Dosimetric comparison of MRI-based HDR brachytherapy and stereotactic radiotherapy in patients with advanced cervical cancer: A virtual brachytherapy study

AimTo evaluate the treatment plans of 3D image-guided brachytherapy (BT) and stereotactic robotic radiotherapy with online image guidance – CyberKnife (CK) in patients with locally advanced cervix cancer.Methods and materialsTen pairs of plans for patients with locally advanced inoperable cervical cancer were created using MR based 3D brachytherapy and stereotaxis CK. The dose that covers 98% of the target volume (HR CTV D98) was taken as a reference and other parameters were compared.ResultsOf the ten studied cases, the dose from D100 GTV was comparable for both devices, on average, the BT GTV D90 was 10–20% higher than for CK. The HR CTV D90 was higher for CK with an average difference of 10–20%, but only fifteen percent of HR CTV (the peripheral part) received a higher dose from CK, while 85% of the target volume received higher doses from BT. We found a significant organ-sparing effect of CK compared to brachytherapy (20–30% lower doses in 0.1 cm³, 1 cm³, and 2 cm³).ConclusionBT remains to be the best method for dose escalation. Due to the significant organ-sparing effect of CK, patients that are not candidates for BT could benefit from stereotaxis more than from classical external beam radiotherapy.     

Use of PTW-microDiamond for relative dosimetry of unflattened photon beams

PurposeThe increasing interest in SBRT treatments encourages the use of flattening filter free (FFF) beams. Aim of this work was to evaluate the performance of the PTW60019 microDiamond detector under 6 MV and 10MVFFF beams delivered with the EDGE accelerator (Varian Medical System, Palo Alto, USA). A flattened 6 MV beam was also considered for comparison.MethodsShort term stability, dose linearity and dose rate dependence were evaluated. Dose per pulse dependence was investigated in the range 0.2–2.2 mGy/pulse. MicroDiamond profiles and output factors (OFs) were compared to those obtained with other detectors for field sizes ranging from 40 × 40 cm² to 0.6 × 0.6 cm². In small fields, volume averaging effects were evaluated and the relevant correction factors were applied for each detector.ResultsMicroDiamond short term stability, dose linearity and dependence on monitor unit rate were less than 0.8% for all energies. Response variations with dose per pulse were found within 1.8%. MicroDiamond output factors (OF) values differed from those measured with the reference ion-chamber for less than 1% up to 40 × 40 cm² fields where silicon diodes overestimate the dose of ≈3%. For small fields (<3 × 3 cm²) microDiamond and the unshielded silicon diode were in good agreement.ConclusionsMicroDiamond showed optimal characteristics for relative dosimetry even under high dose rate beams. The effects due to dose per pulse dependence up to 2.2 mGy/pulse are negligible. Compared to other detectors, microDiamond provides accurate OF measurements in the whole range of field sizes. For fields <1 cm correction factors accounting for fluence perturbation and volume averaging could be required.     

Small field output factors evaluation with a microDiamond detector over 30 Italian centers

PurposeThe aim of the study was a multicenter evaluation of MLC&jaws-defined small field output factors (OF) for different linear accelerator manufacturers and for different beam energies using the latest synthetic single crystal diamond detector commercially available. The feasibility of providing an experimental OF data set, useful for on-site measurements validation, was also evaluated.MethodsThis work was performed in the framework of the Italian Association of Medical Physics (AIFM) SBRT working group. The project was subdivided in two phases: in the first phase each center measured OFs using their own routine detector for nominal field sizes ranging from 10 × 10 cm² to 0.6 × 0.6 cm². In the second phase, the measurements were repeated in all centers using the PTW 60019 microDiamond detector.ResultsThe project enrolled 30 Italian centers. Micro-ion chambers and silicon diodes were used for OF measurements in 24 and 6 centers respectively. Gafchromic films and TLDs were used for very small field OFs in 3 and 1 centers. Regarding the measurements performed with the user’s detectors, OF standard deviations (SD) for field sizes down to 2 × 2 cm² were in all cases <2.7%. In the second phase, a reduction of around 50% of the SD was obtained using the microDiamond detector.ConclusionsThe measured values presented in this multicenter study provide a consistent dataset for OFs that could be a useful tool for improving dosimetric procedures in centers. The microDiamond data present a small variation among the centers confirming that this detector can contribute to improve overall accuracy in radiotherapy.     

