

Solitary ulnar shortening osteotomy for malunion of distal radius fractures: experience of a centre in the UK and review of the literature

INTRODUCTION

Isolated ulnar shortening osteotomies can be used to treat ulnocarpal abutment secondary to radial shortening following distal radius fractures. Given the increase of fragility distal radius fractures awareness of treating the sequelae of distal radius fractures is important. We present the largest reported case series in the UK of ulnar shortening osteotomies for this indication.

MATERIALS AND METHODS

Twenty patients with previous distal radial fractures were included, who presented with wrist pain and radiologically evident positive ulnar variance secondary to malunion of the distal radius with no significant intercalated instability. Patients were treated with a short oblique ulnar shortening osteotomy, using a Stanley jig and small AO compression plate system. Pre- and postoperative radiographical measurements of inclination, dorsal/volar angulation and ulnar variance were made. Patients were scored pre- and postoperatively using the Quick Disabilities of the Arm, Shoulder and Hand (QuickDASH) and Patient-Rated Wrist Evaluation scores by two orthopaedic surgeons. Mean follow-up was 24 months after surgery.

RESULTS

Radiographical analysis revealed a change in the ulnar variance with an average reduction of 5.74 mm. Mean preoperative scores were 61.1 (range 25-95.5) for QuickDASH and 70.4 (range 33-92) for Patient-Rated Wrist Evaluation. At the latest follow-up, mean postoperative QuickDASH scores were 10.6 (range 0-43.2) and 17.2 (range 0-44) for Patient-Rated Wrist Evaluation. Differences in scores after surgery for both QuickDASH and Patient-Rated Wrist Evaluation were statistically significant (P < 0.01).

CONCLUSIONS

The ulnar shortening osteotomy is a relatively simple procedure compared with corrective radial osteotomy, with a lower complication profile. In our series, patients showed significant improvement in pain and function by correcting the ulnar variance thus preventing ulna-carpal impaction.

An instrumented glove for monitoring hand function

The measurement of hand kinematics is important for the assessment and rehabilitation of the paralysed hand. The traditional method of hand function assessment uses a mechanical or electronic goniometer placed across the joint of interest to measure the range of joint movement. Mechanical goniometers are imprecise and lack the ability to provide a dynamic measurement; electronic goniometers are expensive and cumbersome to use during therapy. An alternative to the goniometric based assessment is to use inertial motion sensors to monitor the hand movement-these can be incorporated in a glove. In this paper, we present the design of an instrumented glove equipped with Magnetic, Angular Rate and Gravity (MARG) sensors for the objective evaluation of hand function. The instrumented glove presented in this paper is designed to assess the range of movement of the hand and also monitor the hand function during the course of hand rehabilitation. Static and dynamic calibrations were performed for the Euler angles calculated from the MARG sensors. The results are also presented for physiological flexion/extension of the wrist (relative roll), flexion/extension of elbow (relative pitch), and internal rotation/external rotation (relative yaw). The static calibration results gave mean absolute errors of 4.1° for roll, 4.0° for pitch, and 4.6° for yaw. From the dynamic calibration, the speed of response to a step change gave a convergence time of 0.4 s; sinusoidally oscillating movement gave good tracking at 0.2 Hz but exhibits overshoot errors at higher frequencies which were tested to be 1 Hz. We present the results of the calibration of the instrumented glove (one sensor pair measuring one joint angle) measuring anatomical joint angles-mean absolute errors during static calibration: 6.3° for a relative roll (wrist flexion/extension), 5.0° for relative pitch (elbow flexion/extension), and 4.5° for relative yaw (shoulder internal rotation/external rotation). The experimental results from the instrumented glove are promising, and it can be used as an alternative to the traditional goniometer based hand function assessments.

An instrumented object for hand exercise and assessment using a pneumatic pressure sensor

Measurement of grip force is important for both exercise training and assessment of the hand during physical rehabilitation. The standard method uses a grip dynamometer which measures the force between the fingers and opposing thumb. The primary limitation of the grip dynamometer is the restriction of measurement to cylindrical grasps. Any deformation of the hand due to muscular or skeletal disease makes the grip dynamometer difficult or impossible to use. An alternative to the grip dynamometer is a sealed pneumatic object that can be gripped by the hand. Measurement of the internal pressure in the object can be related to the grip force. In this paper, we analyze such a pneumatic pressure sensing object for hand grip assessment and also describe an easy fabrication of the grip sensor. The instrumented object presented in this paper is designed to assess both the maximal voluntary grip forces and continuous grip force to monitor control of hand function during exercise under instruction from a therapist. Potential uses of such a pneumatic pressure sensing object for hand grip are in physical rehabilitation of patients following paralysing illnesses like stroke and spinal cord injury.

