Total skin electron irradiation (TSEI) has been employed as one of the methods of mycosis fungoides treatment since the mid-twentieth century. In order to improve the effects and limit the complications following radiotherapy, a number of varieties of the TSEI method, frequently differing in the...

Plan complexity and robustness are two essential aspects of treatment plan quality but there is a great variability in their management in clinical practice. This study reports the results of the 2020 ESTRO survey on plan complexity and robustness to identify needs and guide future discussions and consensus. A survey was distributed online to ESTRO members. Plan complexity was defined as the modulation of machine parameters and increased uncertainty in dose calculation and delivery. Robustness was defined as a dose distribution's sensitivity towards errors stemming from treatment uncertainties, patient setup, or anatomical changes. A total of 126 radiotherapy centres from 33 countries participated, 95 of them (75%) from Europe and Central Asia. The majority controlled and evaluated plan complexity using monitor units (56 centres) and aperture shapes (38 centres). To control robustness, 98 (97% of question responses) photon and 5 (50%) proton centres used PTV margins for plan optimization while 75 (94%) and 5 (50%), respectively, used margins for plan evaluation. Seventeen (21%) photon and 8 (80%) proton centres used robust optimisation, while 10 (13%) and 8 (80%), respectively, used robust evaluation. Primary uncertainties considered were patient setup (photons and protons) and range calculation uncertainties (protons). Participants expressed the need for improved commercial tools to control and evaluate plan complexity and robustness. Clinical implementation of methods to control and evaluate plan complexity and robustness is very heterogeneous. Better tools are needed to manage complexity and robustness in treatment planning systems. International guidelines may promote harmonization.

Radiotherapy treatment requires delivering high homogenous dose to target volume while sparing organs at risk. That is why accurate patient positioning is one of the most important steps during the treatment process. It reduces set-up errors which have a strong influence on the doses given to the target and surrounding tissues. The aim of this study was to investigate the efficiency of combining bony anatomy and soft tissue imaging position correction strategies for patients with prostate cancer. The study based on pre-treatment position verification results determined for 10 patients using kV images and CBCT match. At the same patients' position, two orthogonal kV images and set of CT scans were acquired. Both verification methods gave the information about patients' position changes in vertical, longitudinal and lateral directions. For 93 verifications, the mean values of kV shifts in vertical, longitudinal and lateral directions equaled: -0.11 ± 0.54 cm, 0.26 ± 0.38 cm and -0.06 ± 0.47 cm, respectively. The same values achieved for CBCT matching equaled: 0.07 ± 0.62 cm, 0.22 ± 0.36 cm and -0.02 ± 0.45 cm. Statistically significant changes between the values of shifts received during the first week of treatment and the rest time of the irradiation process were found for 2 patients in the lateral direction and 2 patients in vertical direction among kV results and for 3 patients in the longitudinal direction among CBCT results. A significant difference between kV and CBCT match results was found in the vertical direction. In clinical practice, CBCT combined with kV or even portal imaging improves precision and effectiveness of prostate cancer treatment accuracy.

SummaryBackgroundThe aim of total skin electron irradiation in the therapy of mycosis fungoides is to obtain total or partial remission of the disease while concurrently lowering the toxicity level. Total skin electron radiotherapy should fulfill the EORTC requirements from the year 2002.AimThe aim of this work is to present the rotary dual method for total skin electron irradiation used in the Great Poland Cancer Centre including its specific technical and physical aspects. These aspects include the parameters and conditions for the treatment (geometrical conditions of the technique, homogeneity of the dose, patient's positioning, additional fields and the method of dose fractionation), the absolute dosimetry (parameters and functions characterizing the electron irradiation beam used in the rotary dual method of the rotary dual method of the total skin electron irradiation) and in-vivo dosimetry conducted during the therapy with rotary dual fields, which allowed to control the dose distribution and to indicate additional skin areas, which should be irradiated with local fields.Materials/MethodsThe rotary dual method of the Total Skin Electron Irradiation proposed by the author, is based on the combination of the two most frequently used methods: 1) six dual fields’ method and 2) rotary method. The original, calculation algorithm elaborated by the author was based on the two dimensional algorithm proposed by Podgorsak et al.ResultsThe new algorithm, proposed by the author takes into the changes in doses along the vertical and horizontal axis of the object. Moreover the elliptical; shape of the object proposed by the author, is more approximated to the shape of the patient than the cylindrical object proposed by Podgorsak et al.DiscussionParameters used by authors: nominal energy – 6 MeV, mean energy at the skin surface – 2.8 MeV, values of the PDD (at the skin surface – 100%, at the 4 mm – 83.6% and at the 20 mm – 1.8%), SSD – 300 cm, field size equal to 230 cm by 115 cm, fraction dose – 1.5Gy, total time of treatment from 6 to 7 weeks were compatibility with EORTC recommendations.The elaboration of the rotary – dual method of total skin electron irradiation allowed to reduce SSD distance compared to irradiation with the rotary method. Moreover the dimension of most therapeutic rooms is usually too small to realize the total skin electron irradiation methods with SSD distance higher than 350 cm. Patient set-up and rotation during irradiation (based on rotary method) allow to reduce the number of dual fields used in Stanford method from six fields to one dual field (rotary-dual method). This modification leads to reduction of time assigned for set-up verification). Presented results of in-vivo dosimetry for selected patients treated in Great Poland Cancer Centre confirm the needfulness for using additional local for areas of perineum, scalp vertex, hands, neck-shoulders, plants.Moreover, obtained results indicate that total dose prescribed for additional fields depends on height and obesity and should be prescribed individually for each patient