Monte Carlo study on the secondary cancer risk estimations for patients undergoing prostate radiotherapy: A humanoid phantom study

AimThe aim of this study was to estimate the secondary malignancy risk from the radiation in FFB prostate linac-based radiotherapy for different organs of the patient.BackgroundRadiation therapy is one of the main procedures of cancer treatment. However, the application the radiation may impose dose to organs of the patient which can be the cause of some malignancies.Materials and methodsMonte Carlo (MC) simulation was used to calculate radiation doses to patient organs in 18 MV linear accelerator (linac) based radiotherapy. A humanoid MC phantom was used to calculate the equivalent dose s for different organs and probability of secondary cancer, fatal and nonfatal risk, and other risks and parameters related to megavoltage radiation therapy. In out-of-field radiation calculation, it could be seen that neutrons imparted a higher dose to distant organs, and the dose to surrounding organs was mainly due to absorbed scattered photons and electron contamination.ResultsOur results showed that the bladder and skin with 54.89 × 10⁻³ mSv/Gy and 46.09 × 10⁻³ mSv/Gy, respectively, absorbed the highest equivalent dose s from photoneutrons, while a lower dose was absorbed by the lung at 3.42 × 10⁻³ mSv/Gy. The large intestine and bladder absorbed 55.00 × 10⁻³ mSv/Gy and 49.08 × 10⁻³, respectively, which were the highest equivalent dose s due to photons. The brain absorbed the lowest out-of-field dose, at 1.87 × 10⁻³ mSv/Gy.ConclusionsWe concluded that secondary neutron portion was higher than other radiation. Then, we recommended more attention to neutrons in the radiation protection in linac based high energy radiotherapy.     

Faisabilité et intérêt d’un nouvel algorithme de reconstruction des images TEP-18FDG (AW OSEM DR) pour la délimitation des volumes cibles en radiothérapie. À propos d’un cas de néoplasie ORL

ObjectiveWe compared two reconstruction methods for 18fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography (PET) images with “attenuation weighted ordered subset expectation maximization” using either the manufacturer-provided (AW-OSEM) or a “Detector response” (AW-OSEM DR) tomographic operator. We looked at the feasibility of using the latter reconstruction for radiotherapy target volumes definition in cancers of the superior aero-digestive tract (VADS). In this preliminary study, we first assessed the spatial resolution of images obtained with AW-OSEM and AW-OSEM DR on a Biograph™ 6, and secondly target volumes of radiotherapy “Gross Tumor Volume” (GTV), “Clinical Target Volume” (CTV) and “Planning Target Volume” (PTV) obtained with each of these reconstruction methods.Material and methodsThe spatial resolution was measured on a test object containing 4 radioactive point sources. Furthermore, radiotherapy target volumes have been defined with the software Eclipse™ on injected scanner (CT IV) and PET/CT (PET AW-OSEM and PET AW-OSEM DR) images.ResultsSpatial resolution was improved with AW-OSEM DR algorithm reconstruction compared to images obtained with AW-OSEM reconstruction (from 7.5 mm down to 5.4 mm for the highest reduction). GTV from AW-OSEM DR reconstruction with 42 and 50% of the “Standard uptake value maximum” (SUVmax) semi-automatic threshold (1.2 and 0.7 cm³ respectively) were lower than those obtained with AW-OSEM (3.6 and 2.2 cm³ respectively). They were also lower than GTV defined with CT IV (5.5 cm³). It was the same for CTV and PTV.ConclusionThis study showed that AW-OSEM DR reconstruction method allows less impaired spatial resolution than AW-OSEM. In the case of radiotherapy target volumes delineation, AW-OSEM DR may decrease the GTV, CTV and PTV and therefore the risk of side effects associated with organs at risk.     

