The impact of the titanium cranial hardware in proton single-field uniform dose plans.

Background: Neurosurgical cranial titanium mesh and screws are commonly encountered in postoperative radiation therapy. However, only a limited number of reports are available in the context of proton therapy, resulting in a lack of consensus among the proton centers regarding the protocol for handling the hardware.

Purpose: This study is to examine the impact of the hardware in proton plans.

Treatment planning of scanned proton beams in RayStation.

The use of scanned proton beams in external beam radiation therapy has seen a rapid development over the past decade. This technique places new demands on treatment planning, as compared to conventional photon-based radiation therapy. In this article, several proton specific functions as implemented in the treatment planning system RayStation are presented.

The use of a mini-ridge filter with cyclotron-based pencil beam scanning proton therapy.

Background: Pencil beam scanning (PBS) proton therapy allows for far superior dose conformality compared with passive scattering techniques. However, one drawback of PBS is that the beam delivery time can be long, particularly when treating superficial disease. Minimizing beam delivery time is important for patient comfort and precision of treatment delivery.

Validating a double Gaussian source model for small proton fields in a commercial Monte-Carlo dose calculation engine.

Purpose: The primary fluence of a proton pencil beam exiting the accelerator is enveloped by a region of secondaries, commonly called "spray". Although small in magnitude, this spray may affect dose distributions in pencil beam scanning mode e.g.

Commissioning and validation of a novel commercial TPS for ocular proton therapy.

Background: Until today, the majority of ocular proton treatments worldwide were planned with the EYEPLAN treatment planning system (TPS). Recently, the commercial, computed tomography (CT)-based TPS for ocular proton therapy RayOcular was released, which follows the general concepts of model-based treatment planning approach in conjunction with a pencil-beam-type dose algorithm (PBA).

Purpose: To validate RayOcular with respect to two main features: accurate geometrical representation of the eye model and accuracy of its dose calculation algorithm in combination with an Ion Beam Applications (IBA) eye treatment delivery system.

Technical note: Impact of beam properties for uveal melanoma proton therapy-An in silico planning study.

Purpose: To evaluate the impact of beam quality in terms of distal fall-off (DFO, 90%-10%) and lateral penumbra (LP, 80%-20%) of single beam ocular proton therapy (OPT) and to derive resulting ideal requirements for future systems.

Methods: Nine different beam models with DFO varying between 1 and 4 mm and LP between 1 and 4 mm were created. Beam models were incorporated into the RayStation with RayOcular treatment planning system version 10 B (RaySearch Laboratories, Stockholm, Sweden).

Clinical validation of a GPU-based Monte Carlo dose engine of a commercial treatment planning system for pencil beam scanning proton therapy.

Purpose: To perform the validation of the GPU-based (Graphical Processing Unit based) proton Monte Carlo (MC) dose engine implemented in a commercial TPS (RayStation 10B) and to report final dose calculation times for clinical cases.

Materials And Methods: 440 patients treated at the Proton Therapy Center of Trento, Italy, between 2018 and 2019 were selected for this study. 636 approved plans with 3361 beams computed with the clinically implemented CPU-MC dose engine (version 4.

Experiments and Monte Carlo simulations on multiple Coulomb scattering of protons.

Background And Purpose: Monte Carlo simulations as well as analytical computations of proton transport in material media require accurate values of multiple Coulomb scattering (MCS) angles. High-quality experimental data on MCS angles in the energy range for proton therapy are, however, sparse. In this work, MCS modeling in proton transport was evaluated employing an experimental method to measure these angles on a medical proton beamline in clinically relevant materials.

Validation and practical implementation of seated position radiotherapy in a commercial TPS for proton therapy.

Purpose: This work aims to validate new 6D couch features and their implementation for seated radiotherapy in RayStation (RS) treatment planning system (TPS).

Materials And Methods: In RS TPS, new 6D couch features are (i) chair support device, (ii) patient treatment option of "Sitting: face towards the front of the chair", and (iii) patient support pitch and roll capabilities. The validation of pitch and roll was performed by comparing TPS generated DRRs with planar x-rays.

