novel phantom design for brachytherapy quality assurance

Background: One major challenge in brachytherapy is to verify the accuracy of dose distributions calculated by the treatment planning system. In this project, a new phantom design has been introduced for quality assurance of dose distributions in gynocological [GYN] brachytherapy implants using EBT GafChromic film. Materials and Methods: This phantom has been designed and fabricated from 90 slabs of 18×16×0.2 cm[3] Perspex to accommodate a tandem and ovoids assembly, which is normally used for GYN brachytherapy treatment. In addition, this phantom design is allowing the use EBT GafChromic films for dosimetric verification of GYN implants with Cs-137 Selectron LDR system. With this assembly, GafChromic films were exposed using a plan designed to deliver 2.5 Gy dose to point "A" in Manchester system for tandem and ovoids configurations and to deliver 1.5 Gy of dose to 0.5 cm distance from the lateral surface of ovoids for using ovoid-pair. The measured dose distributions with GafChromic films were compared with the TPS isodose lines both numerically and spatially. For a quantitative analysis of the results, the measured doses values at several points of interest were evaluated with the treatment planning data and values obtained following the TG-43 dose calculation formalism. Results: The results of these investigations have indicated that the new phantom design enables us to measure differences of greater than +/-6% for LDR brachytherapy GYN treatments. Conclusion: The new phantom design could be utilized for the QA procedure of the brachytherapy remote after loading systems to confirm the accuracy of dose distribution in GYN implants

[Histologic and histomorphometric changes of testis following oral exposure to methyl tertiary-butyl ether in adult rat]

Methyl tertiary-butyl ether [MTBE] is used to reduce carbon monoxide and ozone in urban air and to boost fuel octane. There is a lack of knowledge in the literature about the histomorphometric changes of the testis following exposure to MTBE. Therefore, this experimental study was performed to determine the effect of oral exposure to MTBE on histologic and histomorphometric changes of testis in adult rat. A total of 25 adult male Sprague-Dawley rats were randomly divided into five equal experimental groups: control, almond oil and three treatment groups which received 400, 800 and 1600 mg/kg/day MTBE in almond oil by gavages for 30 consecutive days. Histomorphometric analysis showed no significant difference in absolute and relative testis weight, connective tissue thickness, germinal epithelium height, tunica albuginea thickness and Sertoli cell numbers between experimental groups [P>0.05]. However, trend analysis showed that the seminiferous tubule diameter increased and interstitial cell numbers as well as spermatocyte and spermatid cell numbers decreased significantly in MTBE treated groups [P<0.05]. It may be concluded that MTBE could exert adverse effects on spermatogenic cells in adult rat. Whether the observed changes in the present study are due to the direct effect of MTBE via passing blood-testis barrier or its indirect effect through another mechanism should be elucidated in future studies.

Lessons learnt from errors in radiotherapy centers

The purpose of this work is to discover and analyze errors and incidents in some radiotherapy centers, and to introduce methods that could reduce their occurrences, especially those which had happened due to the use of improper and inadequate equipment. This work is a first step toward clarifying the role of education in a risk-conscious culture, and changing the attitude of radiotherapy staff when they are working under encouraging conditions that remove barriers for reporting errors. For the present study clinical investigation, the data of 6000 patients were checked. They were treated at a few radiotherapy centers during one year. Patients were treated by linear accelerator or cobalt machine, photon or electron beams. A purposely designed check list was used for error data collection. Incidents were discovered by manual check at different steps of treatment. By highlighting frequency of occurrence, further investigation for preventing error repetition can be possible. Eighty five incidents were reported by Technologists, fifty four were reported by Physicists, and twenty six events were pointed out by Radiation Oncologists. About fifty percent of total 165 detected events were classified as treatment field errors. Geometrical misses in treatment field have the highest probability for both photon and electron beams. Incident prevention considering likelihood of individual event can be possible when using facilities like record-and-verification [R and V] system and electronic-portal-image-device [EPID], taking seriously QA, defining and implementing layers of defense in depth, and making an organized system for reporting and analyzing errors