Small field characterization of a Nanochamber prototype under flattening filter free photon beams

IntroductionNanochambers present some advantages in terms of energy independence and absolute dose measurement for small field dosimetry in the SBRT scenario. Characterization of a micro-chamber prototype was carried out both under flattened and flattening-filter-free (FFF) beams with particular focus on stem effect.MethodsThe study included characterization of leakage and stem effects, dose rate and dose per pulse dependence, measurement of profiles, and percentage depth doses (PDDs). Ion collection efficiency and polarity effects were measured and evaluated against field size and dose per pulse. The 6_MV, 6_MV_FFF and 10_MV FFF beams of a Varian EDGE were used. Output factors were measured for field sizes ranging from 0.8 × 0.8 cm² to 20 × 20 cm² and were compared with other detectors.ResultsThe 2 mm diameter of this chamber guarantees a high spatial resolution with low penumbra values. In orthogonal configuration a strong stem (and cable) effect was observed for small fields. Dose rate and dose per pulse dependence were <0.3% and 0.6% respectively for the whole range of considered values. The Nanochamber exhibits a field size (FS) dependence of the polarity correction >2%. The OF values were compared with other small field detectors showing a good agreement for field sizes >2 × 2 cm². The large field over-response was corrected applying k_pol(FS).ConclusionsNanochamber is an interesting option for small field measurements. The spherical shape of the active volume is an advantage in terms of reduced angular dependence. An interesting feature of the Nanochamber is its beam quality independence and, as a future development, the possibility to use it for small field absolute dosimetry.     

Experimental assessment of proton dose calculation accuracy in inhomogeneous media

PurposeProton therapy with Pencil Beam Scanning (PBS) has the potential to improve radiotherapy treatments. Unfortunately, its promises are jeopardized by the sensitivity of the dose distributions to uncertainties, including dose calculation accuracy in inhomogeneous media. Monte Carlo dose engines (MC) are expected to handle heterogeneities better than analytical algorithms like the pencil-beam convolution algorithm (PBA). In this study, an experimental phantom has been devised to maximize the effect of heterogeneities and to quantify the capability of several dose engines (MC and PBA) to handle these.MethodsAn inhomogeneous phantom made of water surrounding a long insert of bone tissue substitute (1 × 10 × 10 cm³) was irradiated with a mono-energetic PBS field (10 × 10 cm²). A 2D ion chamber array (MatriXX, IBA Dosimetry GmbH) lied right behind the bone. The beam energy was such that the expected range of the protons exceeded the detector position in water and did not attain it in bone. The measurement was compared to the following engines: Geant4.9.5, PENH, MCsquare, as well as the MC and PBA algorithms of RayStation (RaySearch Laboratories AB).ResultsFor a γ-index criteria of 2%/2 mm, the passing rates are 93.8% for Geant4.9.5, 97.4% for PENH, 93.4% for MCsquare, 95.9% for RayStation MC, and 44.7% for PBA. The differences in γ-index passing rates between MC and RayStation PBA calculations can exceed 50%.ConclusionThe performance of dose calculation algorithms in highly inhomogeneous media was evaluated in a dedicated experiment. MC dose engines performed overall satisfactorily while large deviations were observed with PBA as expected.     

Measurement of stray neutron doses inside the treatment room from a proton pencil beam scanning system

