On-line set-up corrections during radiotherapy of patients with gynecologic tumors

PURPOSE: Positioning of patients with gynecologic tumors for radiotherapy has proven to be relatively inaccurate. To improve the accuracy and reduce the margins from clinical target volume (CTV) to planning target volume (PTV), on-line set-up corrections were investigated. METHODS AND MATERIALS: Anterior-posterior portal images of 14 patients were acquired using the first six monitor units (MU) of each irradiation fraction. The set-up deviation was established by matching three user-defined landmarks in portal and simulator image. If the two-dimensional deviation exceeded 4 mm, the table position was corrected. A second portal image was acquired using 30 MU of the remaining dose. This image was analyzed off-line using a semiautomatic contour match to obtain the final set-up accuracy. To verify the landmark match accuracy, the contour match was retrospectively performed on the six MU images as well. RESULTS: The standard deviation (SD) of the distribution of systematic set-up deviations after correction was < 1 mm in left-right and cranio-caudal directions. The average random deviation was < 2 mm in these directions (1 SD). Before correction, all standard deviations were 2 to 3 mm. The landmark match procedure was sufficiently accurate and added on average 3 min to the treatment time. The application of on-line corrections justifies a CTV-to-PTV margin reduction to about 5 mm. CONCLUSIONS: On-line set-up corrections significantly improve the positioning accuracy. The procedure increases treatment time but might be used effectively in combination with off-line corrections.     

The evaluation of myocardial damage in 83 young adults with carbon monoxide poisoning in the East Anatolia region in Turkey

Carbon monoxide (CO) poisoning is the leading cause of death from intoxication. In CO poisoning, it is important to know if there are any symptoms regarding myocardial damage, which are usually unobserved as a result of hypoxia. This study was planned to assess myocardial damage in young healthy patients with CO poisoning. Eighty-three young healthy cases who had been exposed to CO were included in this study. The demographic and clinical characteristics, the origin of CO gas and smoking habits of the patients were recorded. The evaluation of ECG, peripheral ABG, complete blood count and serial cardiac biomarkers (creatine kinase, creatine kinase-myocardial band and troponin I) measurements were performed in all cases. Additionally, echocardiogram (ECHO) and myocardial perfusion single-photon emission computed tomography (SPECT) were performed at the appropriate times in all cases. The mean age of the patients was 27.3 +/- 10.9 years. The main complaint of the patients was loss of consciousness with a 62.7% rate. The average carboxyhaemoglobin level of the patients was 34.4 +/- 15.9%. Sinus tachycardia was present in 26.5% of patients. Diagnostic ischaemic ECG changes were present in 14.4% of patients. In myocardial SPECT, myocardial ischaemic damage was observed in 9 cases, in 6 of whom ECHO findings were also confirmed. Myocardial damage due to CO poisoning should not be ignored. If patients are at risk in terms of myocardial damage, further studies, such as ECHO and scintigraphy are needed to determine myocardial damage resulting from CO poisoning. However, in the young adults of the risk group, if the baseline ECG and serial cardiac biomarkers are normal, further studies such as ECHO and scintigraphy, considering the length of exposure and the severity of poisoning, may not be necessary for the evaluation of myocardial damage due to CO poisoning.     

The effects of vigabatrin on rat liver antioxidant status

The anti-epileptic drug vigabatrin was developed as an inhibitor of gamma-aminobutyric acid transaminase, and its ability to increase inhibition in the central nervous system led to its testing in an animal model. In animal models chronic use of vigabatrin is associated with irreversible myelin vacuolation. Antioxidant drugs change the antioxidant capacity of the body. Oxidative stress of the body increased when valproic acid and carbamazepine were used chronically. To assess whether vigabatrin may affect protein oxidation and lipid peroxidation, glutathione, glutathione peroxidase (GPx), and glutathione-S-transferase (GST) levels were studied in the livers of 57 rat fetuses after administration of vigabatrin to the mothers (19 in the first week of pregnancy, 20 in the second week, and 18 in the third week) and in 19 control rat fetuses without vigabatrin. We compared the results of administration of vigabatrin in each group with the controls. Rat fetus protein oxidation in group I (0.686 nmol/mg protein) and group II (0.723 nmol/mg protein) was higher than in the control group (0.388 nmol/mg protein). Lipid peroxidation (0.209, 0.224, 0.253 nmol/mg protein, respectively) and GPx levels (345.4, 329.0, 283.2 nmol/mg protein, respectively) of groups I, II, and III were higher than in the control group (0.104, 167.2 nmol/mg protein, respectively). GST in group II (79.2 nmol/mg protein) and group III (77.8 nmol/mg protein) were not different from that in the control group (78 nmol/mg protein). It was found that vigabatrin affected all the parameters that were studied, especially in group I, which was given the drug in the first week of pregnancy.     

