Detektory MOSFET jako narzędzie do weryfikowania dawek promieniowania X w radioterapii

SummaryPurposeApplication of MOSFET detectors in photon beam dose measurements in vivo in radiotherapy.Materials and methodsBefore measuring doses in vivo the following parameters such as: the dosimeter response to dose absorption, temperature, gantry angles and field side changes were determined using 6MV and 15MV photon beams. All measurements were made in a phantom to investigate the MOSFET accuracy, in electron equilibrium with a 0.6 cm3 Farmer ionization chamber.ResultsMOSFET parameters are presented in graphs. The conformity between the planned dose and the dose measured in vivo within ±5% was observed in 86% of patients treated with 6MV photon beams and 91% patients treated with 15MV, respectively (SD=3.5%).ConclusionsMOSFET detectors are a useful tool for verifying the planned dose in external photon radiotherapy

MOSFET detectors as a tool for the verification of therapeutic doses of electron beams in radiotherapy

AimTo examine the characteristics of MOSFET (Metal – Oxide Semiconductor Field Effect Transistor) detectors for the purpose of electron beam dose determination in in vivo radiotherapy.Materials/MethodsIndications of MOSFET detectors were recorded from phantom measurements, including: dose values of electron beams, the environmental temperature of the detectors, the incidence direction of an electron beam on the detector, the size of the irradiated field.The change in sensitivity of the detectors when under the effects of accumulated doses was also tested.Because of the very small dimensions of the detectors, they were placed in specially designed aluminium capsules – to ensure electron equilibrium (δ electrons) during the dose measurement. The detector indications were compared to those seen in a Markus type ionization chamber with a calibration certificate. The measurements were made for electron beams with energies of 6, 9, 12, 15, 18 and 21 MeV.ResultsThe following were established experimentally: There is a linear relationship between detector indications and the dose value. A drop in detector sensitivity is associated with increased environmental temperature (as much as 6% as temperatures rise from 22°C to 42°C). There is a non-linear drop in detector sensitivity with accumulated dose. Detector indications are not affected by changes in incident beam angles within the range of –70° to +70°. The dependency of detector indications on the size of the irradiated field conform with those recorded in the ionization chamber, with variations of up to 1.5%. The dependencies and correction coefficients determined in this study allow measurement of electron beam doses with an accuracy of 2.2%.ConclusionsMOSFET detectors are a useful tool for verification of the entrance doses in electron beam radiotherapy

The technique of total body irradiation applied at the leszczyński memorial hospital

PurposeTo improve the reproducibility of patient positioning in fractionated irradiation and to achieve uniform irradiation of the patient, within 12–15Gy, excluding the lungs.MethodTwo special body frames were manufactured, one for treatment planning and the other for the treatment itself. Special tin markers were inserted in the walls to make it possible for a patient to maintain the same position during each fraction of irradiation. Patient treatment was carried out in six fractions (four lateral and two AP/PA fields), twice a day, over three consecutive days. The lungs were shielded during AP/PA fractions and during one lateral fraction. The shape of the shields for AP/PA fields was determined with the use of computer tomography scans, and for lateral fields on the basis of radiographic pictures taken by a simulator. The doses calculated at some selected anatomical points for every patient were checked by in vivo measurements which were carried out by means of MOSFET detectors.Results and conclusionsReproducibility of patient positioning during consecutive treatments and a uniform total dose distribution over the range of 12 – 15 Gy (except in the lungs) have been achieved. This has been confirmed by in vivo measurements

