Measurement of Collimator Scatter Factor for Photon Fields Using Gafchromic EBT2 Film and Ion Chamber

Background and Objective: In radiotherapy, measurement of the output factor in the air is one of the input parameters for Implementation of treatment planning systems and beam modeling. The aim of this study is to design a mini-phantom and select the appropriate detector for measuring the output factor. Subjects and Methods: In-air output factor was measured for Siemens linear accelerator 6 MV energy and field sizes of 4, 6, 8, 10, 15, 2 cm irradiated by 200MU. Measurements were performed using a Gafchromic film EBT2 and 0.6 cc Farmer ion chamber and then the results were compared with Report of AAPM Therapy Physics Committee Task Group 74. For lateral electron equilibrium and electron contamination removal, two top of the water and Cerrobend were designed for film dosimetry and plexiglass buildup cap for Farmer chamber was applied. Results: The output factor increases with field size, and this increase in Cerrobend top is less than water top and Farmer dosimeter. In comparison between the results reported by TG74 and this study shows that film dosimetry with water top and Farmer chamber have 0.35 and 0.68 mean percentage differences with TG74 respectively and meanwhile the film dosimetry with Cerrobend top presents 1.48 mean percentage differences. Conclusion: EBT2 film with mini phantom made of water as a good alternative to ion chamber dosimeters known as a standard dosimeter especially the film can be used for a wider range of field size

DOES IN VIVO LIGAMENT FORCE PASS THROUGH LIGAMENT INSERTIONS?: A ROBOTIC STUDY

INTRODUCTION Post traumatic osteoarthritis (PTOA) is a subset of osteoarthritis that arises after traumatic joint injury. Approximately half of patients suffering from anterior cruciate ligament (ACL) injuries have been shown to progress towards PTOA within fifteen years[1]. One of the areas of research for PTOA is examining the biomechanical changes following an ACL injury. A recent study[2] examined the effects of ACL transection (ACLx) in an ovine model. In vivo stifle joint motions were recorded, and recreated in vitro using a novel robotic testing platform. Joint and tissue loads were simultaneously recorded during reproduction of in vivo joint motion[2]. This novel approach was shown to be able to reproduce in vivo motions within less than 0.1° and 0.1mm[2].   The main objective of the present study was to determine if in vivo ligament forces, obtained using the principle of superposition, pass through respective ligament insertional footprints. This study evaluated the accuracy of the measured ligament forces, as they should pass through their bony insertions. This accuracy was examined for medial and lateral collateral ligaments (MCL and LCL), and posterior cruciate ligament (PCL) in ACLx sheep.   METHODS Stifle joints from N=4 sheep that had been previously examined in ACLx kinematics studies were digitized using a coordinate measuring machine. The ligament insertional areas were thoroughly recreated in 3D space, along with the spatial position of the kinematic measurement device. Anatomic coordinate systems were defined on the femur and the tibia. These data were then exported to MATLAB scripts for further analysis. The ligament insertional areas were approximated as planes using least squares regression technique. The intersection of the ligament force vectors with the plane approximations were then calculated. The direction of a ligament force was deemed accurate if the distance between the calculated intersection and footprint centroid was within a determined threshold. A preliminary threshold was calculated as the maximum distance between the centroid and measured points of the footprint. RESULTS Analysis of the data indicated that the technique increases in accuracy for high ligament loads (Figure 1). That is to say as the ligament loads increase, the intersection-centroid distance is reduced. For lower ligament loads (mainly within the “toe” region of the ligament force-displacement behavior), however, the method requires further refinement. DISCUSSION AND CONCLUSIONS This study indicated that the method requires further refinement based on the limitations induced currently. Preliminary data shows that accuracy increases as ligament load magnitudes increase as well. Finding the intersections on plane approximations of the insertional footprints can lead to very large error when the planes approach a parallel state. In these states, a small angular change in force direction can cause a very large change in intersection-centroid distance. Each ligament and its insertions have different functions and geometries, and as such require separate limitations. Future studies would require modifications to the analysis method to account for the limitations involved with the current method

