19 research outputs found
Radiotherapy forward and inverse problem applying Boltzmann transport equation (SÀdehoidon suora ja kÀÀnteisongelma Boltzmannin siirtoyhtÀlön avulla)
Utilization of untreated and formaldhyde treated skimmilk powder and skimmilk powder-barley pellets by ruminants
The utilization of spray-dried fat free milk powder in three different froms 1) untreated, 2) treated with formaldehyde (0.4 g formaldehyde/100 g crude protein) and 3) pelleted with barley meal (30 % milk powder and 70 % barley meal) was studied with three rumen-fistulated dairy cows according to a 3 x 3 Latin square. The effects of different treatments were investigated with respect to rumen fermentation, microbial determinations and milk and blood analyses. The basic feed in every diet consisted of hay, grass silage, barley, oats, mineral and vitamin mixtures. Feeding was according to nutrient requirement. In each diet 25 % of the DCP required for milk production was replaced with milk protein. The NH3 concentration in the rumen fluid was lowest on the pelleted diet followed by the formaldehyde treated and untreated skimmilk powder diets, the differences only being significant between the pelleted and untreated diets. The pH values were significantly higher on the pelleted diet than on the other diets. The VFA content of the rumen fluid was similar on the different diets. The total amount of rumen ciliates was highest on the untreated skimmilk powder diet and lowest on the pelleted diet. The quantity of bacteria was however lower on the untreated skimmilk powder diet than on the other diets. Bacteria constituted 72â88 % of the total microbe mass on the different diets. The total microbe mass consisted of the following percentages of rumen content on the different diets: untreated 3.3 %, formaldehyde treated 3.2 % and pelleted diet 2,9 %. No effects on the milk yields and blood contents were found with the different treatments of skimmilk powder. Milk protein-% was significantly higher on the untreated skimmilk powder diet than on the pelleted diet
Troponin T-release associates with cardiac radiation doses during adjuvant left-sided breast cancer radiotherapy
Background
Adjuvant radiotherapy (RT) for left-sided breast cancer increases cardiac morbidity and mortality. For the heart, no safe radiation threshold has been established. Troponin T is a sensitive marker of myocardial damage. Our aim was to evaluate the effect of left-sided breast cancer RT on serum high sensitivity troponin T (hscTnT) levels and its association with cardiac radiation doses and echocardiographic parameters.
Methods
A total of 58 patients with an early stage, left-sided breast cancer or ductal carcinoma in situ (DCIS) who received adjuvant breast RT without prior chemotherapy were included in this prospective, non-randomized study. Serum samples were taken before, during and after RT. An increase of hscTnT >30 % was predefined as significant. A comprehensive 2D echocardiograph and electrocardiogram (ECG) were performed before and after RT. Dose-volume histograms (DVHs) were generated for different cardiac structures.
Results
The hscTnT increased during RT from baseline in 12/58 patients (21 %). Patients with increased hscTnT values (group A, Nâ=â12) had significantly higher radiation doses for the whole heart (pâ=â0.02) and left ventricle (pâ=â0.03) than patients without hscTnT increase (group B, Nâ=â46). For the left anterior descending artery (LAD), differences between groups A and B were found in volumes receiving 15 Gy (pâ=â0.03) and 20 Gy (pâ=â0.03) Furthermore, after RT, the interventricular septum thickened (pâ=â0.01), and the deceleration time was prolonged (pâ=â0.008) more in group A than in group B.