[Approaches to learning among nursing and midwifery students' of Bushehr university of medical science in 2012-2013]

Introduction: Learning Approaches are among effective factors in students' learning that play an important role in educational performance and achievement. Understanding how students' learning approaches change over time is important since one of the main purposes of higher education is to enable students to develop advanced learning as they progress through their studies. The aim of this study was to determine learning approaches of nursing and midwifery students of Bushehr University of Medical Sciences in 2012-13

Method: This was a descriptive-analytic study conducted in a cross-sectional method in 2012-13. Learning approaches of nursing and midwifery students of Bushehr University of Medical Sciences were evaluated by means of revised two factor version of the Study Process Questionnaire. We used census for data collection, then the data entered into SPSS ver. 18 and analyzed using descriptive and analytic statistics

Results: Students use deep learning approach more than surface learning approach; however, Kruskal-Wallis test didn't show a significant differences in surface and deep learning approaches of students in different courses [P=0.165, P=0.449] and years of study [P=0.357, P=0.768]. Mann-Whitney test showed a significant difference in surface learning of deferent genders [P<0.001]

Conclusion: Majority of students uses deep approach; however in higher years of education, there was no change in the students' approaches. In higher education there was a great emphasize on developing deep learning. Therefore a deep assessment is required to be conducted on educational programmers and faculty members

En-bloc transplantation: an eligible technique for unilateral dual kidney transplantation

Kidney transplantation is the best available treatment for patients with end-stage renal disease. To evaluate the en bloc anastomosis technique for unilateral dual kidney transplantation [DKT]. From May to October 2011, 5 patients [4 women and 1 man] with mean age of 31.8 years underwent unilateral DKT with this technique in which distal end of the aorta and proximal end of inferior vena cava [IVC] were closed with running sutures. Then, proximal end of the aorta and distal end of the IVC were anastomosed to internal [or external] iliac artery and external iliac vein, respectively. Post-operative course was uneventful. No vascular and urologic complications developed; all patient had acceptable serum creatinine at discharge time and up of 2-6 months of post-operation follow up. Unilateral DKT is a safe method for performing DKT. The proposed en bloc anastomosis can improve the outcome of the graft by reducing the cold ischemia and the operation time

investigation on the effects of the Aloe Vera extract on the thickness of the retina in male diabetic rats

Retina is a part of the central nervous system derived from the neuroectoderm and made up of 5 layers. In this study, the changes in the thickness of the retinal layers as a consequence of diabetes and effect of Aloe Vera gel extract in male rats were assessed. Thirty Sprague Dawley adult male rats [175 +/- 25 g] in two age groups [4 and 8 weeks] were divided into 6 groups of 5 as control, diabetic and diabetic receiving 400 mg/kg Aloe Vera extract. Diabetes was induced by IP injection of 50 mg/kg of STZ [streptozotocin]. The animals were weighed and their blood sugar was measured by glucometer before STZ administration and 24 h thereafter. Animals were anesthetized with sodium thiopental [40 mg/kg] via IP injection. After removal of eyes on both sides, retina was dissected out precisely and fixed in 4% glutaraldehyde, post fixed in osmium tetroxid 1%, dehydrated and then embedded in TAAB resin. Thin sections [1 ?m] were stained with toluidine blue stain and viewed under light microscope. Ten slides were prepared from each animal. The results revealed reduction of the blood glucose levels and body weight in treated rats in comparison to diabetic groups. The thickness of neural retina and its layers were different as well. In the group treated with Aloe Vera the thickness of retina and its layers retained their normal histologic structures

