Quantitative Cherenkov emission spectroscopy for tissue oxygenation assessment

Measurements of Cherenkov emission in tissue during radiation therapy are shown to enable estimation of hemoglobin oxygen saturation non-invasively, through spectral fitting of the spontaneous emissions from the treated tissue. Tissue oxygenation plays a critical role in the efficacy of radiation therapy to kill tumor tissue. Yet in-vivo measurement of this has remained elusive in routine use because of the complexity of oxygen measurement techniques. There is a spectrally broad emission of Cherenkov light that is induced during the time of irradiation, and as this travels through tissue from the point of the radiation deposition, the tissue absorption and scatter impart spectral changes. These changes can be quantified by diffuse spectral fitting of the signal. Thus Cherenkov emission spectroscopy is demonstrated for the first time quantitatively in vitro and qualitatively in vivo, and has potential for real-time online tracking of tissue oxygen during radiation therapy when fully characterized and developed. (C) 2012 Optical Society of Americ

A GAMOS Plug-In for GEANT4 Based Monte Carlo Simulation of Radiation-Induced Light Transport in Biological Media

We describe a tissue optics plug-in that interfaces with the GEANT4/GAMOS Monte Carlo (MC) architecture, providing a means of simulating radiation-induced light transport in biological media for the first time. Specifically, we focus on the simulation of light transport due to the Čerenkov effect (light emission from charged particle\u27s traveling faster than the local speed of light in a given medium), a phenomenon which requires accurate modeling of both the high energy particle and subsequent optical photon transport, a dynamic coupled process that is not well-described by any current MC framework. The results of validation simulations show excellent agreement with currently employed biomedical optics MC codes, [i.e., Monte Carlo for Multi-Layered media (MCML), Mesh-based Monte Carlo (MMC), and diffusion theory], and examples relevant to recent studies into detection of Čerenkov light from an external radiation beam or radionuclide are presented. While the work presented within this paper focuses on radiation-induced light transport, the core features and robust flexibility of the plug-in modified package make it also extensible to more conventional biomedical optics simulations. The plug-in, user guide, example files, as well as the necessary files to reproduce the validation simulations described within this paper are available online at http://www.dartmouth.edu/optmed/research-projects/monte-carlo-software

Real-time in vivo Cherenkoscopy Imaging During External Beam Radiation Therapy

Cherenkov radiation is induced when charged particles travel through dielectric media (such as biological tissue) faster than the speed of light through that medium. Detection of this radiation or excited luminescence during megavoltage external beam radiotherapy (EBRT) can allow emergence of a new approach to superficial dose estimation, functional imaging, and quality assurance for radiation therapy dosimetry. In this letter, the first in vivo Cherenkov images of a real-time Cherenkoscopy during EBRT are presented. The imaging system consisted of a time-gated intensified charge coupled device (ICCD) coupled with a commercial lens. The ICCD was synchronized to the linear accelerator to detect Cherenkov photons only during the 3.25-μs radiation bursts. Images of a tissue phantom under irradiation show that the intensity of Cherenkov emission is directly proportional to radiation dose, and images can be acquired at 4.7  frames/s with SNR\u3c30 . Cherenkoscopy was obtained from the superficial regions of a canine oral tumor during planned, Institutional Animal Care and Use Committee approved, conventional (therapeutically appropriate) EBRT irradiation. Coregistration between photography and Cherenkoscopy validated that Cherenkov photons were detected from the planned treatment region. Real-time images correctly monitored the beam field changes corresponding to the planned dynamic wedge movement, with accurate extent of overall beam field, and expected cold and hot regions

Using the framework method for the analysis of qualitative dyadic data in health research

There are an increasing number of qualitative studies which focus on the dyad (couples, families, caregivers–patients, health care professionals–patients). However, there is limited literature regarding qualitative methodology for dyadic analysis when members of the couple have been interviewed separately. The aim of this article is to share the knowledge we gained from undertaking a novel approach to dyadic analysis. We used an adapted version of the Framework method on data gathered in a study exploring the impact of prostate cancer on younger men and their partners. In this article, we examine and reflect on the challenges of this type of analysis and describe how we analyzed the interview data from a dyadic point of view, to share what we learned in the process

The challenges on the family unit faced by younger couples affected by prostate cancer: A qualitative study

Objective. The number of younger men being diagnosed with Prostate cancer (PCa), (aged ≤ 65) is increasing. It is recognised that PCa and treatment side effects can have a significant impact on quality of life. This study explores the challenges faced by younger couples affected by PCa with dependent children (under 18 years) or young adults (18-29 years) in their families. Methods. Twenty-three men with PCa and their partners were interviewed (separately) by telephone. Participants were recruited from respondents to the Life After Prostate Cancer Diagnosis (LAPCD) national survey. Men were three to five years post-diagnosis, and following a range of treatment pathways. Data were analysed using the Framework approach. Results. Younger couples affected by PCa felt challenged by issues relating to their parental role and the dynamics within the family. Five main themes emerged: difficult conversations about PCa diagnosis; parental perceptions of the impact of diagnosis on children; parental responses to the impact of PCa on the family; shielding, coping and normalising strategies; and levels of support. Conclusions. A diagnosis of PCa can cause significant disruption to the family unit and the quality of life of its members. Support programmes offering guidance to children/young adults affected by PCa in their family, and addressing the concerns of parents may help families to better adapt. Encouraging clinical professionals to initiate conversations with younger couples about their children may be a way forward in directing appropriate support. Further research is needed to elucidate appropriate, effective supportive interventions

