3/Evaluation of set-up deviations during the irradiation of patients suffering from breast cancer treated with two different techniques

PurposeTo present results of patient positioning during routine radiotherapy for patients treated after mastectomy and to compare the inaccuracies in patient set-up for this group of patients and for the patients treated after breast conserving therapy with tangential fields.Methods and materialsIn total, the analysis comprised 56 pairs of portal and simulator films for 14 consecutive patients treated following breast conserving therapy and 98 pairs of portal and simulator films for 20 consecutive patients treated after mastectomy. For the first group the tangential field technique (TF technique) was used, for the second the inverse hockey stick technique (IHS technique). The comparison of the treatment reproducibility obtained for both groups of patients was performed in terms of systematic and random error calculated for the whole groups and by the comparison of cumulative distribution of the length of the displacement vector.ResultsIn the IHS and TF techniques for medial and lateral fields, displacement larger than 5 mm occurred in 28.3%, 15.8% and 25.4% respectively. For the IHS technique, the systematic errors for lateral and cranial-caudal direction were 1.9 and 1.7 mm respectively (1 standard deviation – SD), the random errors for lateral and cranial-caudal direction were 2.0 and 2.5 mm. For the TF technique, the systematic errors for lateral and cranial-caudal direction were 2.6 and 1.3 mm for medial field and 3.7 and 0.7 mm for lateral fields respectively, the random errors for lateral and cranial-caudal direction were 2.2 and 1.0 mm for medial field and 2.9 and 1.1 for lateral field respectively. Rotations were negligible in the HIS technique. For the TF technique the systematic component and random component amounted to about 2.0 degrees (1 SD).ConclusionsBoth the inverse hockey stick and standard tangential techniques showed good reproducibility of patients set-up with respect to cranial-caudal direction. For the TF technique, the accuracy should be improved for the medial field with respect to the ventral-dorsal direction

Effectiveness of the No action level protocol for head & neck patients – Time considerations

BackgroundThe No Action Protocol (NAL) was used to diminish the systematic set-up error. Recently, owing to the development of image registration technologies, the on-line positioning control is more often used. This method significantly reduces the CTV–PTV margin at the expense of the lengthening of a treatment session. The efficiency of NAL in decreasing the total treatment time for Head&Neck patients was investigated.MethodsResults of set-up control of 30 patients were analyzed. The set-up control was carried out on-line. For each patient and each fraction, the set-error and the time needed for making the set-up control procedure were measured. Next, retrospectively, the NAL was applied to this data. The number of initial errors (without interventions) and after NAL protocol were compared in terms of errors larger than 3 and 4 mm. The average and total time used for portal control was calculated and compared.ResultsThe number of setup errors in the posterior-anterior, inferior-superior, and right–left directions ≥3 mm and ≥4 mm were 98, 79, and 91 sessions and 44, 38 and 30 sessions out of 884 sessions. After NAL protocol the number of errors ≥3 mm and ≥4 mm decreased to 84, 57, and 39 sessions and 31, 15 and 10 sessions, respectively. The average time needed for one set-up control was 5.1 min. NAL protocol allows saving 4049 min for the whole group.ConclusionsFor locations where the random set-up errors are small, the NAL enables a very precise treatment of patients. Implementation of this protocol significantly decreases the total treatment time

Bi-Level Optimization to Enhance Intensity Modulated Radiation Therapy Planning

Intensity Modulated Radiation Therapy is an effective cancer treatment. Models based on the Generalized Equivalent Uniform Dose (gEUD) provide radiation plans with excellent planning target volume coverage and low radiation for organs at risk. However, manual adjustment of the parameters involved in gEUD is required to ensure that the plans meet patient-specific physical restrictions. This paper proposes a radiotherapy planning methodology based on bi-level optimization. We evaluated the proposed scheme in a real patient and compared the resulting irradiation plans with those prepared by clinical planners in hospital devices. The results in terms of efficiency and effectiveness are promising

The Use of Contraception and Birth Control an Outline

This article deals with the problems of contraception and birth control in Poland. An analysis of statistics regarding birth rates and the ages of mothers suggests that, in Polish society, contraception by withdrawal is a dominant practice. This method is favoured by urban women from the age of 24 and by rural women from the age of 25. As for the means of using those type of contraception, it was found that interrupted intercourse is the most prevalent means. This article also discusses the consequences of various methods of contraception and birth control for the individual, the family, the community and the Church. Finally, some suggestions for pastoral action in the examined areas are proposed

Maturity of Paternal Attitudes and Age of Fathers

The article discusses paternal attitudes in fathers belonging to different age groups. The survey was founded upon studies of such attitudes in men of two age groups, up to 25 years, and up to 35 years. It revealed that older men tended to develop excessive concentration upon the other, emotionally dependent person. Future fathers were too strongly interested in the pregnant wife, and similarly excessive emotional concentration was directed at the child as well. They took too strict care of it. The resulting ’hothouse’ conditions although able to accelerate the development could lead to lowered physical and emotional resistance. Men, both younger and older revealed great interest in the child and its life. This is an obviously positive attitude although in some cases it can evolve into prying and isolating the child from the outside influence

Dependence of tissue inhomogeneity correction factors on photon-beam energy

Introduction: Commissioning of the treatment-planning system includes the accuracy of dose calculations in the inhomogeneous absorber. Several results of measurements with regard to inhomogeneity correction factors (CFs) have been published. However, the dependence of CFs on photon-beam energy may preclude such results from being applied to the photon beams of general users. Purpose: The aim of this study was to assess the dependence of CFs on the photon-beam energy. Materials and methods: CFs were calculated by the Batho method for several slab geometries comprised of concentrations of lung tissue and water of 0.25 and 1.00 g/cm3, respectively. The CFs were calculated at 6 MV (TPR2010 = 0.67 ± k * 0.01) and 15 MV (TPR2010 = 0.76 ± k * 0.01) where k = -3, -2, -1, 0, 1, 2, 3. All calculations were performed in the region where a charged-particle equilibrium exists. Results: Changes in CFs of less than 2% were observed across the considered energy ranges. With a change in TPR20,10 of 0.01, both at 6 and 15 MV at a depth of 5 cm below the lung; and lung thicknesses of 3, 5 and 8 cm over a fi eld surface area of 10 × 10 cm2, the change in CF never exceeded 2.4%. The dependences of changes in CFs in terms of TPR20,10 were 1.74% and 1.20% for field surface areas of 5 × 5 cm2 and 20 × 20 cm2, respectively. A comparison of 42 linear accelerators (LINACs) exhibiting 6 MV and 15 MV of energy installed in Poland showed that the maximum differences in terms of TPR20,10 at 6 MV and 15 MV were 4.2% and 2.2%, respectively. Conclusion: A linear dependence of CFs on energy was observed. According to observations, the smaller the surface area of the field and deeper the point of interest below the lung, the more dependent CFs are on energy