Liver transplantation in the presence of old portal vein thrombosis

Portal vein thrombosis [PVT] has been mentioned as a potential obstacle to liver transplantation [LTx]. To review the impact of PVT on orthotopic liver transplant [OLT] outcome. Between January 2006 and April 2009, 440 OLT were performed in Shiraz Transplant Unit of whom, 35 [7.9%] cases had old PVT with recanalization. Data were retrospectively collected regarding the demograph- ics, indication for OLT, Child-Turgot-Pugh classification, pre-transplant diagnosis of PVT, perioperative course and managements, relapse of PVT, early post-operative mortality and morbidity. All patients received liver from deceased donors, underwent thrombendvenectomy with end-to-end anastomosis without interposition graft and evaluated daily for 5 days and thereafter, biweekly by duplex sonography during the follow-up period for 2 months. They were treated by therapeutic doses of heparin followed by warfarin to maintain an INR of 2-2.5. The causes of end-stage liver disease were hepatitis B in 11, cryptogenic cirrhosis in 11, primary scle- rosing cholangitis in 5 and other causes in 8 recipients. Extension of thrombosis was through confluence of superior mesenteric and splenic vein in 32 and to superior mesenteric vein in 3 patients. The mean +/- SD op- eration time was 7.2 +/- 1.5 hrs. The mean +/- SD transfusion requirement was 5.4 +/- 2.8 units of packed cells. The mean +/- SD duration of hospital stay in these patients was 17.7 +/- 10.9 days. Eight patients died; 1 developed early in-hospital PVT, 1 had hepatic vein thrombosis, and 1 died of in-hospital ischemic cerebrovascular ac- cident, despite a full anticoagulant therapy. The mean +/- SD follow-up period for those 28 patients discharged from hospital was 16.6 +/- 7.9 months; none of them developed relapse of PVT. The overall mortality and mor- bidity was 28% and 32%, respectively. There was no relapse of PVT in the other patients. The presence of PVT at the time of OLT is not a contraindication for the operation but those with PVT have a more difficult surgery, develop more postoperative complications, and experience a higher in-hospital mortality

Outcome and characteristics of patients on the liver transplant waiting list: Shiraz experience

The only curative therapy for end-stage liver disease is transplantation but due to a shortage of available donor livers the waiting list mortality is high. This study aimed to evaluate the outcome and characteristics of patients on the waiting list for liver transplantation in Shiraz, southern Iran during the period from April 2004 to March 2007. Medical records of all chronic liver disease patients >/= 14 years that were on the waiting list for liver transplantation at the Nemazee Hospital Organ Transplant Center during April 2004 to March 2007 were reviewed. Hospital records were used to retrieve demographic, clinical and laboratory data. Records of the referring gastroenterologists provided information about the etiology and complications of liver disease. The patients were followed at the end of the study period by clinic visits or telephone contact. There were 646 patients on the waiting list for liver transplant during April 2004 to March 2007. Hepatitis B was the most common etiology of liver disease [31.2%]. Of those on the waiting list, 144 patients 22.3%] underwent liver transplant and 166 [25.7%] died while waiting for a transplant. The mean waiting period for transplant was 6.6 months. Receiving a transplant was correlated with the etiology of liver disease and Rh blood group [p<0.05] but had no significant association with gender or ABO blood type. Among non-transplanted patients, survival was lower in those who had a history of encephalopathy, SBP or uncontrolled ascites and in patients with a Child-Turcotte-Puph [CTP] class C and/or a Model of End-stage Liver Disease [MELD] score >/= 15. Hepatitis B virus is the most common cause of end-stage chronic liver disease amongst patients on the waiting list for liver transplant in Shiraz, southern Iran. Patients with a MELD score >/= 15 particularly those with a history of SBP, hepatic encephalopathy or uncontrolled ascites are recommended for waiting list enrollment