PurposeTo measure the environmental doses from stray neutrons in the vicinity of a solid slab phantom as a function of beam energy, field size and modulation width, using the proton pencil beam scanning (PBS) technique.MethodMeasurements were carried out using two extended range WENDI-II rem-counters and three tissue equivalent proportional counters. Detectors were suitably placed at different distances around the RW3 slab phantom. Beam irradiation parameters were varied to cover the clinical ranges of proton beam energies (100–220 MeV), field sizes ((2 × 2)–(20 × 20) cm²) and modulation widths (0–15 cm).ResultsFor pristine proton peak irradiations, large variations of neutron H¹(10)/D were observed with changes in beam energy and field size, while these were less dependent on modulation widths. H¹(10)/D for pristine proton pencil beams varied between 0.04 μSv Gy⁻¹ at beam energy 100 MeV and a (2 × 2) cm² field at 2.25 m distance and 90° angle with respect to the beam axis, and 72.3 μSv Gy⁻¹ at beam energy 200 MeV and a (20 × 20) cm² field at 1 m distance along the beam axis.ConclusionsThe obtained results will be useful in benchmarking Monte Carlo calculations of proton radiotherapy in PBS mode and in estimating the exposure to stray radiation of the patient. Such estimates may be facilitated by the obtained best-fitted simple analytical formulae relating the stray neutron doses at points of interest with beam irradiation parameters.     

Postoperative endometrial carcinoma treated with external beam irradiation plus vaginal-cuff brachytherapy. Is there a dose relationship with G2 vaginal complications?

AimTo analyse the possible relationship between the EQD2_(α/β=3Gy) at 2 cm³ of the vagina and late toxicity in vaginal-cuff-brachytherapy (VBT) after external-beam-irradiation (EBRT) for postoperative endometrial carcinoma (EC).Materials and methodsFrom 2014 to 2016, 62 postoperative EC patients were treated with EBRT + VBT. The median EBRT dose was 45 Gy (44 Gy–50.4 Gy). VBT involved a single 7 Gy dose. Toxicity was prospectively evaluated using the RTOG score for the rectum and bladder and the objective LENT-SOMA criteria for the vagina. EQD2_{(α/β = 3Gy)} at 2 cm³ of the most exposed part of the vagina was calculated by the sum of the EBRT + VBT dose. Statistics: Boxplot, Student’s t and Chi-square tests and ROC curves.ResultsMean follow-up: 39.2 months (15–68). Late toxicity: bladder:0 patient; rectum:2 patients-G1; Vagina: 26 patients-17G1, 9G2; median EQD2_(α/β=3Gy) at 2 cm³ in G0-G1 patients was 70.4 Gy(SD2.36), being 72.5 Gy(SD2.94) for G2p. The boxplot suggested a cut-point identifying the absence of G2: 100 % of G2p received >68 Gy, ROC curves showed an area under the curve of 0.72 (sensitivity of 1 and specificity of 0.15).ConclusionsDoses >68 Gy EQD2_(α/β=3Gy) at 2 cm³ to the most exposed area of the vagina were associated with late G2 vaginal toxicity in postoperative EC patients treated with EBRT + VBT suggesting a very good dose limit to eliminate the risk of G2 late toxicity. The specificity obtained indicates the need for prospective analyses.     

Inflammatory intestinal damage induced by 5-fluorouracil requires IL-4

Background5-Fluorouracil (5-FU) induces intestinal mucositis, which is characterized by epithelial ulcerations in the mucosa and clinical manifestations, such as pain and dyspeptic symptoms. Cytokines participate in the inflammatory and functional events of intestinal mucositis. IL-4 is an important mediator of intestinal inflammation, with either anti-inflammatory or pro-inflammatory functions, depending on the model of intestinal inflammation. This study aimed to evaluate the role of IL-4 in 5-FU-induced intestinal mucositis.MethodsIL-4^+/+ or IL-4^?/? mice (25–30 g) were intraperitoneally injected with 5-FU (450 mg/Kg) or saline (C). After 3 days, the mice were sacrificed and the duodenum was evaluated for epithelial damage, MPO activity and cytokine concentration.Results5-FU induced significant damage in the intestinal epithelium of IL-4^+/+ mice (reduction in the villus/crypt ratio: control = 3.31 ± 0.21 μm, 5-FU = 0.99 ± 0.10 μm). However, the same treatment did not induce significant damage in IL-4^?/? mice (5-FU = 2.87 ± 0.19 μm) compared to wild-type mice. 5-FU-induced epithelial damage increased the MPO activity (neutrophil number) and the level of pro-inflammatory cytokines (IL-4, TNF-α, IL-1β and CXCL-8) in the duodenum. These results were not observed in IL-4^?/? mice treated with 5-FU.ConclusionOur data suggest that IL-4 participates as a pro-inflammatory cytokine in a 5-FU-induced intestinal damage model and suggests that IL-4 antagonists may be novel therapeutics for this condition.     