Supernumerary fourth and fifth molars: a report of two cases

Panoramic radiographs of two female patients ages 22 and 21 revealed the presence of two impacted bilateral upper fourth molars and unilateral (right) upper fourth and fifth molars. All of the teeth were distomolars. The supernumerary teeth had normal tooth morphology with regard to their crowns and roots but were slightly smaller than the existing third molars. Their crowns were either two or three tuberculated and they all had single roots.     

Utility of Tc-99m human polyclonal immunoglobulin G scintigraphy for assessing the efficacy of yttrium-90 silicate therapy in rheumatoid knee synovitis

PURPOSE: The aim of this study was to determine the utility of Tc-99m human polyclonal immunoglobulin G (HIG) scintigraphy for evaluating the efficacy of yttrium-90 (Y-90) silicate therapy in rheumatoid knee synovitis. MATERIALS AND METHODS: Fifteen patients (13 women, 2 men; mean age, 53.5 +/- 8.4 years) with rheumatoid arthritis had radionuclide synovectomy using 185 MBq (5 mCi) Y-90 silicate to evaluate 24 knee joints with chronic persistent synovitis. Radiologic and clinical evaluations and Tc-99m HIG scans were performed in each patient before radionuclide synovectomy. Each patient was reassessed 3, 6, 9, and 12 months after therapy using clinical examination and Tc-99m HIG scintigraphy. RESULTS: In 14 of 24 knee joints (4 Larsen stage I, 10 Larsen stage II) that had excellent or good clinical responses to Y-90 silicate therapy, the Tc-99m HIG index values 3 months after treatment were significantly lower than the pretreatment index values (P < 0.001). In 13 of these 14 joints, these low index values and clinical results remained constant throughout the 1 year of follow-up. One patient (1 of the 14 knee joints) experienced severe pain and swelling as a result of recurrent arthritis at 9 months, and the Tc-99m HIG index value increased at 9 months and remained high 12 months after therapy. In 10 of 24 knee joints (4 Larsen stage II, 6 Larsen stage III) that had a fair or poor clinical response, Tc-99m HIG index values were statistically similar before and after radionuclide therapy. CONCLUSIONS: Quantitative Tc-99m HIG scintigraphy is a valuable method for assessing the efficacy of Y-90 silicate therapy in rheumatoid knee synovitis.     

Iron supplementation in experimental hyperthyroidism: effects on oxidative stress in skeletal muscle tissue

This study was designed to investigate the effects of iron supplementation on the parameters of oxidative stress in the skeletal muscle tissue of hyperthyroidism induced rats. Hyperthyroidism was found to cause an increase in thiobarbituric acid-reactive substances (TBARS) and copper zinc superoxide dismutase (Cu, Zn SOD) activity, but decreases in the glutathione-peroxidase (GSH Px) activity and glutathione (GSH). Iron supplementation caused an increase in TBARS and a decrease in GSH. Iron supplementation in hyperthyroid rats attenuated the hyperthyroid state, but lowered the plasma ferritin level, which is considered an indicator of thyroid hormone action. Iron supplementation caused no additional increase in the TBARS in hyperthyroid rats, ameliorated the decrease in GSH content and abolished the induction of Cu, Zn SOD. Our findings suggested no increase, but a decrease, in the risk of oxidative stress in iron supplemented hyperthyroid rats. Whether supplementation of iron would have similar effects in humans should be further investigated in clinical studies.     