Validation of the RayStation Monte Carlo dose calculation algorithm using a realistic lung phantom.

Purpose: Our purposes are to compare the accuracy of RaySearch's analytical pencil beam (APB) and Monte Carlo (MC) algorithms for clinical proton therapy and to present clinical validation data using a novel animal tissue lung phantom.

Methods: We constructed a realistic lung phantom composed of a rack of lamb resting on a stack of rectangular natural cork slabs simulating lung tissue. The tumor was simulated using 70% lean ground lamb meat inserted in a spherical hole with diameter 40 ± 5 mm carved into the cork slabs.

Validation of the RayStation Monte Carlo dose calculation algorithm using realistic animal tissue phantoms.

Purpose: The aim of this study is to validate the RayStation Monte Carlo (MC) dose algorithm using animal tissue neck phantoms and a water breast phantom.

Methods: Three anthropomorphic phantoms were used in a clinical setting to test the RayStation MC dose algorithm. We used two real animal necks that were cut to a workable shape while frozen and then thawed before being CT scanned.

Clinical examination of proton pencil beam scanning on a moving anthropomorphic lung phantom.

The objective of this study was to examine the use of proton pencil beam scanning for the treatment of moving lung tumors. A single-field uniform dose proton pencil beam scanning (PBS) plan was generated for the standard thorax phantom designed by the Imaging and Radiation Oncology Core (IROC) Houston QA Center. Robust optimization, including range and setup uncertainties as well as volumetric repainting, was used for the plan.

Dosimetric evaluation of a commercial proton spot scanning Monte-Carlo dose algorithm: comparisons against measurements and simulations.

RaySearch Americas Inc. (NY) has introduced a commercial Monte Carlo dose algorithm (RS-MC) for routine clinical use in proton spot scanning. In this report, we provide a validation of this algorithm against phantom measurements and simulations in the GATE software package.

Complications after colonoscopy and surgery in a population-based colorectal cancer screening programme.

Objectives: To report complications after colonoscopy and surgery in patients with neoplasia detected through a population based colorectal cancer (CRC) screening programme in the capital region of Sweden.

Methods: Patients who after a positive FOBT screening result underwent colonoscopy from 1 January 2008 to 30 June 2012 were included. Mortality and complications within 30 days after colonoscopy or subsequent surgery were identified through national registers, and complications were assessed through review of medical charts.

Localized interaction of single porphyrin molecules with oxygen vacancies on TiO2(110).

Alterations in the electronic structure of adsorbed zinc(II) etioporphyrin I (ZnEtio) through interaction with bridging oxygen vacancies on TiO(2)(110) are studied by scanning tunneling microscopy and spectroscopy at cryogenic temperatures under ultrahigh vacuum (UHV) conditions. Upon lateral manipulation of ZnEtio molecules above surface oxygen vacancies, the highest occupied molecular orbital shifts away from the Fermi level. The magnitude of the shift rapidly decreases with increasing distance of the molecule from the vacancy, indicating a highly localized interaction.

Predicting lymph node metastases in early rectal cancer.

Aim: In this population-based study, the aim was to investigate risk factors for lymph node metastases and to construct a risk stratification index with relevance for pre-operative planning in T1 and T2 rectal cancers.

Methods: Data were retrieved from The Swedish Rectal Cancer Register, a mandatory, national, prospectively collected data base. All T1 and T2 rectal cancers treated with abdominal resection surgery without neo-adjuvant or adjuvant radio-chemotherapy from 2007 to 2010 were analysed.

Local insufflation of warm humidified CO₂increases open wound and core temperature during open colon surgery: a randomized clinical trial.

Background: The open surgical wound is exposed to cold and dry ambient air resulting in heat loss through radiation, evaporation, and convection. Also, general and neuraxial anesthesia decrease the patient's core temperature. Despite routine preventive measures mild intraoperative hypothermia is still common and contributes to postoperative morbidity and mortality.