MOSFET detectors as a tool for dose verification in photon beam radiotherapy

CelZastosowanie detektorów typu MOSFET (Metal-Oxide Semiconductor Field Effect Transistor) do pomiaru dawki in vivo w radioterapii.Metody i materiałyWykonano pomiary polegające na zbadaniu zależności wskazań detektorów MOSFET od podanej dawki promieniowania, temperatury ich otoczenia, kierunku padania wiązki promieniowania na detektor oraz od wielkości napromienianego pola – dla wiązek fotonów 6MV i 16 MV. Pomiary zależności wskazań detektorów zostały wykonane w fantomie oraz w powietrzu, w warunkach równowagi elektronowej. W tym celu, ze względu na bardzo małe wymiary detektorów, zaprojektowano nakładki z aluminium, które zapewniały warunki równowagi elektronowej podczas pomiaru dawki. Detektory zostały wykalibrowane z pomocą komory jonizacyjnej typu Farmer 0,6 cm3.WynikiWyniki badań wymienionych wyżej zależności przedstawiono na wykresach. Wykonane, wykalibrowanymi detektorami, pomiary in vivo dawki wejściowej (na głębokości maksymalnej dawki) wykazały zgodność między zaplanowaną i zmierzoną dawką – w granicach tolerancji ±5% – u 86% pacjentów poddanych radioterapii z użyciem wiązki fotonów 6MV i u 91% pacjentów z użyciem wiązki fotonów 15MV (SD=3.5%).WniosekDetektory MOSFET stanowią dobre narzędzie pomiarowe w radioterapii do weryfikowania zaplanowanej dawki promieniowania X wytwarzanego w liniowych przyspieszaczach.PurposeApplication of MOSFET detectors in photon beam dose measurements in vivo in radiotherapy.Materials and methodsBefore measuring doses in vivo the following parameters such as: the dosimeter response to dose absorption, temperature, gantry angles and field side changes were determined using 6MV and 15MV photon beams. All measurements were made in a phantom to investigate the MOSFET accuracy, in electron equilibrium with a 0.6 cm3 Farmer ionization chamber.ResultsMOSFET parameters are presented in graphs. The conformity between the planned dose and the dose measured in vivo within ±5% was observed in 86% of patients treated with 6MV photon beams and 91% patients treated with 15MV, respectively (SD=3.5%).ConclusionsMOSFET detectors are a useful tool for verifying the planned dose in external photon radiotherapy

Role of the cholesterol 7α- hydroxylase and CYP7A1 gene in human physiology and pathology

Cholesterol 7α- hydroxylase (CYP7A1) belongs to the big family of cytochrome p450. Biological significance of cholesterol 7α- hydroxylase is associated with beginning of cholesterol transformation to the bile acids. CYP7A1 affinity to the cholesterol is determined by its unique protein structure, different from the other proteins of cytochrome p450 family. CYP7A1 enzyme is enoded by CYP7A1 gene localized in short arm of chromosome 8. Expression of CYP7A1 gene could be regulated by farnesoid X receptor (FXR) or by kinases, which modulate nuclear receptor`s binding abilities to the gene promoter. Polymorphic variants and mutations present in the promoter region impact on the quality properties of the enzyme. CYP7A1 gene, encoding key enzyme of the cholesterol catabolic pathway is a main candidate to the research of its association with changes of serum lipids levels. Presence of genetic variants can be associated with changed levels of total cholesterol, triglycerides and Low- density lipoproteins (LDL). Promoter polymorphism of CYP7A1 is also main candidate for the research of association with such disease entities as gallbladder stone formation, colon cancer, gallbladder cancer or atherogenic- based diseases.7α- hydroksylaza cholesterolu (CYP7A1) jest enzymem należącym do dużej rodziny cytochromu p450. Znaczenie biologiczne 7α- hydroksylazy cholesterolu związane jest z rozpoczęciem szeregu przemian cholesterolu do kwasów żółciowych. Powinowactwo CYP7A1 do cholesterolu determinowane jest unikalną budową białka, odmienną od reszty białek rodziny cytochromu p450. Enzym ten kodowany jest przez gen CYP7A1, którego locus znajduje się na ramieniu krótkim chromosomu ósmego. Ekspresja tego genu może być regulowana przy udziale farnezylowego receptora X (FXR), bądź zachodzić poprzez szereg kinaz białkowych, modulujących zdolność przyłączania się swoistych receptorów jądrowych do promotora CYP7A1. Warianty polimorficzne i mutacje, występujące w regionie promotorowym, wpływają na właściwości jakościowe enzymu. Gen CYP7A1, kodując kluczowy enzym w katabolizmie cholesterolu, jest głównym kandydatem do badań jego związku ze zmianami w osoczowym poziomie lipoprotein. Obecność wariantów genetycznych w promotorze genu CYP7A1 może być związana ze zmienionym poziomem cholesterolu całkowitego, triacylogliceroli czy LDL (Low- Density Lipoprotein). Polimorfizm promotora genu kodującego kluczowy enzym szlaku syntezy kwasów żółciowych i usuwania cholesterolu z organizmu jest głównym kandydatem do badań asocjacyjnych z takimi jednostkami chorobowymi, jak kamica żółciowa, nowotwory jelita grubego i woreczka żółciowego czy choroby o podłożu miażdżycowym

Dose distribution homogeneity in two TBI techniques—Analysis of 208 irradiated patients conducted in Stanislaw Leszczynski Memorial Hospital, Katowice