The impact of propylthiouracil therapy on lipid peroxidation and antioxidant status parameters in hyperthyroid patients

This study was performed on 17 hyperthyroid patients and 15 healthy controls. The patients were under propylthiouracil (PTU) therapy at a dosage of 3 x 100 mg/day for one month. Blood samples, taken at the beginning and on the 30th day of therapy, were analyzed for hormonal parameters (T3, T4, TSH), lipid peroxidation endproduct [thiobarbituric acid reactive substances (TBARS)] and antioxidant status parameters: glutathione (GSH), glutathione peroxidase (GSH-Px) and CuZn superoxide dismutase (CuZn SOD). Hyperthyroid patients were observed to have significantly higher TBARS, GSH and CuZn SOD levels than controls (P < 0.05, P < 0.001, P < 0.001, respectively). PTU therapy caused a relief in oxidative stress as reflected by significantly decreased TBARS levels (P < 0.001) and a selective modification in the antioxidant status parameters: significant decreases in GSH and CuZn SOD levels (P < 0.001) and a significant increase in GSH Px (P < 0.01) activity. Our findings suggest a selective modification of the antioxidative profile in hyperthyroidism. PTU should also be considered as an in vivo antioxidant, in addition to its antithyroid action.     

Lung perfusion changes in COVID-19 pneumonia: a dual energy computerized tomography study

Objective:There is limited and contradictory information about pulmonary perfusion changes detected with dual energy computed tomography (DECT) in COVID-19 cases. The purpose of this study was to define lung perfusion changes in COVID-19 cases with DECT, as well as to reveal any possible links between perfusion changes and laboratory findings.Methods:Patients who had a positive RT-PCR for SARS-CoV-2 and a contrast-enhanced chest DECT examination were included in the study. The pattern and severity of perfusion deficits were evaluated, as well as the relationships between perfusion deficit severity and laboratory results and CT severity ratings. The paired t-test, Wilcoxon test, and Student’s t-test were used to examine the changes in variables and perfusion deficits. p < 0.05 was regarded as statistically significant.Results:Study population consisted of 40 patients. Mean age was 60.73 ± 14.73 years. All of the patients had perfusion deficits at DECT images. Mean perfusion deficit severity score of the population was 8.45 ± 4.66 (min.-max, 1–19). In 24 patients (60%), perfusion deficits and parenchymal lesions matched completely. In 15 patients (37.5%), there was partial match. D dimer, CRP levels, CT severity score, and perfusion deficit severity score all had a positive correlationConclusions:Perfusion deficits are seen not only in opacification areas but also in parenchyma of normal appearance. The CT severity score, CRP, D-dimer, and SpO2 levels of the patients were determined to be related with perfusion deficit severity.Advances in knowledge:Findings of the current study may confirm the presence of micro-thrombosis in COVID-19 pneumonia.     

Definition and validation of a reference target volume in early stage node-positive cervical carcinoma, based on lymphangiograms and CT-scans.

PURPOSE: To establish a reference planning target volume for postoperative radiotherapy in stage Ib and IIa N+ cervical carcinoma, based on 47 lymphangiograms and 15 CT-scans. METHODS: Radiation oncologists (n=17) from all radiotherapy institutes in The Netherlands were asked to define the clinical target volume (CTV) and planning target volume (PTV), and to delineate (on simulation films) the radiotherapy treatment portals following a radical hysterectomy with lymph node dissection for an early stage cervical carcinoma with positive iliac lymph nodes. A reference PTV was defined by using 47 normal lymphangiograms and CT-data of the pelvis from 15 patients who underwent surgery for cervical carcinoma. The simulation films were digitized and evaluated for adequacy in covering the PTV, previously individually determined by the radiation oncologists. Subsequently, the simulation films were also evaluated for adequacy in covering the reference PTV. RESULTS: Large variations were observed in the portals used and in treatment techniques. From the digitized films, it appeared that in 50% of the cases the defined PTV was not covered adequately. Furthermore, 71% of the treatment plans would not cover the lateral borders of the reference PTV sufficiently. CONCLUSIONS: There appears to be no consensus on the target volumes to be irradiated in postoperative radiotherapy of early stage cervical carcinoma. When a PTV defined on the basis of lymphangiograms and CT-data is taken as a reference, 71% of the treatment plans would not cover this PTV adequately. These findings indicate the need for a consensus in the design of standardized treatment volumes.