Dosimetric characterization of small fields using a plastic scintillator detector: A large multicenter study

PurposeIn modern radiation therapy accurate small fields dosimetry is a challenge and its standardization is fundamental to harmonize delivered dose in different institutions. This study presents a multicenter characterization of MLC-defined small field for Elekta and Varian linear accelerators. Measurements were performed using the Exradin W1 plastic scintillator detector.Materials and methodsThe project enrolled 24 Italian centers. Each center performed Tissue Phantom Ratio (TPR), in-plane and cross-plane dose profiles of 0.8 × 0.8 cm² field, and Output Factor (OF) measurements for square field sizes ranging from 0.8 to 10 cm. Set-up conditions were 10 cm depth in water phantom at SSD 90 cm. Measurements were performed using two twin Exradin W1 plastic scintillator detectors (PSD) correcting for the Cerenkov effect as proposed by the manufacturer.ResultsData analysis from 12 Varian and 12 Elekta centers was performed. Measurements of 7 centers were not included due to cable problems. TPR measurements showed standard deviations (SD) < 1%; SD < 0.4 mm for the profile penumbra was obtained, while FWHM measurements showed SD < 0.5 mm. OF measurements showed SD < 1.5% for field size greater than 2 × 2 cm². Median OFs values were in agreement with the recent bibliography.ConclusionsHigh degree of consistency was registered for all the considered parameters. This work confirmed the importance of multicenter dosimetric intercomparison. W1 PSD could be considered as a good candidate for small field measurements.     

Préconditionnement laser en site osseux membraneux : mise au point d’un modèle d’étude

ObjectiveThe application of a supraphysiologic stress (preconditioning) prior to an injury induces cellular and tissular resistance on soft tissues. The aim of this study is to evaluate X-ray irradiated bone healing with and without laser preconditioning.Materials and methodsThe laser shot is defined to induce a controlled increase of the bone temperature. Then, bone healing is in vivo observed through the evolution of the vascularization process. Optical chambers implanted on the skull of 20 rabbits allow the weekly observation of bone vascular plexus during 12 weeks. An original image processing determines the vascular density (VD) on four groups: #1: control group (n = 5); #2: laser treatment (n = 5); #3: X-ray irradiation (n = 5); #4: laser preconditioning prior to X-ray irradiation (n = 5).ResultsPreconditioning is performed by a diode-laser (815 nm, 36 J/cm²). VD remains stable during the 12-week follow up for groups #1 and #2. X-ray radiation induces a significant decrease of the vascular network in groups #3 and #4 compared to the group #1 (p < 0.001). However, the decrease of the vascularization is limited in group #4 versus group #3 (p < 0.05).DiscussionThis in vivo original model reproducibly evaluates VD and the impact of different stresses on bone healing. Laser treatment is a controlled heating method, which preserves the vascular network of X-ray irradiated bone. This innovative approach promotes the bone healing in which the vascular supply has been damaged.     

Comparaison entre OSEM-3D et rétroprojection filtrée pour les images traitées par SISCOM dans l’épilepsie temporale

