Imaging radiation dose in breast radiotherapy by X-ray CT calibration of Cherenkov light.

Imaging Cherenkov emission during radiation therapy cancer treatments can provide a real-time, non-contact sampling of the entire dose field. The emitted Cherenkov signal generated is proportional to deposited dose, however, it is affected by attenuation from the intrinsic tissue optical properties of the patient, which in breast, ranges from primarily adipose to fibroglandular tissue. Patients being treated with whole-breast X-ray radiotherapy (n = 13) were imaged for 108 total fractions, to establish correction factors from the linear relationships between Cherenkov light and CT number (HU). This study elucidates this relationship in vivo, and a correction factor approach is used to scale each image to improve the linear correlation between Cherenkov emission intensity and dose ([Formula: see text]). This study provides a major step towards direct quantitative radiation dose imaging in humans by utilizing non-contact camera sensing of Cherenkov emission during the radiation therapy treatment.

Imaging Cherenkov photon emissions in radiotherapy with a Geiger-mode gated quanta image sensor.

The emission of Cherenkov photons from human and animal tissue can be observed during clinical x-ray or particle beam irradiation. However, imaging this weak emission with the necessary single-photon sensitivity in the clinical room is challenging because of milliwatt-level ambient room lighting and the presence of stray high-energy radiation. In this Letter, we demonstrate, to the best of our knowledge, the first Cherenkov imaging with a time-gated quanta image sensor employing a large single-photon avalanche diode (SPAD) array. Detecting single Cherenkov photons was possible with high photon avalanche gain, fast temporal gating, and moderately high ∼7% photon detection probability. Single-bit digitization and active SPAD quenching enabled stray x-ray noise suppression and photon-noise-limited imaging in a clinical environment. This type of imaging allows the knowledge of location, shape, and surface dose of the therapeutic beam radiotherapy with the stability of solid state-based detection.

Skeletal Muscle Oxygenation Measured by EPR Oximetry Using a Highly Sensitive Polymer-Encapsulated Paramagnetic Sensor.

We have incorporated LiNc-BuO, an oxygen-sensing paramagnetic material, in polydimethylsiloxane (PDMS), which is an oxygen-permeable, biocompatible, and stable polymer. We fabricated implantable and retrievable oxygen-sensing chips (40 % LiNc-BuO in PDMS) using a 20-G Teflon tubing to mold the chips into variable shapes and sizes for in vivo studies in rats. In vitro EPR measurements were used to test the chip's oxygen response. Oxygen induced linear and reproducible line broadening with increasing partial pressure (pO2). The oxygen response was similar to that of bare (unencapsulated) crystals and did not change significantly on sterilization by autoclaving. The chips were implanted in rat femoris muscle and EPR oximetry was performed repeatedly (weekly) for 12 weeks post-implantation. The measurements showed good reliability and reproducibility over the period of testing. These results demonstrated that the new formulation of OxyChip with 40 % LiNc-BuO will enable the applicability of EPR oximetry for long-term measurement of oxygen concentration in tissues and has the potential for clinical applications.

Case report of a near medical event in stereotactic radiotherapy due to improper units of measure from a treatment planning system.

PURPOSE: The authors hereby notify the Radiation Oncology community of a potentially lethal error due to improper implementation of linear units of measure in a treatment planning system. The authors report an incident in which a patient was nearly mistreated during a stereotactic radiotherapy procedure due to inappropriate reporting of stereotactic coordinates by the radiation therapy treatment planning system in units of centimeter rather than in millimeter. The authors suggest a method to detect such errors during treatment planning so they are caught and corrected prior to the patient positioning for treatment on the treatment machine. METHODS: Using pretreatment imaging, the authors found that stereotactic coordinates are reported with improper linear units by a treatment planning system. The authors have implemented a redundant, independent method of stereotactic coordinate calculation. RESULTS: Implementation of a double check of stereotactic coordinates via redundant, independent calculation is simple and accurate. Use of this technique will avoid any future error in stereotactic treatment coordinates due to improper linear units, transcription, or other similar errors. CONCLUSIONS: The authors recommend an independent double check of stereotactic treatment coordinates during the treatment planning process in order to avoid potential mistreatment of patients.