transitional zone of the renal artery in cats

The length and structure of the transitional zone in the tunica media in the renal artery of adult male cats were investigated. In addition, the volume of the lumen and different layers in transitional and non-transitional zones in the right and left sides were also determined. Morphometrical, histological and stereological studies were performed on 16 renal arteries of 8 adult male cats. After perfusion and morphometrical measurement, routine tissue processing was carried out by autotechnicon. The processed tissues were embedded in paraffin and sectioned serially into 5 micro m thickness. The sections were stained with haematoxylin and eosin and orcein. In the morphometrical measurement, the right renal arteries were longer than the left ones with a mean value of 22.0 +/- 0.2 and 18.8 +/- 0.1 mm, respectively. Despite the fact that the right renal artery is commonly longer, the length of transitional zone was 7mm in both renal arteries of adult male cats. The artery has a structure between muscular and elastic type at its origin with several elastic layers in the tunica media which is gradually changed to a muscular type at the distal section after 7 mm from origin of aorta. Transitional zone has an arrangement of parallel elastic fibers which become rare and fragmented towards the non-transitional zone. The volume of tunica intima, tunica media, tunica adventitia and lumen of the artery decrease from transitional zone towards the non-transitional zone and the volume of these areas in both transitional and non-transitional zones in the right renal artery is more than the left one. The volume of the lumen in transitional zone differs significantly compared to non-transitional zone, in both sides [P<0.05]. Also there is a significant difference in the volume of the lumen in non-transitional zone between right and left renal arteries [P<0.05]

[Histomorphological and histomorphometrical study of embryonic renal artery in Mehraban ewes]

To study microscopic structure of renal artery and measurement of histomorphometrical parameters before birth. Observational study. Twelve embryonic artery of both sexes at 3 and 4 months age. Samples of arteries were taken and fixed in 10% formalin. The process was done in autotechnicon. Sections of 6 micron were stained by H and E and green mason trichrom and studied under light microscope. Descriptive statistics. All 3 layers of the wall of vessels were well developed in both sexes and ages of renal artery. In both ages, hitomorphometrical studies showed that total diameter of renal artery in males was lesser than the females. Increase in age increased thickness of wall and diameter of lumen. While there were not significant difference between sexes, the measured parameters of renal artery showed significant difference between age groups. Histomorphological structures of embryonic renal artery in sheep showed 3 vascular layers. Internal elastic membrane was clearly and external elastic membrane was poorly observed and in some regions was interrupted. The recent layer will completely develop after birth by development of blood circulation. Increase in the age increase percentage of tunica media. On the other hand, percentage of other layers showed partially decrease

Comparison of optic lens proteins among animals at different stages of development

The purpose of this investigation was to study and compare the electrophoretic patterns of optic lens proteins of different species of domestic animals at pre- and post-natal ages. Optic lenses were removed from the embryo or adult sheep, cattle, goat, camel and chicken at the slaughter-house then homogenized and subjected to sodium dodecylsulfate polyacrylamide gel electrophoresis [SDS-PAGE]. In all animals, except chicken, majority of proteins had molecular weights of less than 33 kDa and their concentrations were not affected by the age of animals at pre- or post-natal stages. A 9 kDa protein which was present in adult sheep optic lens was absent in sheep fetal lenses at different age groups. Prominent differences were observed in camel and chicken. In camel, proteins with molecular weights of 30 and 38 kDa were present, the concentration of which was much lower in other animals. A protein of 57 kDa which constituted the major protein of chicken optic lens was absent in other species of animals. The concentration of proteins in the range of 25-30 kDa increased with the age of chicken embryos. These proteins were remarkably different from those of adult chicken lens proteins except the 57 kDa protein which was also the predominant protein in the embryo. The 38 kDa protein disappeared and a 20 kDa protein appeared in the chicken embryo lens as compared with adult chicken lens. These data indicate extensive differences in the lens proteins of animals and suggest different physiological functions of lens proteins in different animals at different stages of development