Conclusions
The increase in hscTnT level during adjuvant RT was positively associated with the cardiac radiation doses for the whole heart and LV in chemotherapy-naive breast cancer patients. Whether these acute subclinical changes increase the risk of excessive long-term cardiovascular morbidity or mortality, will be addressed in the follow-up of our patients.BioMed Central open acces
Utilization of untreated and formaldhyde treated skimmilk powder and skimmilk powder-barley pellets by ruminants
vokKirjasto Aj-KKÀsittelemÀtön, formaldehydillÀ kÀsitellyn ja ohran kanssa pelletoidun maitojauheen hyvÀksikÀyttö mÀrehtijöill
KÀsittelemÀttömÀn, formaldehydillÀ kÀsitellyn ja ohran kanssa pelletoidun maitojauheen hyvÀksikÀyttö mÀrehtijöillÀ
The utilization of spray-dried fat free milk powder in three different froms 1) untreated, 2) treated with formaldehyde (0.4 g formaldehyde/100 g crude protein) and 3) pelleted with barley meal (30 % milk powder and 70 % barley meal) was studied with three rumen-fistulated dairy cows according to a 3 x 3 Latin square. The effects of different treatments were investigated with respect to rumen fermentation, microbial determinations and milk and blood analyses. The basic feed in every diet consisted of hay, grass silage, barley, oats, mineral and vitamin mixtures. Feeding was according to nutrient requirement. In each diet 25 % of the DCP required for milk production was replaced with milk protein. The NH3 concentration in the rumen fluid was lowest on the pelleted diet followed by the formaldehyde treated and untreated skimmilk powder diets, the differences only being significant between the pelleted and untreated diets. The pH values were significantly higher on the pelleted diet than on the other diets. The VFA content of the rumen fluid was similar on the different diets. The total amount of rumen ciliates was highest on the untreated skimmilk powder diet and lowest on the pelleted diet. The quantity of bacteria was however lower on the untreated skimmilk powder diet than on the other diets. Bacteria constituted 72â88 % of the total microbe mass on the different diets. The total microbe mass consisted of the following percentages of rumen content on the different diets: untreated 3.3 %, formaldehyde treated 3.2 % and pelleted diet 2,9 %. No effects on the milk yields and blood contents were found with the different treatments of skimmilk powder. Milk protein-% was significantly higher on the untreated skimmilk powder diet than on the pelleted diet.Maitovalkuaisen hyvĂ€ksikĂ€yttöÀ mĂ€rehtijĂ€llĂ€ tutkittiin kolmella eri tavoin kĂ€sitellyllĂ€ sumutuskuivatulla rasvattomalla maitojauheella: 1) KĂ€sittelemĂ€tön maitojauhe 2) FormaldehydillĂ€ kĂ€sitelty maitojauhe (0.4 g formaldehydiĂ€/100 g raakavalkuaista) 3) Pelletoitu maitojauhe (30 % maitojauhetta ja 70 % ohrajauhoa) Koe suoritettiin pötsifistelillĂ€ varustetulla kolmella lypsylehmĂ€llĂ€ 3x3 latinalaisen neliön mukaan. Jokaisen koejakson pituus oli kaksi viikkoa. Perusrehuina olivat heinĂ€, sĂ€ilörehu ja propionihapolla sĂ€ilötty ohra ja kaura sekĂ€ kivennĂ€is- ja vitamiinirehut. Ruokinta oli ravinnontarpeen mukainen. Jokaisessa dieetissĂ€ korvattiin 25 % maidontuotantoon tarvittavasta valkuaisesta maitovalkuaisella. Eri kĂ€sittelyjen vaikutusta maitovalkuaisen hyvĂ€ksikĂ€yttöön selvitettiin pötsineste-, veri ja maitonĂ€ytteiden perusteella. PötsistĂ€ otettiin jokaisen koejakson kahtena viimeisenĂ€ pĂ€ivĂ€nĂ€ kuusi nĂ€ytettĂ€ (ennen ruokintaa eli klo 04.45 ja ruokinnan jĂ€lkeen klo 06, 07, 08, 11 ja 13), joista mÀÀritettiin pH, ammoniakki, haihtuvat rasvahapot sekĂ€ pötsimikrobien mÀÀrĂ€ ja laatu. PelleteissĂ€ olevan maitovalkuaisen hajoaminen pötsissĂ€ oli hitaampaa kuin formaldehydillĂ€ kĂ€sitellyn ja kĂ€sittelemĂ€ttömĂ€n maitovalkuaisen. TĂ€tĂ€ osoittaa se, ettĂ€ pötsinesteen ammoniakkipitoisuus oli alhaisin pellettidieetillĂ€. Myös formaldehydilla kĂ€siteltyĂ€ maitojauhetta sisĂ€ltĂ€vĂ€llĂ€ dieetillĂ€ se oli jonkin verran alhaisempi kuin kĂ€sittelemĂ€töntĂ€ maitojauhetta sisĂ€ltĂ€vĂ€llĂ€ dieetillĂ€. Erot olivat tilastollisesti merkitseviĂ€ kuitenkin vain pellettidieetin ja kĂ€sittelemĂ€töntĂ€ maitojauhetta sisĂ€ltĂ€vĂ€n dieetin vĂ€lillĂ€. Pötsinesteen pH-arvot olivat korkeammat pellettidieetillĂ€ kuin muilla dieeteillĂ€. Ne pysyivĂ€t kuitenkin kaikilla dieeteillĂ€ normaaliarvojen rajoissa. Pötsinesteen haihtuvien rasvahappojen mÀÀrissĂ€ ei ollut merkitseviĂ€ eroja eri dieeteillĂ€. Pötsin alkuelĂ€inten mÀÀrĂ€ oli suurin kĂ€sittelemĂ€töntĂ€ maitojauhetta sisĂ€ltĂ€vĂ€llĂ€ dieetillĂ€ ja pienin pellettidieetillĂ€. Bakteereita sen sijaan oli vĂ€hiten edellisellĂ€ dieetillĂ€. Bakteereiden osuus mikrobiston kokonaismassasta vaihteli eri dieeteillĂ€ 72â88 % pienimmĂ€n luvun ollessa kĂ€sittelemĂ€töntĂ€ maitovalkuaista sisĂ€ltĂ€vĂ€llĂ€ dieetillĂ€ ja suurimman pellettidieetillĂ€. Koko mikrobimassan prosenttinen osuus pötsin sisĂ€llön tilavuudesta oli eri dieeteillĂ€ seuraava: kĂ€sittelemĂ€tön maitojauhedieetti 3.3 %, formaldehydillĂ€ kĂ€sitelty 3.2 % ja pellettidieetti 2.9 % MaitomÀÀrissĂ€ sekĂ€ veriarvoissa ei ollut eroja eri dieettien vĂ€lillĂ€. Maidon valkuaisprosentti sensijaan oli merkitsevĂ€sti korkeampi kĂ€sittelemĂ€töntĂ€ maitovalkuaista sisĂ€ltĂ€vĂ€llĂ€ dieetillĂ€ kuin pellettidieetillĂ€
Utilization of untreated and formaldhyde treated skimmilk powder and skimmilk powder-barley pellets by ruminants
Validation of HDR brachytherapy doses in the treatment of keloid scars using the egs_brachy Monte Carlo application
Objective. Radiotherapy is a well-known alternative in the treatment of keloid scars to reduce the recurrence of scars. The purpose of this study was to investigate the feasibility and accuracy of dose delivered from a high-dose-rate (HDR) afterloaders in keloid scar brachytherapy using Monte Carlo (MC) simulations and measurements. Approach. Treatment doses and central axis dose profiles were measured using radiophotoluminescence dosimeters and radiochromic films, respectively, with two HDR afterloaders, both using an Ir-192 source, in a phantom made of solid water and polycarbonate sheets. The nominal treatment dose calculated by the AAPM Task Group No. 43 (TG-43) dose model was set to 8.5 Gy at a distance of 0.5 cm laterally from the middle of the source line located in a plastic applicator simulating a 15 cm long surgically removed scar treatment with 30 equally spaced (0.5 cm) source positions. The dose profiles were measured at three different distances from the applicator and the absolute doses at four points at different distances. MC simulations were performed using the egs_brachy, which is based on EGSnrc code system. Main results. The measured and simulated dose profiles match well, especially at 10.0 mm (difference <1%) and 15.0 mm depths (difference <4%), and with a small dose difference at 5.0 mm depth (difference <4%). Point dose measurements agreed well in the dose maximum area (difference <7%) with the simulated dose profiles, although the largest difference near the edge of the profile was <30%. The dose differences between the TG-43 dose model and the MC simulation were small (differences <4%). Significance. Simulated and measured dose levels at a depth of 0.5 cm showed that the nominal treatment dose can be achieved with the utilized setup. The measurement results of the absolute dose agree well with the corresponding simulation results.publishedVersionPeer reviewe
