Total Body Irradiation (TBI) is a form of radiotherapy used for patients prior to bone marrow or stem cell transplant to destroy any undetectable cancer cells. The dosimetry characteristics of a 60Co unit for TBI were studied and a simple method for the calculation of the prescribed dose for TBI is presented. Dose homogeneity was verified in a human phantom. Dose measurements were made in water phantom (30 × 30 × 30 cm3), using farmer ionization chamber (0.6 cc, TM30010, PTW) and a parallel plate ionization chamber (TM23343, PTW). Point dose measurements for AP/PA irradiation were measured in a human phantom using silicon diodes (T60010L, PTW). The lung dose was measured with an ionization chamber (0.3 cc, TM31013). The validity of the proposed algorithm was checked at TBI distance using the human phantom. The accuracy of the proposed algorithm was within 3.5%. The dose delivered to the mid-lobe of the lung was 14.14 Gy and it has been reduced to 8.16 Gy by applying the proper shield. Dose homogeneity was within ±7% for all measured points. The results indicate that a good agreement between the total prescribed and calculated midplane doses can be achieved using this method. Therefore, it could be possible to use calculated data for TBI treatments.

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Background: There are miscellaneous methods of boost field determination with different levels of accuracy. One of the important parameters in boost field planning is the tumor bed depth, as it is important for determining electron energy. Objectives: The purpose of present research was the determination of ultrasound accuracy to estimate the appropriate depth for the tumor bed. Patients and Methods: Patients who were undergone breast conservative surgery with placing of 5 clips in the tumor bed (lower, upper, medial, lateral, and posterior) were included. The depth and location of the tumor bed were determined using ultrasonography. The optimum field boost was planned with an appropriate 2.5 cm margin. After putting the marker on the field boost, the CT simulation was done and then the obtained depth of the ultrasound report and that of the CT scan-clips were compared. Results: Twenty five patients were included. The average depth reported by the ultrasound was about 18 mm ± 3 mm (range 10-26 mm), and the average obtained from the CT scan-clips was about 48 mm ± 13 mm (range 24-80 mm), (P Value = 0.001). In almost all cases, the depth obtained from the ultrasound was less than that obtained from the CT scan-clips. Conclusions: Ultrasound is not an accurate method to determine the appropriate depth and field for determination of breast field boost. Thus, it is better not to use ultrasound to estimate the tumor cavity depth; the CT scan images with surgical clips should be used instead.

In the present study, a case was reported concerning a patient with a bulky extremity soft tissue sarcoma treated with spatially fractionated Grid therapy and then followed by standard external beam radiotherapy. Treatment was performed using a Grid block to deliver 15 Gy in one fraction. There was one week interval break before EBRT treatment with 50 Gy in 25 fractions for the neoadjuvant external beam radiotherapy. The surgery was performed 4 weeks after the completion of radiotherapy. The follow-up time was considered as 24 months. The patient's general condition was good during this period without the presence of tumor recurrence or grade 3 or 4 treatment-related toxicities. Combining different treatment techniques like grid therapy is feasible and may improve the outcomes in the management of bulky high-grade soft-tissue sarcomas of the extremities.