Oxygen Tomography by Čerenkov-Excited Phosphorescence during External Beam Irradiation

The efficacy of radiation therapy depends strongly on tumor oxygenation during irradiation. However, current techniques to measure this parameter in vivo do not facilitate routine monitoring in patients. Herein, we demonstrate a noninvasive method for tomographic imaging of oxygen partial pressure (pO2 ) in deep tissue using the phosphorescence decay of an oxygen-sensitive probe excited by Čerenkov radiation induced by external beam radiotherapy. Tissue-simulating scattering phantoms (60 mm diameter with a 20 mm anomaly) containing platinum(II)-G4 (PtG4), a dendritic porphyrin-based phosphor, whose phosphorescence is quenched in the presence of oxygen, were irradiated with a clinical linear accelerator. The emitted phosphorescence was measured at various positions on the phantom boundary using a spectrograph coupled to an intensified charge-coupled device (ICCD). At each position, PtG4 phosphorescence decay curves were measured by synchronizing the ICCD to the linear accelerator pulses. Tomographic images of phosphorescence yield and lifetime were recovered for phantoms with homogenous PtG4 concentrations and heterogeneous pO2 . Since PtG4 lifetime is strongly and predictably dependent on pO 2 through the Stern-Volmer relationship, tomographic images of pO 2 were also reported, and showed excellent agreement with independent oxygenation measurements. Translating this approach to the clinic could facilitate direct sensing of pO2 during radiotherapy

Decision regret in men living with and beyond nonmetastatic prostate cancer in the United Kingdom: A population‐based patient‐reported outcome study

Objective: Clinical options for managing nonmetastatic prostate cancer (PCa) vary. Each option has side effects associated with it, leading to difficulty in decision‐making. This study aimed to assess the relationship between patient involvement in treatment decision‐making and subsequent decision regret (DR), and quantify the impact of health‐related quality of life (HRQL) outcomes on DR. Methods: Men living in the United Kingdom, 18 to 42 months after diagnosis of PCa, were identified from cancer registration data and sent a questionnaire. Measures included the Decision Regret Scale (DRS), Expanded Prostate cancer Index Composite short form (EPIC‐26), EQ‐5D‐5L, and an item on involvement in treatment decision‐making. Multivariable ordinal regression was utilized, with DR categorized as none, mild, or moderate/severe regret. Results: A total of 17 193 men with stage I‐III PCa completed the DRS: 36.6% reported no regret, 43.3% mild regret, and 20.0% moderate/severe regret. The odds of reporting DR were greater if men indicated their views were not taken into account odds ratio ([OR] = 6.42, 95% CI: 5.39‐7.64) or were involved “to some extent” in decision‐making (OR = 4.63, 95% CI: 4.27‐5.02), compared with men who were “definitely” involved. After adjustment, including for involvement, men reporting moderate/big problems with urinary, bowel, or sexual function were more likely to experience regret compared with men with no/small problems. Better HRQL scores were associated with lower levels of DR. Conclusions: This large‐scale study demonstrates the benefit of patient involvement in treatment decision‐making for nonmetastatic PCa. However, men experiencing side effects and poorer HRQL report greater DR. Promoting engagement in clinical decision‐making represents good practice and may reduce the risk of subsequent regret

The Paradox of Power in CSR: A Case Study on Implementation

Purpose Although current literature assumes positive outcomes for stakeholders resulting from an increase in power associated with CSR, this research suggests that this increase can lead to conflict within organizations, resulting in almost complete inactivity on CSR. Methods A single in-depth case study, focusing on power as an embedded concept. Results Empirical evidence is used to demonstrate how some actors use CSR to improve their own positions within an organization. Resource dependence theory is used to highlight why this may be a more significant concern for CSR. Conclusions Increasing power for CSR has the potential to offer actors associated with it increased personal power, and thus can attract opportunistic actors with little interest in realizing the benefits of CSR for the company and its stakeholders. Thus power can be an impediment to furthering CSR strategy and activities at the individual and organizational level

Approaches to working with children and families: a review of the evidence for practice

This paper explores a range of approaches to working with children and families within Children's Services and Children's Social Care, in a UK local authority context. There are a variety of established approaches, supported by different concepts and theories. Given the substantial recent and developing changes in the political, social and economic context for supporting families in need, collating academic and practical evidence to inform both theory and decision making is vital. The article has a practice focus for Children's Services, but it is also relevant and has implications for a much wider readership. Evidence was gathered through a purposive and rapid review, and aggregated with practice evidence from various sources. An array of issues is considered relating to the context, theory, application, implementation and evaluation of taking one or several approaches. Overall, there is a very limited evidentiary basis, either from research or local authority practice, for adopting any one, wholesale approach to working with children and families in a local authority context over another, but there is emerging evidence of the benefits that certain models and approaches could have, and anecdotally the decision to adopt one formal model appears to be increasing