Novel use of bioelectric impedence technique to detect alterations in body composition in advanced small cell lung cancer

BACKGROUND

Malnutrition is frequent in lung cancer and is measured using various tools, including the novel bioelectric impedance technique for measuring body composition. However, the validation of this technique for assessing body composition in advanced small cell lung cancer (SCLC) is untested.

METHODS

Forty-one treatment naïve patients (all males) and an equal number of age- and sex-matched controls were evaluated by anthropometric measurements of skinfold thicknesses and body composition parameters such as body fat%, fat mass, fat-free mass (FFM), and total body water (TBW).

RESULTS

The mean (SD) age of the patient group was 55.7 (7.5) years, median pack-years was 20 (range, 0-80), and mean (SD) duration of symptoms was 152.6 (153.7) days. Median Karnofsky Performance Scale was 70 (range, 50-90). Majority of our patients (68.3%) were Stage IV followed by Stage III (31.7%). The percentage of patients with low, normal, and high body mass index (BMI) was 31.7%, 61%, and 7.3%, respectively. All components of body composition, i.e., body fat%, FFM, and TBW were significantly lower in patients compared to controls. However, the body composition in patients and controls with normal BMI was similar. The phenomenon of sarcopenia as a cause of cancer cachexia may explain these findings, whereas the combination of loss of body fat and lean body mass may lead to weight loss and reduced BMI.

CONCLUSION

Our results indicate that body composition is markedly altered in Indian patients with advanced SCLC. The impact of these parameters on clinically relevant outcomes needs further evaluation.

Accidental acetamiprid poisoning in a buffalo

Acetamiprid is a first generation systemic neonicotinoid insecticide, routinely used for crop protection against sucking type insects. It is likely to be of low toxicity in mammals but severe poisoning may occur if ingested in large amount. A case of buffalo with accidental ingestion of acetamiprid was presented with severe gastrointestinal symptoms and respiratory distress. The patient was managed successfully with symptomatic and supportive treatment. As far as the present report is concerned, it is the first report of acute acetamiprid poisoning in buffalo from India. From this report it is concluded that awareness programs about safe use of pesticides should be implemented.

Quality of Sleep and Sleep Disorders in Patients with Parkinsonism: A Polysomnography Based Study from Rural South India

OBJECTIVE

The objective of this study is to study the quality of sleep, sleep disorders, and polysomnographic profile in Parkinsonism patients from rural areas and to correlate polysomnographic profile with the staging of disease and with sleep questionnaire.

MATERIALS AND METHODS

Between May 2014 and December 2015, 168 Parkinsonism patients were prospectively screened using sleep questionnaire; Epworth Sleepiness Scale (ESS), Pittsburgh Sleep Quality Index (PSQI), Parkinson Disease Sleep Score-2 (PDSS-2). Sixty patients underwent overnight polysomnography subsequently.

RESULTS

The mean age of 168 patients in the study was 65.3 ± 12.8 years. The mean duration of Parkinsonism was 4.6 ± 3.1 years. The mean ESS, PSQI and PDSS-2 were 12.4 ± 3.2, 7.9 ± 2.1 and 44.7 ± 5.8, respectively. A total of 148 patients (88.1%) had poor quality sleep, which was reported only in 37 patients (22%). Excessive daytime sleepiness (80%) and insomnia (76.7%) were most common symptoms. Polysomnographic profile showed poor sleep efficiency (median interquartile range [IQR] 74.8% [17.8%-99.5%]), reduced slow wave sleep (median [IQR] 0% [0%-9.5%]), and reduced rapid eye movement [REM] sleep (median (IQR) 4.9% [0.1%-24.2%]). Sleep disorders in the study were sleep fragmentation (n = 60, 100%), obstructive sleep apnea syndrome (n = 40, 66.7%), central sleep apnea syndrome (n = 6, 10%), and periodic limb movement disorder (n = 52, 86.7%). Two patients had REM sleep behavioral disorder clinically. There was statistically significant positive correlation between staging of disease, sleep latencies, and sleep questionnaire.