Stress-Induced Hyperglycemia in General Surgery: a Narrative-Review

Background: Stress-induced hyperglycemia, also known as stress hyperglycemia, occurs after severe stress on the body, such as surgery. Awareness of this condition and its management are essential to reducing complications and mortality in patients after general surgery. This study aimed to review studies conducted on stress hyperglycemia in patients who underwent general surgery. Materials and Methods: This review study investigated the outcomes and management of stress hyperglycemia in general surgery patients. From 2014 to 2024, the keywords “stress hyperglycemia” and “general surgery” were searched in the PUBMED, ELSEVIER, and CENTRAL databases. Results: The incidence of stress hyperglycemia varies between studies but often occurs in more than 20% of patients. Compared with diabetic patients undergoing general surgery, patients with stress hyperglycemia have more severe rates of complications and mortality. Complications of stress hyperglycemia include infection, necrosis, organ damage, and mortality. Stress hyperglycemia can also increase the length of hospital stay. Conclusion: The results of this study showed that stress hyperglycemia was common in people who had general surgery and was linked to a higher risk of complications and death compared to patients who did not have hyperglycemia or diabetes

Review of the Effects of Vitamin C on Wound Healing

Background: The healing process is one of the main issues for the medical and general population. Studies have shown that vitamin C can accelerate this process, in this study, we aimed to review the effects of vitamin C on wound healing. Methods: We searched PubMed, MEDLINE, and Elsevier databases for studies with the keywords “vitamin C” OR “ascorbic acid” AND “wound healing” OR “wound repair.” Studies from the start of 2013 to the end of 2023 were reviewed. Results: Few studies have evaluated the effects of Vitamin C on wound healing. Six studies were assessed, which found that vitamin C significantly improves wound healing, closure, post-healing appearance, decreased bacterial load, and inflammatory markers. Conclusion: Given that only a few studies have confirmed the effects of Vitamin C on wound healing, further studies are required to appropriately confirm the association

LONG TERM IN VIVO KINEMATICS OF THE OVINE STIFLE JOINT FOLLOWING ANTERIOR CRUCIATE LIGAMENT TRANSECTION

INTRODUCTION Osteoarthritis (OA) is a degenerative joint disease involving the breakdown of articular cartilage, which is common after injury or with aging1. Following knee injury, sheep develop OA at a slightly accelerated rate compared to humans but with some similar patterns2. In an ovine knee injury model3,4, altered gait mechanics and degradation of the cartilage has been observed 20 weeks post anterior cruciate ligament (ACL) transection (Tx) surgery; however, potential alterations in gait at 40 weeks post ACL Tx surgery remain to be determined. Therefore, the objective of this study was to investigate the in vivo kinematics of the ovine stifle joint over time (20 weeks and 40 weeks) following ACL Tx. METHODS Force Plate Testing. Three skeletally mature 3 to 4-year-old female Suffolk-cross sheep (average weight 77.1kg) were led across an embedded force platform (Kistler Instrumente, Winterthur, Switzerland) until 20 hind limb hoof strikes were recorded at 1200 Hz. Peak hind limb vertical ground reaction force was determined prior to surgical plate implantation, and then serially prior to each kinematic data collection. Surgical Procedure. All sheep had a bone plate implanted onto each of the proximomedial aspect of the tibia and the distolateral aspect of the femur of their right hind limb, four weeks prior to kinematic testing. Kinematic Collection and Bone Digitization. On the day of kinematic testing, a stainless steel post was attached to each plate and an instrumented spatial linkage (ISL) mounted between them. The ISL consisted of six rotational encoders providing a measurement of position and orientation in six degrees of freedom (6-DOF) to its motion throughout gait. The in vivo kinematics of the stifle joint were measured while the sheep walked on a treadmill at 2 mph (0.89 m/s). Each sheep then underwent arthroscopic ACL Tx surgery on their right hind limb. The in vivo gait kinematics were measured again over time at 20 and 40 weeks post ACL Tx. Following kinematic testing at 40 weeks, the animals were euthanized. A coordinate measuring machine was used to measure anatomic landmarks on the bone with respect to the ISL in order to create an anatomically relevant coordinate system. Analysis. Data are presented as mean ± SD. RESULTS Figure 1: The 6-DOF in vivo gait kinematics of the ovine stifle joint, intact (black), 22 weeks post ACL Tx (red), and 40 weeks post ACL Tx (blue). DISCUSSION AND CONCLUSIONS These data indicate that the in vivo kinematics of the ovine stifle joint do change over time following ACL Tx. The kinematic changes appear to be more drastic after 22 weeks, and do not entirely return back to pre-injury mechanics in all rotations and translations after 40 weeks. As shown in Figure 1, the medial-lateral as well as posterior-anterior translation of the joint is progressively altered post ACL Tx over time. Rotationally, the internal-external kinematic curve at 22 weeks is dissimilar to the intact motion, however by 40 weeks a recovery towards the intact measurement is seen as the animal compensates for the injury. In the future, principal component analysis will be utilized to compare these gait changes. In conclusion, the transection of the ACL causes long-term changes in the in vivo kinematics of the joint. Alterations of the kinematics may result in degradation of cartilage due to abnormal loading of the joint and overall damage in the joint due to compensation of the instability post ACL Tx, which is a painful and destructive condition

