External photon radiation treatment for prostate cancer: Uncomplicated and cancer-free control probability assessment of 36 plans.

PURPOSE: To perform a systematic and thorough assessment, using the Uncomplicated and Cancer-Free Control Probability (UCFCP) function, of a broad range of photon prostate cancer RT treatments, on the same scenario (a unique pelvic CT set). UCFCP considers, together with the probabilities of local tumour control (TCP) and deterministic (late) sequelae (NTCP), the second primary cancer risk (SPCR) due to photon and neutron peripheral doses. METHODS AND MATERIALS: Thirty-six radiotherapy plans were produced for the same CT. 6, 10, 15 and 18 MV 3DCRT, IMRT and VMAT (77.4 Gy in 43 fractions) and 6 and 10 MV SBRT (36.25 Gy in 5 fractions with flattened and FFF beams) for Elekta, Siemens and Varian Linacs plans were included. DVH and peripheral organ dosimetry were used to compute TCP, NTCP, and SPCR (the competition and LNT models) for further plan ranking. RESULTS: Biological models (and parameters) used predicted an outcome which is in agreement with epidemiological findings. SBRT plans showed the lowest SPCR and a below average NTCPrectal. High energy plans did not rank worse than the low energy ones. Intensity modulated plans were ranked above the 3D conformal techniques. CONCLUSIONS: According to UCFCP, the best plans were the10 MV SBRTs. SPCR rates were low and did not show a substantial impact on plan ranking. High energy intensity-modulated plans did not increase in excess the average of SPCR. Even more, they ranked among the best, provided that MU were efficiently managed.

10-MV SBRT FFF IRRADIATION TECHNIQUE IS ASSOCIATED TO THE LOWEST PERIPHERAL DOSE: THE OUTCOME OF 142 TREATMENT PLANS FOR THE 10 MOST COMMON TUMOUR LOCATIONS.

There is a growing interest in the combined use of Stereotactic Body Radiation Therapy (SBRT) with Flattening Filter Free (FFF) due to the high local control rates and reduced treatment times, compared to conventionally fractionated treatments. It has been suggested that they may also provide a better radiation protection to radiotherapy patients as a consequence of the expected decrease in peripheral doses. This work aims to determine this reduction in unattended out-of-field regions, where no CT information is available but an important percentage of second primary cancers occur. For that purpose, ten different cases suitable for SBRT were chosen. Thus, 142 different treatment plans including SBRT, as well as 3D-CRT, IMRT and VMAT (with standard fractionation) in low and high energies for Varian (FF and FFF), Siemens and Elekta machines were created. Then, photon and neutron peripheral dose in 14 organs were assessed and compared using two analytical models. For the prostate case, uncomplicated and cancer free control probability estimation was also carried out. As a general behavior, SBRT plans led to the lowest peripheral doses followed by 3D-CRT, VMAT and IMRT, in this order. Unflattened beams proved to be the most effective in reducing peripheral doses, especially for 10 MV. The obtained results suggest that FFF beams for SBRT with 10 MV represent the best compromise between dose delivery efficiency and peripheral dose reduction.

[Description of the "new" intensive care unit of the Valladolid Río Hortega Hospital]. / Descripción de la "nueva" unidad de cuidados intensivos del Hospital Río Hortega de Valladolid.

The unit described herein forms part of the Rio Hortega Hospital in Valladolid (Spain) and is situated on the third floor. The building houses several medical and surgical specialities and has been renovated several times; the latest renovations have involved technical and structural renovation of the Intensive Care Unit. The new intensive care unit was inaugurated in February 1998 due to new technical and medical requirements. The aim of improving medical care and the degree of satisfaction among patients and their families has been achieved and the work environment is more congenial and peaceful. The unit is composed of two areas: the multipurpose intensive care unit and the cardiology intensive care unit, edowed with the same monitoring system and apparatus specific to each. Moreover, the unit is composed of an administration area, storerooms and an area for common services (a room for the cleaning of material, waste disposal, lavatories, etc.). The medical team is composed of (a) medical staff-seven staff doctors and five residents; (b) nursing staff: 18 nurses and 13 nurse's aides in the multipurpose Intensive Care Unit; 13 nurses and 8 nurse's aides in the cardiology intensive care unit: one supervisor common to both units; administrative staff: one secretary; one security guard and one cleaner. The distribution of nursing work depends on workload reflected in the patient's daily chart, protocols, nursing care plans and follow-up sheets for the nursing team. Visiting hours are divided between the morning and afternoon and information is given to the patient's relatives by the doctor before the visit. The hospital has three catholic priests who periodically visit the patients. We also try to help when the patients profess other religious faith. The type of patients who are cared for in the unit as well as their distribution according to condition, severity, death, etc, is shown in figures: the data correspond to the period from January 1 1998 to August 1 1999.