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

Treatment for erectile dysfunction among older men in Northern Ireland

Background Erectile dysfunction is common among older men; however, diagnosis and treatment compared to reported prevalence is low. We aim to identify the degree to which older men are offered treatment for the condition and determine the level of unmet need within Northern Ireland (NI). Methodology Analysis of data collected using a cross‐sectional survey was conducted for men aged ≥60 years with data weighted to the NI population by age and deprivation. Respondents answered questions on sociodemographic factors, health‐related characteristics, ability to function sexually, level of sexual interest and activity, and any treatment offered to improve erections in the last 3 years. Results are presented as proportions reporting treatment receipt, with differences by respondent characteristics assessed using chi‐square tests and multivariable logistic regression. Results Among 2597 respondents, 46.5% reported erectile dysfunction. One quarter (25.8%) recalled being offered either medication, devices, or specialised services to improve erections. The offer of treatment was associated with younger age, being separated or divorced, higher number of long‐term conditions, and greater interest in sex. Of men reporting erectile dysfunction and offered medication, 28.8% found them helpful and currently use them. Conclusions As a result of not being offered treatment or not finding treatment useful, 93% of men reporting erectile dysfunction have no help with the condition. This is a likely consequence of treatment availability through the NHS in NI, but also suggests that healthcare professionals need to engage more proactively with older men, discussing sexual health routinely and following up those treated for the condition

Identifying social distress: a cross-sectional survey of social outcomes 12 to 36 months after colorectal cancer diagnosis

Purpose: To establish the prevalence and determinants of poor social outcomes after a diagnosis of colorectal cancer (CRC). Patients and Methods: All 12- to 36-month survivors of CRC (International Classification of Diseases [10th revision] codes C18 to C20) diagnosed in 2010 or 2011 and treated in the English National Health Service were identified and sent a questionnaire from their treating cancer hospital. This included the Social Difficulties Inventory, a 16-item scale of social distress (SD) comprising everyday living, money matters, and self and others subscales, plus five single items. Sociodemographic and clinical data were also collected. Analyses using descriptive statistics, 2 tests, and logistic regression models were conducted. Results: Response rate was 63.3% (21,802 of 34,467). Of the 21,802 participants, 17,830 (81.8%) completed all SD items; 2,688 (15.1%) of these 17,830 respondents were classified as experiencing SD (everyday living, 19.5%; money matters, 15.6%; self and others, 18.1%). Multivariable analysis demonstrated having three long-term conditions was the strongest predictor of SD (odds ratio [OR], 6.64; 95% CI, 5.67 to 7.77 compared with no long-term conditions), followed by unemployment (OR, 5.11; 95% CI, 4.21 to 6.20 compared with being employed), having recurrent or nontreatable disease (OR, 2.75; 95% CI, 2.49 to 3.04 compared with being in remission), and having a stoma (OR, 2.10; 95% CI, 1.86 to 2.36 compared with no stoma). Additional predictors of SD were young age (< 55 years), living in a more deprived area, nonwhite ethnicity, having advanced-stage disease, having undergone radiotherapy, and being a carer. Conclusion: Although it is reassuring a majority do not experience social difficulties, a minority reported significant SD 12 to 36 months after diagnosis of CRC. The identified clinical and social risk factors are easy to establish and should be used to target support

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

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

Health-related quality of life after treatment for bladder cancer in England

Background Little is known about quality of life after bladder cancer treatment. This common cancer is managed using treatments that can affect urinary, sexual and bowel function. Methods To understand quality of life and inform future care, the Department of Health (England) surveyed adults surviving bladder cancer 1–5 years after diagnosis. Questions related to disease status, co-existing conditions, generic health (EQ-5D), cancer-generic (Social Difficulties Inventory) and cancer-specific outcomes (Functional Assessment of Cancer Therapy—Bladder). Results In total, 673 (54%) patients responded; including 500 (74%) men and 539 (80%) with co-existing conditions. Most respondents received endoscopic treatment (60%), while 92 (14%) and 99 (15%) received radical cystectomy or radiotherapy, respectively. Questionnaire completion rates varied (51–97%). Treatment groups reported ≥1 problem using EQ-5D generic domains (59–74%). Usual activities was the most common concern. Urinary frequency was common after endoscopy (34–37%) and radiotherapy (44–50%). Certain populations were more likely to report generic, cancer-generic and cancer-specific problems; notably those with co-existing long-term conditions and those treated with radiotherapy. Conclusion The study demonstrates the importance of assessing patient-reported outcomes in this population. There is a need for larger, more in-depth studies to fully understand the challenges patients with bladder cancer face

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