Effect of Low-level Laser Therapy on Bone Defect Repair in Diabetic and Osteoporotic Rats using the Real-Time PCR Technique

Introduction: Bone formation is disturbed in type 1 diabetes followed by changes in the bone microstructure. The most important metabolic disorder in diabetes is osteoporosis, which is characterized by bone loss and bone structure degradation. This study aimed to determine the effect of lowpower laser on bone defect repair in the experimental model of diabetes and osteoporosis. Materials & Methods: A total of 30 fourmonth-old female Wistar rats weighing 190-220 g were selected and randomly divided into six groups, including 1: non-diabetic control (Co.), 2: non-diabetic laser (L.), 3: diabetic control (Co.D.), 4: diabetic laser (L.D.), 5: diabetic alendronate (A.D.), and 6: diabetic laser + alendronate (L.A.D.).Diabetes was induced in groups 3, 4, 5, and 6. All groups underwent ovariectomy and partial bone defect. In the laser group, a lowlevel laser (890nm, 80 Hz, 1/5J / cm 2) was radiated to 3 points at the defect location. Tibia bones were collected, and Real-time PCR was performed after a month. The data were analyzed using ANOVA. A p-value less than P<0.05 was considered statistically significant. Ethics code: 13237-91-1-1393- 10397 Findings: The t-test showed a significant decrease in tibia bone density in diabetic and osteoporotic rats, compared to the nondiabetic control group. Moreover, analysis of gene expression data (ANOVA, P<0.05) revealed a significant difference between the group of diabetic laser + alendronate and other groups in terms of Runx2 gene expression and Osteocalcin. Discussions & Conclusions: According to the findings, laser therapy combined with alendronate can accelerate the repair of partial bone defect in the experimental model of diabetes and osteoporosis. Keywords: Low-level laser, Osteoporosis, Partial bone defect, Real-time PCR, Type 1 diabete

Prenatal Diagnosis of Leukocyte Adhesion Deficiency Type-1 (Five Cases from Iran with Two New Mutations)

Leukocyte adhesion deficiency type-1(LAD-1) is one of the autosomal recessive immunodeficiency diseases that results from mutation in integrin beta 2 (ITGB2) gene. The aim of this study was to investigate molecular prenatal diagnosis of LAD-1. Four pregnant women with five fetuses (one twin fetus) with clinical and laboratory diagnosis of LAD-1 in their previous children were studied. The chorionic villus sampling (CVS) was obtained when mothers were in 10-12th weeks of gestation. Mutation analysis of ITGB2 gene for affected children revealed 3 misssense mutations (c.382G>A,   a   novel   mutation,   c.2146G>C,   and   c.715G>A)   and   one   splice  site novel mutation (c.1877+2T>C). All parents were heterozygous for these mutations. Consideration of affected gene regions for five CVS samples showed two homozygotes and one heterozygote for mutant allele and two homozygotes for normal allele. Interestingly, one  of  the  twin  fetuses  was  affected  and  another  was  normal.  Briefly, two  cases  of CVS samples were affected and three cases of remained CVS samples were unaffected. This is the first report of prenatal diagnosis of LAD-1 from Iran with two new mutations that can be used for genetic and prenatal diagnosis for all patients suspected to LAD1 and can be helpful to prevent the birth of affected children with LAD-1. This  abstract  was presented  in  the  Second  International  Congress  of  Immunology, Asthma and Allergy, Tehran, Iran 2013