Intraoperative local insufflation of warmed humidified CO₂ increases open wound and core temperatures: a randomized clinical trial.

Background: The open surgical wound is exposed to cold dry ambient air, resulting in substantial heat loss through radiation, evaporation, and convection. At the same time, anesthesia decreases the patient's core temperature. Despite preventive measures, mild intraoperative hypothermia has been associated with postoperative morbidity.

Bowel obstruction after laparoscopic and open colon resection for cancer: results of 5 years of follow-up in a randomized trial.

Background: Postoperative bowel obstruction caused by intra-abdominal adhesions occurs after all types of abdominal surgery. It has been suggested that the laparoscopic technique should reduce the risk for adhesion formation and thus for postoperative bowel obstruction. This study was designed to compare the incidence of bowel obstruction in a randomized trial where laparoscopic and open resection for colon cancer was compared.

Common variants in human CRC genes as low-risk alleles.

The genetic susceptibility to colorectal cancer (CRC) has been estimated to be around 35% and yet high-penetrance germline mutations found so far explain less than 5% of all cases. Much of the remaining variations could be due to the co-inheritance of multiple low penetrant variants. The identification of all the susceptibility alleles could have public health relevance in the near future.

PepT1 oligopeptide transporter (SLC15A1) gene polymorphism in inflammatory bowel disease.

Background: Human polymorphisms affecting gut epithelial barrier and interactions with bacteria predispose to the inflammatory bowel diseases (IBD) Crohn's disease (CD) and ulcerative colitis (UC). The intestinal transporter PepT1, encoded by the SLC15A1 gene, mediates intracellular uptake of bacterial products that can induce inflammation and NF-kappaB activation upon binding to NOD2, a protein often mutated in CD. Hence, we tested SLC15A1 polymorphisms for association with IBD.

Analysis of patient selection and external validity in the Swedish contribution to the COLOR trial.

Objective: The colon cancer laparoscopic or open resection (COLOR) trial is an international, randomised controlled trial comparing outcomes of open and laparoscopic surgery for colon cancer. The main purpose of this study was to determine representability by comparing included and nonincluded patients in the participating Swedish centres.

Design: At eight centres, which included 391 of the 422 Swedish patients, a local database search was performed to identify retrospectively all patients (n = 2,384) who underwent surgery for colon cancer during the inclusion period, and data was retrieved from medical records.

Correlation effects in wave function mapping of molecular beam epitaxy grown quantum dots.

We investigate correlation effects in the regime of a few electrons in uncapped InAs quantum dots by tunneling spectroscopy and wave function (WF) mapping at high tunneling currents where electron-electron interactions become relevant. Four clearly resolved states are found, whose approximate symmetries are roughly s and p, in order of increasing energy. Because the major axes of the p-like states coincide, the WF sequence is inconsistent with the imaging of independent-electron orbitals.

Randomized trial of health-related quality of life after open and laparoscopic surgery for colon cancer.

Background: Randomized controlled trials (RCTs) have reported improved or unchanged three-year survival following laparoscopic colon resection (LCR) for colon cancer compared with that following open resection (OCR). The aim of this study was to determine health-related quality of life (HRQL) in patients randomized to laparoscopic or open resection for colon cancer.

Methods: In total, 285 patients (130 LCR, 155 OCR) from seven Swedish centers were included.

Principles for the design of the economic evaluation of COLOR II: an international clinical trial in surgery comparing laparoscopic and open surgery in rectal cancer.

Objectives: The objective is to describe the principles for the design of the economic evaluation of COLOR II, a randomized, multi-country study comparing laparoscopic and open surgery for rectal cancer.

Methods: By using the experiences gained in a recent economic evaluation in colon cancer, where the same surgical techniques were compared, we could improve the method for identifying and measuring resource use items and also accommodate the use of data from the global study population.

Results: In the design of the study, the uncertainty in the resource-use variables was reduced by considering (i) what aspects drive each variable, (ii) what resource use is related to the intervention, (iii) how data from different countries affects the variable.