IntroductionWhen ictal and interictal brain SPECT are reconstructed with filtered backprojection (FBP), the noise level of subtraction images is frequently high and requires the use of thresholding methods. The aim of this study was to compare the subtraction images for cerebral SPECT reconstructed either with FBP or with a 3D iterative reconstruction method (OSEM-3D).Material and methodsAfter optimisation of the reconstruction parameters on phantom, the subtraction SPECT images, which were obtained with FBP or with OSEM-3D and coregistered with MRI images, were analyzed in 15 patients with refractory temporal epilepsy.ResultsOn phantom and with the constrain of high enough spatial resolution (full width at half of maximum for a punctual source less than or equal to 11 mm) were reached using: (i) a Butterworth filter with a cut-off frequency of 0.4 Nyquist at order 6 for FBP and (ii) five iterations, 16 subsets and a 9 mm gaussian filter for OSEM-3D. On the subtraction images, which were obtained with these optimal parameters, the temporal foci from patients were smaller with OSEM-3D than with FBP (11 ± 6 cm³ versus 17 ± 10 cm³, P = 0.02), mean voxel activities were equivalent between the two methods within temporal foci (6.30 ± 3.13 counts versus 6.34 ± 4.93 counts) but these activities were dramatically reduced by OSEM-3D within background regions (0.02 ± 0.02 counts versus 0.19 ± 0.12 counts, P < 0.001).ConclusionFor the ictal–interictal subtraction SPECT images, which are obtained in patients with refractory temporal epilepsy, the use of an optimized OSEM-3D method leads to dramatically reduce the volume of temporal foci, as well as the background noise level, two properties that are likely to facilitate the detection and localisation of epilepsy foci.     

Adsorption characteristics of sulfur powder by bamboo charcoal to restrain sulfur allergies

Exposures to particulate matter with a diameter of 2.5 μm or less (PM2.5) may influence the risk of birth defects and make you allergic, which causes serious harm to human health. Bamboo charcoal can adsorb harmful substances,that was of benefitto people’s health. In order to figure out the optimal adsorbtion condition and the intrinsic change of bamboo charcoal, five chemicals were adsorbed by bamboo charcoal and were analyzed by FT-IR. The optimal blast time was 80 min of Na₂SO₃, 100 min of Na₂S₂O₈, 20 min of Na₂SO₄, 120 min of Fe₂(SO₄)₃ and 60 min or 100 min of S. FT-IR spectra showed that bamboo charcoal had five characteristic peaks of SS stretch, H₂O stretch, OH stretch, CO stretch or CC stretch, and NO₂ stretch at 3850 cm⁻¹, 3740 cm⁻¹, 3430 cm⁻¹, 1630 cm⁻¹ and 1530 cm⁻¹, respectively. For Na₂SO₃, the peaks at 3850 cm⁻¹, 3740 cm⁻¹, 3430 cm⁻¹, 1630 cm⁻¹ and 1530 cm⁻¹ achieved the maximum at 20 min. For Na₂S₂O₈, the peaks at 3850 cm⁻¹, 3740 cm⁻¹, 3430 cm⁻¹ and 1530 cm⁻¹ achieved the maximum at 40 min. For Na₂SO₄, the peaks at 3850 cm⁻¹, 3740 cm⁻¹ and 1530 cm⁻¹ achieved the maximum at 40 min. For Fe₂(SO₄)₃, the peaks at 3850 cm⁻¹, 3740 cm⁻¹, 1630 cm⁻¹ and 1530 cm⁻¹ achieved the maximum at 120 min. For S, the peaks at 3850 cm⁻¹ and 3740 cm⁻¹ achieved the maximum at 40 min, the peaks at 1630 cm⁻¹ and 1530 cm⁻¹ achieved the maximum at 40 min. It proved that bamboo charcoal could remove sulfur powder from air to restrain sulfur allergies.     

The determination of a dose deposited in reference medium due to (p,n) reaction occurring during proton therapy

