C Kestler | PubMed Health

PubMed1987

Technique for external beam treatment for mesothelioma.

A combined photon-electron beam treatment for diffuse pleural mesothelioma is discussed in this paper. The technique consists of parallel opposed 10 MV X rays prescribed to 4250 cGy using customized blocks to shield the lung. The pleura is then boosted with electrons to a dose of 3600 cGy. The combination yields a TDF of 74 ret to the pleura. As discussed in an earlier paper, this treatment method when combined with subtotal pleurectomy and I-125 implantation leads to improved survivals with minimal complications. The details of this 3-dimensional radiation treatment method were not described in detail. To improve target coverage and local control, the technique has been modified. CT is now used along with simulation plane films to define the entire pleural surface. The target volume has also been extended from the dome to the base of this diaphragm. These changes have led to improved pleural dose distributions; by blocking the liver or stomach, and boosting the crus of the diaphragm with electrons, there is little added morbidity. As is demonstrated by dose volume histograms, we have been able to deliver 4250 cGy +/- 10% to most of the pleura with 1/3 of the lung parenchyma receiving less than 2100 cGy.

Brachytherapy↗

PubMed1985

Clinical experience with a computerized record and verify system.

To improve the quality of patient care by detecting and preventing many types of treatment mistakes, we have implemented a computerized system for recording and verifying external beam radiation treatments on our therapy machines. It inhibits the radiation beam if treatment machine settings do not agree with prescribed values to within maximum permissible deviations (tolerances). The tolerances are determined from experience and adjusted when necessary to make the system more effective and less susceptible to "false alarms." The system uses a common data base for all treatment machines. As a result, it permits statistical analysis and generation of reports based on data encompassing the entire patient population as well as verification of treatments of patients transferred from one machine to another. Reports of verification failures reveal patterns of mistakes. Knowing these, attempts can be made to reduce the frequency of verification failures. "Significant" mistakes that were prevented are extracted by treatment planning personnel from these reports. Analysis of data indicates a rate of approximately 150 "significant" mistakes detected and prevented per machine per year, representing 1.0% of all fields treated. We present and discuss our experiences with the system and with the frequency, patterns, and significance of verification failures. We selected a few of the patients for whose treatments significant set-up mistakes were made, and were detected and prevented by the Record and Verify System. We include discussions of the overall effect these mistakes would have had on dose distribution had they not been prevented.

Adult↗