Quality assurance of RapidArc in clinical practice using portal dosimetry.

OBJECTIVE: Quality assurance data from five centres were analysed to assess the reliability of RapidArc radiotherapy delivery in terms of machine and dosimetric performance. METHODS: A large group of patients was treated with RapidArc radiotherapy and treatment data recorded. Machine quality assurance was performed according to Ling et al (Int J Radiat Oncol Biol Phys 2008;72:575-81). In addition, treatment to a typical clinical case was delivered biweekly as a constancy check. Pre-treatment dosimetric validation of plan delivery was performed for each patient. All measurements and computations were performed at the depth of the maximum dose in water according to the GLAaS method using electronic portal imaging device measurements. Evaluation was carried out according to a gamma agreement index (GAI, the percentage of field area passing the test); the threshold dose difference was 3% and the threshold distance to agreement was 3 mm. RESULTS: A total of 275 patients (395 arcs) were included in the study. Mean delivery parameters were 31.0±20.0° (collimator angle), 4.7±0.5° s(-1) (gantry speed), 343±134 MU min(-1) (dose rate) and 1.6±1.4 min (beam-on time) for prescription doses ranging from 1.8 to 16.7 Gy/fraction. Mean deviations from the baseline dose rate and gantry speed ranged from -0.61% to 1.75%. Mean deviations from the baseline for leaf speed variation ranged from -0.73% to 0.41%. The mean GAI of repeated clinical fields was 99.2±0.2%. GAI varied from 84.7% to 100%; the mean across all patients was 97.1±2.4%. CONCLUSION: RapidArc can provide a reliable and accurate delivery of radiotherapy for a variety of clinical conditions.

Assessment of a Newark neighborhood: process and outcomes.

In 1996, the members of the St. Columba Collaboration conducted a grassroots neighborhood assessment of a Hispanic area in Newark, New Jersey. This assessment was undertaken during an era of significant political and policy change in New Jersey. As a community-driven and implemented effort, the processes, methods, and outcomes of this assessment provide lessons on community activism, political awareness, and strategic planning. Quantitative surveys were distributed to local residents as well as users of the various services provided through Collaboration programs. Ten qualitative focus groups were held among various Collaboration groups. A total of 471 surveys were returned from a door-to-door distribution and 295 surveys were returned from users of Collaboration programs. Findings from both the quantitative and qualitative components were surprisingly similar. It was striking to note that youth violence, domestic violence, crime, and lack of job skills surpassed poor housing and chronic health problems, including HIV/AIDS and drug and alcohol addiction, as the most noted neighborhood problems. Overwhelmingly, social, welfare, and environmental issues were identified as priority items in a neighborhood marked by extreme poverty, poor childhood immunization rates, high HIV/AIDS rates, and high incidence of childhood asthma. Focus group findings revealed that stressful daily life events and circumstances far overshadowed health and wellness concerns. Recommendations emanating from the St. Columba Neighborhood needs assessment included: (a) establishment of principled partnerships between the Collaboration and other regional entities to extend capacity to design and implement solutions (e.g., partnerships with other higher education institutions, health care agencies); (b) development of strategic planning processes and procedures within the Collaboration; (c) establishment of collaborative partnerships with other Hispanic community-based organizations for political activism; and (d) reorganization of the Collaboration's internal structure and functions to capitalize on opportunities for change. Significant outcomes from this process, in evidence 4 years after the 1996 neighborhood assessment, include: (a) a successful grant application to study violence against Hispanic women, (b) a research program investigating the nature and extent of clinical depression among Hispanic women, (c) establishment of a teenage pregnancy program, (d) English classes for Hispanic women seeking language skills and eventual employment, and (e) partnership extended to the New Jersey Institute of Technology.

[Use of a personal computer in contrast evaluation in magnetic resonance tomography]. / Impiego del personal computer nella valutazione del contrasto in tomografia a risonanza magnetica (RMT).

Contrast dependency in MR Tomography from several intrinsic and extrinsic parameters makes this technique versatile and sensitive; at the same time it makes more complex the image contrast evaluation and the optimized sequence choice. The approach to this problem from the viewpoint both of training and practical application becomes easier using the proposed personal computer program.

[Preliminary evaluation of the clinical use of a system for intraoperative radiotherapy with electrons (IORT)]. / Valutazioni preliminari all'impiego clinico di un sistema dedicato per radioterapia intraoperatoria con elettroni (IORT).

The preliminary evaluation of the dosimetric characteristics of a dedicated intraoperative electron beam therapy system is described (Bionix Corporation). The linear accelerator is the Varian 2100 C with electron beam energies of 6, 9, 12, 16 e 20 MeV. The isodose distribution for each of 15 available applicators (5 plane and 10 beveled) has been studied with a water phantom. The problems of the homogeneity of dose distribution, scattered and leakage radiation outside the applicators and X-ray contamination of the electron beams have been addressed, at the nominal 20 MeV energy for exemplification. The accurate knowledge of such physical and dosimetric properties are necessary for the implementation of the IORT techniques in terms of choice of the applicator size and electron beam energy for tumor coverage and dose sparing of critical organs.

[High-dose gynecologic endocavitary brachytherapy. Technical and dosimetric aspects]. / Brachiterapia endocavitaria ginecologica ad alta intensità di dose. Aspetti tecnici e dosimetrici.

The technical and dosimetric aspects are presented of high-dose intracavitary brachytherapy in gynecology. Fifty-five patients (203 insertions) were examined over two years with a remote loading Selectron HDR 60Co unit installed in a dedicated bunker. The dose to the rectal and bladder markers on AP and LL films was calculated before every irradiation, in order to allow the necessary corrections to be made. Uniform irradiation conditions were obtained at each treatment set-up for both tumoral target and bladder and rectal doses. High-dose intracavitary brachytherapy proved to be a safe, reliable and versatile method from the technical and dosimetric point of view both in the treatment of unoperated gynecological malignancies and in postoperative therapy.