In situ radiotherapy for gastric cancer: The role of gold and other inorganic nanoparticles.

The use of X-rays as a first-line treatment for gastric tumors is constrained by inaccurate target delineation and high toxicity to surrounding healthy tissues. The potential of inorganic nanoparticles (INPs; e.g.

Polycaprolactone (PCL)-Gelatin Electrospun Meshes for Accelerated Gastric Wound Healing.

Gastric wound healing constitutes a complex challenge, even in the context of superficial wounds, due to the harsh stomach environment, characterized by high pH variability and dynamic enzyme concentrations. Therefore, effective healing depends on robust mechanical support and adequate biochemical cues to drive cell growth and proliferation. Electrospun-based dressings may offer a solution to these problems by providing physical support that mimics native extracellular matrix.

Development of an independent MU calculation software for radiotherapy treatments with stereotactic cones.

Purpose: Development of an independent MU calculator (StereoCalc) with and without heterogeneity corrections for stereotactic treatments, in a Varian TrueBeam STx LINAC using stereotactic cones, with flattening filter-free photon energies.

Methods: Multiple depth curves and output factors were measured, following the dosimetry formalism for small fields proposed by the TRS-483. The developed StereoCalc imports and processes the beam data files and calculates the patient plans with and without heterogeneity correction.

Evaluation of the role of mitochondria in the non-targeted effects of ionizing radiation using cybrid cellular models.

Radiobiology is moving towards a better understanding of the intercellular signaling that occurs upon radiation and how its effects relate to the dose applied. The mitochondrial role in orchestrating this biological response needs to be further explored. Cybrids (cytoplasmic hybrids) are useful cell models for studying the involvement of mitochondria in cellular processes.

Optimization of skin dose using in-vivo MOSFET dose measurements in bolus/non-bolus fraction ratio: A VMAT and a 3DCRT study.

In-phantom and in-vivo three dimensional conformal radiation therapy (3DCRT) and volumetric modulated arc therapy (VMAT) skin doses, measured with and without bolus in a female anthropomorphic phantom RANDO and in patients, were compared against treatment planning system calculated values. A thorough characterization of the metal oxide semiconductor field effect transistor measurement system was performed prior to the measurements in phantoms and patients. Patients with clinical indication for postoperative external radiotherapy were selected.

The use of needle holders in CTF guided biopsies as a dose reduction tool.

Purpose: The purpose of this study was to evaluate the efficacy of needle holders in reducing staff hand exposure during biopsies guided by computed tomography fluoroscopy (CTF), through the analysis of data acquired during a detailed monitoring study, undertaken in parallel with an ongoing optimization process to reduce hand irradiation.

Methods: Hand monitoring was performed with 11 extremity detectors, two per finger (base and tip) and one on the back of the wrist, for the left (dominant) hand, during two series of biopsies with comparable characteristics. The first series (47 biopsies) were performed with only quick-check method (QC) and occasional side-handle (SH) manipulation of the needle.

Effects of shielding on pelvic and abdominal IORT dose distributions.

Purpose: To study the impact of shielding elements in the proximity of Intra-Operative Radiation Therapy (IORT) irradiation fields, and to generate graphical and quantitative information to assist radiation oncologists in the design of optimal shielding during pelvic and abdominal IORT.

Method: An IORT system was modeled with BEAMnrc and EGS++ Monte Carlo codes. The model was validated in reference conditions by gamma index analysis against an experimental data set of different beam energies, applicator diameters, and bevel angles.

Gafchromic XR-QA2 film as a complementary dosimeter for hand-monitoring in CTF-guided biopsies.

Computed tomography fluoroscopy (CTF) is a useful imaging technique to guide biopsies, particularly lung biopsies, but it also has the potential for very high hand exposures, despite use of quick-check method and needle holders whenever feasible. Therefore, reliable monitoring is crucial to ensure the safe use of CTF. This is a challenge, because ring dosimeters monitor exposure only at the base of one finger, while the fingertips may be exposed to the highly collimated CT beam.