BackgroundTo analyze and compare dose distribution homogeneity in selected points (especially in the chest wall region) for patients irradiated with two different TBI techniques to achieve a uniform total dose (excluding lungs area) specified in the range of 11.4–14.0[[ce:hsp sp="0.25"/]]Gy.Material and methodsFrom August 2000 to December 2009, a group of 158 patients was treated by the use of 15[[ce:hsp sp="0.25"/]]MV photon irradiation consisting of six fractions: four opposed lateral and two anterior–posterior/posterior–anterior (AP/PA). Patients were irradiated with the fraction dose of 2[[ce:hsp sp="0.25"/]]Gy twice a day for 3 consecutive days. The prescribed dose to PC point (specified at intersection of the beam axis with the mid-plane of the patient irradiated laterally) was 12[[ce:hsp sp="0.25"/]]Gy. Since January 2010 until closing the study, another group of 50 patients was treated according to a modified protocol. The treatment was carried out in six lateral fractions only, twice a day, for three following days and a lateral lung shield was used for a part of total irradiation time. The measurements of doses in 20 selected points of patient's body were carried out by means of MOSFET detectors.ResultsThe modified TBI technique allows to achieve an expected homogenous dose in the points of interest similar to that obtained by using the initial protocol. The calculated and measured in vivo doses met the specified range of 11.4–14[[ce:hsp sp="0.25"/]]Gy for both applied TBI protocols.ConclusionsOur results indicate that for all patients the homogenous dose distribution in the specified range was achieved

The Impact of Blood Morphological Parameters on Treatment Outcomes in Tennis Elbow Patients Receiving Platelet-Rich Plasma (PRP) Therapy: A Prospective Study.

Platelet-rich plasma (PRP) therapy holds substantial promise for the treatment of tennis elbow, a complex and challenging musculoskeletal condition. The aim of the study was to assess whether there are correlations between the levels of individual morphotic elements determined in whole blood and the outcomes of tennis elbow treatment with PRP injection, as measured using patient-reported outcome measures (PROMs) such as the Visual Analog Scale (VAS), Quick Disabilities of the Arm, Shoulder, and Hand (QDASH), and Patient-Rated Tennis Elbow Evaluation (PRTEE). A prospective analysis was conducted on 107 patients (132 elbows) undergoing lateral epicondylitis treatment with (PRP) injections. Patients completed VAS, PRTEE, and QDASH questionnaires on the day of PRP administration and at established checkpoints (2, 4, 8, 12, 24, 52, and 104 weeks). Minimal clinically important difference (MCID) was employed to assess the treatment effects. Then, correlations were measured within each PROM, and the impact of the concentration of individual blood parameters on the MCID outcomes was assessed. Analyzing the relationships between the MCID+ and MCID- groups, significant correlations for the VAS and QDASH scales were observed. The level of individual morphotic elements in the blood may have influenced the treatment outcome, as measured using specific patient-reported outcome measures (PROMs). Regarding the VAS scale, factors favoring a positive treatment outcome included higher values of eosinophils (EOS) and basophils (BASO). For the QDASH scale, these factors were a lower value of mean corpuscular volume (MCV) and a higher mean corpuscular hemoglobin (MCH). The levels of certain blood parameters, such as EOS and BASO, in the current study influenced the classification of patients into MCID+ or MCID- groups, based on the VAS and QDASH scales

The rs2516839 Polymorphism of the USF1 Gene May Modulate Serum Triglyceride Levels in Response to Cigarette Smoking

Single nucleotide polymorphisms (SNPs) of the USF1 gene (upstream stimulatory factor 1) influence plasma lipid levels. This study aims to determine whether USF1 SNPs interact with traditional risk factors of atherosclerosis to increase coronary artery disease (CAD) risk. In the present study serum lipid levels and USF1 gene polymorphisms (rs2516839 and rs3737787) were determined in 470 subjects: 235 patients with premature CAD and 235 controls. A trend of increasing triglycerides (TG) levels in relation to the C allele dose of rs2516839 SNP was observed. The synergistic effect of cigarette smoking and C allele carrier state on CAD risk was also found (SIM = 2.69, p = 0.015). TG levels differentiated significantly particular genotypes in smokers (1.53 mmol/L for TT, 1.80 mmol/L for CT and 2.27 mmol/L for CC subjects). In contrast, these differences were not observed in the non-smokers subgroup (1.57 mmol/L for TT, 1.46 mmol/L for CT and 1.49 mmol/L for CC subjects). In conclusion, the rs2516839 polymorphism may modulate serum triglyceride levels in response to cigarette smoking. Carriers of the C allele seem to be particularly at risk of CAD, when exposed to cigarette smoking