AimThe aim of the investigation was to determine the undesirable dose coming from neutrons produced in reactions (p,n) in irradiated tissues represented by water.BackgroundProduction of neutrons in the system of beam collimators and in irradiated tissues is the undesirable phenomenon related to the application of protons in radiotherapy. It makes that proton beams are contaminated by neutrons and patients receive the undesirable neutron dose.Materials and methodsThe investigation was based on the Monte Carlo simulations (GEANT4 code). The calculations were performed for five energies of protons: 50 MeV, 55 MeV, 60 MeV, 65 MeV and 75 MeV. The neutron doses were calculated on the basis of the neutron fluence and neutron energy spectra derived from simulations and by means of the neutron fluence–dose conversion coefficients taken from the ICRP dosimetry protocol no. 74 for the antero-posterior irradiation geometry.ResultsThe obtained neutron doses are much less than the proton ones. They do not exceed 0.1%, 0.4%, 0.5%, 0.6% and 0.7% of the total dose at a given depth for the primary protons with energy of 50 MeV, 55 MeV, 60 MeV, 65 MeV and 70 MeV, respectively.ConclusionsThe neutron production takes place mainly along the central axis of the beam. The maximum neutron dose appears at about a half of the depth of the maximum proton dose (Bragg peak), i.e. in the volume of a healthy tissue. The doses of neutrons produced in the irradiated medium (water) are about two orders of magnitude less than the proton doses for the considered range of energy of protons.     

Mesenchymal stromal cell-conditioned medium prevents radiation-induced small intestine injury in mice

Background aimsEffective therapy for radiation-induced intestinal injury is currently unavailable. Mesenchymal stromal cells (MSC) are expected to be useful in repairing intestinal damage caused by irradiation. We determined whether the MSC-derived bioactive components could protect radiation-induced small intestine injury in miceMethodsHuman umbilical cord (UC)-derived MSC were isolated, expanded and exposed to hypoxic conditions in vitro. The hypoxia-conditioned medium was ultrafiltrated with a 3-kDa molecular weight cut-off to prepare the high molecular weight fraction (HMWF). The effect of HMWF on the viability of irradiated rat intestinal epithelial cells (IEC-6) was examined by MTT(methyl thiazolyl tetrazolium) assay. HMWF was also delivered to BALB/C male mice by tail intravenous injection immediately after receiving local abdominal irradiation at a selected dose of 10 Gy. Animal body weight, survival and diarrhea were monitored for 30 days. The improvement of mice intestine structure, including epithelium thickness and villus height, was examined by histologyResultsHMWF enhanced the viability of irradiated IEC-6 cells in vitro. Repeated infusion of HMWF for 7 days immediately after abdominal irradiation of 10 Gy (⁶⁰Coγ-ray) increased the survival rate, decreased diarrhea occurrence and improved the small intestinal structural integrity of irradiated miceConclusionsMSC-derived bioactive components could be a novel therapeutic approach for the treatment of radiation-induced injury.     

Post-chemotherapy target volumes are safe as boost volume for intact breast radiotherapy in locally advanced breast cancer

PurposeThe purpose of our study is to evaluate the challenges in identification of postoperative complexes (POC), the utility of clips in delineation of clinical target volume for boost in LABC downstaged with neoadjuvant chemotherapy (NACT) and to correlate this with patterns of recurrence.Methods and materialsLABC patients who underwent NACT followed by BCS and radiotherapy (2007–2014) were the subject of our analysis. The data on visibility and characteristics of postoperative cavity (POC), concordance of its volume with clip volume on radiation planning scan were retrieved. A 1 cm margin beyond POC was delineated as a clinical target volume (CTV). Postoperative whole breast and supraclavicular radiotherapy (50 Gy/25fractions/5wk or 42.4 Gy/16#/3 wk) followed by boost (10−16 Gy/5-8#/1–1.5wk) were delivered. Patterns of recurrence were evaluated.ResultsOut of 60 patients, 28.3% patients had stage II disease and 71.7% had stage III disease. 25% patients achieved pathological CR (complete response). The median POC volume was 30 cc and the median clip volume was 40 cc. The concordance of POC volume with clip volume was seen in 80%. Clips served as a good surrogate for POC in 80% of patients. At a median follow-up of 65 months (IQ range 32–84 months), and a lost to follow-up rate of 11.6 %, 3.3% (n = 2) patients had local recurrence (LR) and 8.3% (n = 5) had regional recurrence (LRR) in the supraclavicular region.ConclusionsDelineation of post NACT excision cavity as POC for boost radiotherapy is safe. Clips serve as a good surrogate for CTV delineation in 75% patients.