Development of a 3-D visible limiter imaging system for the HSX stellarator

A visible camera diagnostic has been developed to study the Helically Symmetric eXperiment (HSX) limiter plasma interaction. A straight line view from the camera location to the limiter was not possible due to the complex 3D stellarator geometry of HSX, so it was necessary to insert a mirror/lens system into the plasma edge. A custom support structure for this optical system tailored to the HSX geometry was designed and installed. This system holds the optics tube assembly at the required angle for the desired view to both minimize system stress and facilitate robust and repeatable camera positioning. The camera system has been absolutely calibrated and using H_α and C-III filters can provide hydrogen and carbon photon fluxes, which through an S/XB coefficient can be converted into particle fluxes. The resulting measurements have been used to obtain the characteristic penetration length of hydrogen and C-III species. The hydrogen λ_iz value shows reasonable agreement with the value predicted by a 1D penetration length calculation.

Current radiosurgery practice: results of an ASTRO survey. Task Force on Stereotactic Radiosurgery, American Society for Therapeutic Radiology and Oncology

PURPOSE

Although there is increasing interest in radiosurgery, little quantitative data regarding current patterns of radiosurgery practice are available. We developed a radiosurgery questionnaire to obtain information on radiosurgery practice.

METHODS AND MATERIALS

We distributed the questionnaire to the entire membership of the American Society of Therapeutic Radiology and Oncology in early 1993. Responses were obtained from 74 facilities that practice radiosurgery, corresponding to over 6000 treatments carried out since 1983 by 135 radiation oncologists and 130 physicists.

RESULTS

Most respondents were found to work within a multidisciplinary team, consisting of the following specialists (average hours devoted per patient on day of treatment in parentheses): radiation oncologist (3.8), neurosurgeon (3.2), physicist (6.1), radiologist (0.7), nurse (2.7), other (3.0). On average, neurosurgeons and nurses who perform Gamma Knife radiosurgery devote significantly more time-per-patient on the day of treatment than their peers who perform linac radiosurgery. On average, less experienced radiation oncologists and physicists (< or = 24 months experience, or < or = 50 patients treated) devote significantly more time-per-patient on the day of treatment than their more experienced peers. Although there are many more linac radiosurgery facilities than Gamma Knife facilities, on average the number of patients treated per month per facility is significantly larger at the latter. On average, follow-up responsibilities are nearly equally shared by radiation oncologists and neurosurgeons, except at Gamma Knife facilities, where neurosurgeons assume a larger percentage of follow-up responsibility. The percentages of patients treated at linac facilities for metastases or primary CNS malignancy are larger than the corresponding percentages at Gamma Knife facilities; the opposite is true for arteriovenous malformation, acoustic neuroma, and meningioma.

CONCLUSION

Current radiosurgery practice usually involves a team approach, with participation of specialists from radiation oncology, neurosurgery, physics, radiology, and nursing. The average number of M.D. and Ph.D. hours required per treatment on the day of radiosurgery is high.

Obtaining parental perceptions of the quality of services for children with special health needs

Analyzed responses from 295 parents across two service delivery sites to identify specific factors of satisfaction. Although General Satisfaction accounted for most variance, Clarity of Communication, Preappointment Wait and Information, and Clinic Efficiency were also identified as factors. Results are discussed in the context of a collaborative relationship between parents and providers. A shortened questionnaire that efficiently taps these areas of satisfaction is appended.

Facilitating play in hospitalized handicapped children: the design of a therapeutic play environment

The development of a play environment is described, including a play structure that was designed to facilitate symbolic play in hospitalized, handicapped children. The effect of the structure on play was tested on handicapped children aged 2 to 13 years who were verbal and able to use at least one hand. Twenty-five pretest and 25 posttest observations were conducted and data were coded into play and nonplay categories. Results indicated decline in aimless wandering and nonplay activities, with a concomitant increase in both partial and symbolic play. The implications for play among hospitalized, handicapped children are discussed.

Postoperative radiation as adjuvant treatment for carcinoma of the oral cavity, larynx, and pharynx: preliminary report of a prospective randomized trial

A prospective randomized trial was performed in patients with advanced squamous cell carcinomas (SCC) of the oral cavity, larynx, and pharynx to examine the effect of adjuvant postoperative radiation therapy on locoregional recurrence and survival following "curative" resection. Fifty-one patients with stage III or IV SCC treated from 1981 through 1984 were randomized to receive either surgery alone (n = 27) or surgery with postoperative radiation (n = 24). Five patients were excluded from the study after randomization because of ineligibility or protocol violations. Overall recurrence rates of 55.6% and 36.8% were noted in the surgery and surgery with adjuvant radiotherapy arms, respectively (p = NS). This trend towards a higher recurrence rate in the surgery only arm was in part due to the development of lymph node metastases in the contralateral, nonoperated neck. Thus far, no significant differences in either locoregional or overall survival have been noted between the two treatment arms. In this preliminary analysis, adjuvant postoperative radiotherapy does not appear to improve disease-free or overall survival.

Progressive postnatal subependymal necrosis in an infant with congenital cytomegalovirus infection

An infant with congenital cytomegalovirus infection developed subependymal cysts postnatally. This patient provides further support for the concept that congenitally-infected infants occasionally have postnatal progression of central nervous system lesions.