Erratum: Attenuation measurements show that the presence of a TachoSil surgical patch will not compromise target irradiation in intra-operative electron radiation therapy or high-dose-rate brachytherapy.

After publication of this study [1], the authors noticed that the funding was incorrectly acknowledged. The correct Acknowledgements section can be found below: “This work was partly funded by Fundação para a Ciência e Tecnologia (FCT), in the framework of the project PTDC/SAU-ENB/117631/2010, which is cofinanced by FEDER, through Programa Operacional Fatores de Competitividade - COMPETE of QREN (reference FCOMP-01-0124-FEDER-021141).”

Attenuation measurements show that the presence of a TachoSil surgical patch will not compromise target irradiation in intra-operative electron radiation therapy or high-dose-rate brachytherapy.

Background: Surgery of locally advanced and/or recurrent rectal cancer can be complemented with intra-operative electron radiation therapy (IOERT) to deliver a single dose of radiation directly to the unresectable margins, while sparing nearby sensitive organs/structures. Haemorrhages may occur and can affect the dose distribution, leading to an incorrect target irradiation. The TachoSil (TS) surgical patch, when activated, creates a fibrin clot at the surgical site to achieve haemostasis.

Characterization of geometric uncertainties of a dose calibrator during measurement of 90Y activity.

Unlabelled: The performance and measurement of (90)Y with a dose calibrator has always been a key point of several international recommendations, specifically in the case of the radiopharmaceutical (90)Y-ibritumomab tiuxetan, among other applications, used in the treatment of non-Hodgkin lymphoma. The objective of the present work was to examine in detail some important sources of geometric errors that, if neglected, can lead to an increase in uncertainty about the measured activity of this β(-) emitter radionuclide.

Methods: A CRC-15R dose calibrator was used to measure and quantify some of these sources, although the same methodology can easily be applied to any other similar equipment.

Poly (ADP-ribose) polymerase-1 deficiency does not affect ethylnitrosourea mutagenicity in liver and testis of lacZ transgenic mice.

Poly (ADP-ribose) polymerase-1 (Parp1) has been implicated in DNA base excision repair, single- and double-strand break repair pathways, as well as in cell death by apoptosis or necrosis. We used Parp1(-/-) lacZ plasmid-based transgenic mice to investigate whether Parp1 deficiency influences the in vivo mutagenic and clastogenic response to the alkylating agent N-ethyl-N-Nitrosourea (ENU) in somatic and germ-cell tissues. The comparison of the lacZ mutant frequencies (MFs) between Parp1(+/+) and Parp1(-/-) mice showed that the ablation of Parp1 does not affect the spontaneous or ENU-induced MFs in liver and testis.

Mutagenic effects of poly (ADP-ribose) polymerase-1 deficiency in transgenic mice.

Poly (ADP-ribose) polymerase-1 (Parp1) plays a central role in the maintenance of genomic integrity and has been unequivocally associated to DNA base excision repair (BER) but its involvement in double-strand break (DSB) repair pathways remains unclear. In this work, using transgenic Parp1-deficient mice harbouring the lacZ reporter gene, we provide in vivo evidence that Parp1 contributes to the prevention of deletions/insertions in testis following an alkylation insult. In response to N-Methyl-N-Nitrosurea (MNU) treatment no significant difference in the mutant frequency (MF) in the liver and testis could be attributed to Parp1 status, given that both Parp1(+/+) and Parp1(-/-) mice showed a similar significant increase in the overall MF.

Comparative analysis of the mutagenic activity of oxaliplatin and cisplatin in the Hprt gene of CHO cells.

Oxaliplatin is a platinum-derived antitumor drug that is active against cisplatin-resistant tumors and has lower overall toxicity than does cisplatin. DNA adduct formation is believed to mediate the cytotoxic activity of both compounds; however, the adducts may also be responsible for mutagenic and secondary tumorigenic activities. In this study, we have compared the mutagenicity of oxaliplatin and cisplatin in the Hprt gene of CHO-K1 cells.