A client-centered model: discharge planning in Juvenile Justice Centres in New South Wales, Australia.

Health care delivered in Juvenile Justice Centres in New South Wales, Australia, leads to improvement in the health status of detainees while in custody but this declines on discharge and is contributed to by a breakdown in continuity of care. In an effort to halt this decline in health status, a model of interdisciplinary discharge planning is proposed to address the interface between Juvenile Justice Centres and adult correctional facilities and the community. Key features of the process are: collaboration through the development of links by establishment of a community liaison co-ordinator position; open and continuous communication between service providers; continuous involvement of detainees and their significant others; and ongoing support to detainees once discharged. Evaluation of the discharge-planning process ensures that the process is appropriate to meet the needs of this specific and diverse population of young people and supplies feedback to all service providers. The trusting relationship that is developed between detainees and registered nurses within centres leaves nurses ideally placed to co-ordinate the discharge-planning process.

Vertebrate Sprouty genes are induced by FGF signaling and can cause chondrodysplasia when overexpressed.

The Drosophila sprouty gene encodes an antagonist of FGF and EGF signaling whose expression is induced by the signaling pathways that it inhibits. Here we describe a family of vertebrate Sprouty homologs and demonstrate that the regulatory relationship with FGF pathways has been conserved. In both mouse and chick embryos, Sprouty genes are expressed in intimate association with FGF signaling centers. Gain- and loss-of-function experiments demonstrate that FGF signaling induces Sprouty gene expression in various tissues. Sprouty overexpression obtained by infecting the prospective wing territory of the chick embryo with a retrovirus containing a mouse Sprouty gene causes a reduction in limb bud outgrowth and other effects consistent with reduced FGF signaling from the apical ectodermal ridge. At later stages of development in the infected limbs there was a dramatic reduction in skeletal element length due to an inhibition of chondrocyte differentiation. The results provide evidence that vertebrate Sprouty proteins function as FGF-induced feedback inhibitors, and suggest a possible role for Sprouty genes in the pathogenesis of specific human chondrodysplasias caused by activating mutations in Fgfr3.

Locked up: researching in an unfamiliar environment.

This paper describes the personal experiences of three nurse researchers who entered a new field, one they would not normally encounter. The experiences occurred during a research project involving detainees in Juvenile Justice Centres in New South Wales, Australia. The Healthy Lifestyle Check computerized health screening program was used to seek responses regarding the detainees' health behaviours, knowledge of health services and health education needs. Physical assessment was conducted and counselling and referral was provided. The researchers' best endeavours to prepare for the field were not enough for the reality of the controlled environment, fears for personal safety and the stamina required to complete the project. The researchers' completion of the project enriched their professional lives with a sense of achievement and a new confidence in their ability to work in uncharted fields. Implications for future nursing research that incorporates fieldwork in this environment include: (i) ensuring adequate knowledge of security protocols; (ii) securing access to participants; and (iii) ensuring adequate physical assistance for fieldworkers to enter.

Healthy Lifestyle Check. A computerized health screening program.

The Healthy Lifestyle Check program is a computerized tool used to survey current health status and risk factors for potential ill health as well as to promote a healthy lifestyle. The program is an innovative teaching tool for student nurses, facilitating the integration of practice, education, and research. The program required self-report answers to questions relating to health history and current health-related behaviors with results of cholesterol, blood pressure, height, and weight assessment. Feedback to participants was provided by use of on-screen displays and printed reports containing public health messages, as well as counseling by the nurses. Results indicated that participants had not been screened for testicular, prostatic, and cervical cancers, or breast self-examination and medical checkups, and that they indulged in high levels of risk-taking behaviors such as high levels of alcohol consumption and low levels of exercise. The Healthy Lifestyle Check program is a valuable research tool that collects data and provides health information to participants, and has been used to teach nursing students the application of education and research to nursing practice.