CONCLUSION

Sleep is impaired in majority of Parkinsonism patients which needs to be diagnosed early and managed effectively. Patient education and awareness programs in rural areas regarding sleep disorders in Parkinsonism are required for early diagnosis.

18F-Fluorodeoxyglucose Positron Emission Tomography-computed Tomography in Evaluation of Large Vessel Vasculitis

18F-fluorodeoxyglucose positron emission tomography-computed tomography (18F-FDG PET-CT) is a rapidly evolving hybrid imaging technique in evaluation of infection and inflammation. Usually, functional changes often precede anatomical changes. 18F-FDG PET-CT, a noninvasive diagnostic test and it is useful for the early detection of inflammation. Most of the large vessel vasculitis patients present with nonspecific signs and symptoms, which are difficult to diagnose clinically. Here, we discuss three cases of large vessel vasculitis with different clinical presentations, identified by 18F-FDG PET-CT scan.

Use of fat transfer to treat a chronic, non-healing, post-radiation ulcer: a case study

OBJECTIVE

Problematic wound healing and ulceration in radiation-damaged tissue is a surgical challenge. Clinical studies have shown that grafting fat tissue in an irradiated area can improve the quality of the skin and has regenerative effects. This case study describes how fat transfer led to the healing of a chronic ulcer resistant to other forms of treatment.

CASE HISTORY

A 67-year-old lady with a chronic, non-healing ulcer in her leg had a squamous cell carcinoma excised, followed by radiotherapy. Despite multiple excisions, the ulcer continued to cause symptoms. Following an initial procedure in which fat was infiltrated around and under the ulcer, the patient underwent a wide local excision and split-thickness skin grafting. Histology demonstrated a post-radiation dermatitis ulcer with no evidence of malignancy. After a period of management with dressings showing a reduction in ulcer size, more fat was infiltrated around the lesion. Two months later, the ulcer had fully healed and has not recurred.

CONCLUSION

The use of adipose-derived stem cells to heal wounds in irradiated tissue has been the focus of research for some time. This case highlights the potential of adipose tissue to improve damaged skin. Its use could negate the need for complex surgical procedures.

Scintigraphic Profile of Thyrotoxicosis Patients and Correlation with Biochemical and Sonological Findings

INTRODUCTION

Thyrotoxicosis is a spectrum of disorder with a rather common clinical presentation with different aetiologies. The aetiological diagnosis is important as the management differs. It is essential to accurately diagnose the cause before starting treatment. Scintigraphy of thyroid helps in differentiating accurately the various causes. USG is routinely being advocated and T3/T4 ratio has also been used.

AIM

This study aims to evaluate the scintigraphic profile of thyrotoxicosis patients and to correlate biochemical and USG findings with scintigraphy.

MATERIALS AND METHODS

A total of 60 newly diagnosed thyrotoxicosis patients based on biochemical reports were included in the study. They underwent further evaluation with ultrasonography and 99mTc scintigraphy.

RESULTS

Of 60 patients of thyrotoxicosis, 45 cases were of Grave's disease, 10 cases were of thyroiditis and five cases were of Toxic Multinodular Goiter (MNG). The clinical characteristics were helpful in establishing the diagnosis in only six (10%) patients who presented with classic features of Grave's disease with ophthalmopathy. T3/T4 ratio greater than 20 was seen only in 29 (66%) patients of Grave's disease and also in three (33.33%) of thyroiditis patients. USG had a sensitivity and specificity of 81.82% and 93.75% in diagnosing Graves' disease and 100% and 82.4% in diagnosing thyroiditis respectively.

CONCLUSION

Clinical findings do not help in accurately delineating aetiological diagnosis of thyrotoxicosis. Serum T3/T4 ratio when used as a criterion has marked overlap between the various conditions causing thyrotoxicosis. USG has reasonable sensitivity however, misses many cases of early Grave's disease. Follow up scintigraphy helps in a small population with resolving thyroiditis or early Grave's disease where the initial scintiscan is normal or inconclusive.