Histomorphometrical syudy of pancreas in Mehraban female sheep

In the present study, pancreas glands in Mehraban breed of female sheep were histomorphometrically studied in four different age groups included: fetus, newborn, sexually mature and old ages. The results of histomorphometrical analysis with regard to frequency and percentage of parenchymal and stromal structures such as, exocrine secretory units, secretory ducts, blood vessels, islets of Langerhans and stromal connective tissue showed that minimum and maximum percentages of structures within the whole gland belonged in fetal stage, to blood vessels and stromal connective tissue; newborn stage, to blood vessels and exocrine secretory units; in sexually mature, to islets of Langerhans and exocrine secretory units and in old stage, also to islets of Langerhans and exocrine secretoiy units, respectively. The diameter changes of islets of Langerhans in different age groups from minimum to maximum were included: fetus, old, sexually mature and newborn stages. In comparison between different age groups, the frequency of exocrine secretory units showed a significant increase from fetal stage to newborn, sexually mature and old stages [P<0.05]. On the other hand, there was a significant decrease in frequency of secretory ducts from fetal stage to newborn, sexually mature and old stages and there was also a significant decrease in frequency of blood vessels from fetal to newborn stage [P<0.05]. Significant decrease was also observed in frequency of islets of Langerhans from fetal and newborn stages to sexually mature and old stages. In comparison between groups, there was a significant increase in diameter of islets of Langerhans from fetal to newborn and sexually mature stages and decrease from newborn to sexually mature and old stages Our study revealed that, there was no significant difference in parenchymal and strotmal structures and diameter of islets of Langerhans between different parts of the gland in each age group. However, the above mentioned parameters often showed significant differences between different age groups. These differences were more prominent between fetal stage compared to the other age groups. Therefore, it can be concluded that structural changes of parenchyma and stroma of pancreas gland begin from prenatal period and will proportionally continue during the period of post-natal development

[Effects of obesity on prolonged thiopental surgical anesthesia: Iranian fat tailed type sheep used a new model]

Anesthesiologist in human medicine noticed that patients with higher defree of fat deposit need more anesthetics and also recovery period in these patients is longer than normal patients. These indicate the important role of fat deposit that may play in prolonged thiopental anesthesia. Unfortunately, due to lack of clinical model, to the best of our knowledge, no experimental studies has been yet designed to prove the experience that anesthesiologist have obtained during clinical practice. Consequently, we thought that the Iranian fat tailed type sheep could be the best model to be used; since this kind of sheep could deposit a large amount of fat up to 10% of its body weight or more, depending on strain and age, at its tail area. Prolonged surgical anesthesia was induced in Iranian fat tailed type sheep with initial dose of 26.51 +/- 5.82 mg/kg of body weight, and maintained successfully by repeatedly injecting the maintenance dose of 22.97 +/- 5.26 mg/kg, 20.31 +/- 5.67 mg/kg and 14,10 +/- 5.31 mg/kg of thiopental for 1st., 2nd. and 3rd. hour of anesthesia respectively in this study. Maintenance dose in tail amputed animal is decreased respectively from normal sheep 22,97 +/- 5.26 to 21.99+6.34, 20.31 +/- 5.67 to 14.75+4,61 and 14.10 +/- 5,31 to 8.56 +/- 3.20 mg/kg during 1st., 2nd. and 3rd. hour of anesthesia. The differences between maintenance dose in normal and amputated tail sheep in 2nd. and 3rd hour of anesthesia could be attributed to fat removal in amputated tail sheep. Average recovery time in normal animals was 358.10 +/- 65.77 minutes. But, recovery time in tail amputed animal significantly decreased from 358.10 +/- 65.77 to 204.50+88.49 minutes. The differences could be due to higher metabolism and excretion rate in amputated tail sheep; since, there is higher plasma concentration of thiopentail in this group of sheep, due to lack of high fat tissue, consequently, the drug gets metabolized and excreted faster and recovery period becomes shorter. Results obtained in this study could firmly prove the important role of obesity in human and veterinary anesthesia. These data also suggest that anesthesiologist should more seriously consider the obesity at the time of practice. All this experiment proves that sheep is a good model in this kind of research