Treatment plan dosimetric impact after catheter stretch during multi-catheter interstitial breast brachytherapy
Purpose: Nylon 6/6 interstitial brachytherapy catheters may stretch when exposed to moisture, mechanical tension, and body temperature. The purpose of this study is to evaluate the magnitude of catheter stretch during a course of multi-catheter interstitial breast brachytherapy for nylon 6/6 treatment catheters, and to assess the impact this has on treatment plan dosimetry.
Material and methods : Catheters were exposed to water at 37°C for six days and the internal catheter length change (âL_W) was measured daily. Additionally, the measured internal catheter length change (âL_P), performed prior to each treatment fraction, for seven interstitial breast brachytherapy patients (total of 76 catheters) were retrospectively analyzed. The maximum length change seen in âL_P and âL_W were introduced as a source positional error to retrospective treatment plans, and treatment plan dosimetry was analyzed.
Results : âL_W and âL_P were on average +4.0% and +1.6% of the catheter lengths in water or tissue after 48 hours. Weak correlation was seen between the average âL_P per catheter and both the catheter length within tissue (Ï = 0.36, p = 0.0007), and the mid-catheter depth in tissue (Ï = 0.42, p < 0.0001). The D90CTV decreased 1.5% (p < 0.05) and 8.2% (p < 0.05) when the âL_P and âL_W were introduced to the initial plans.
Conclusions : Nylon 6/6 catheters stretch during a course of multi-catheter interstitial breast brachytherapy treatment. The observed stretch may affect treatment plan dosimetry, if the catheter internal length is only measured immediately after the insertion. Additional catheter length checks are recommended to verify the actual catheter internal length during the treatment
Dosimetric comparison of surface mould HDR brachytherapy with VMAT
Abstract Introduction The aim of this study was to investigate the dosimetric differences between surface mould highâdoseârate (HDR) brachytherapy and external beam volumetricâmodulated arc therapy (VMAT) for two treatment sites. Methods Previously treated HDR brachytherapy surface mould scalp (n = 4) and lower leg (n = 3) treatments were retrospectively analysed. The VMAT plans were optimised using an additional 3âmm setup margin on the clinical target volume (CTV) of the previously treated HDR plans. The HDR plans were calculated and normalised using the TGâ43 formalism and recalculated with Acuros BV (AC). Results On average, the mean brain and normal tissue doses were reduced by 44.8% and 27.4% for scalp and lower leg VMAT cases, respectively, when compared to AC calculated HDR plans. For VMAT plans, the average dose to a 1âmm thick skin structure deep to the target volume was not any lower than that in AC HDR plans. On average, the CTV coverage was 13.8% and 9.6% lower for scalp cases with AC dose calculation than with TGâ43 and 8.3% and 5.3% lower for lower leg cases if 0â or 1âcm backscatter material was applied above the catheters, respectively. Conclusions VMAT is a feasible treatment option in the case of extensive skin malignancies of the scalp and lower leg. Uncertainties related to delivered dose with HDR brachytherapy when using the TGâ43 dose calculation model or possible air gaps between the mould and skin favour the use of VMAT. The potential soft tissue deformation needs to be considered if VMAT is used