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Aim: Late adverse effects following radiation therapy for prostate cancer involve the urinary and lower gastrointestinal tracts, with continuous rectal bleeding being the most serious issue. We focused on late adverse effects, particularly rectal bleeding after volumetric-modulated arc therapy (VMAT), for patients with locally advanced prostate cancer. Materials and Methods: Seventy-three patients with localized prostate cancer were treated with radiation therapy using VMAT with an image-guided radiation therapy system. Patient age at the start of irradiation ranged from 54 to 81 years (median, 71 years). The follow-up period ranged from 23 to 87 months (median, 57 months). The prescribed total irradiation dose was 76 Gy in 38 fractions. Results: Late rectal bleeding was observed in 14 (19%) patients, with nine (12.3%), four (5.5%), and one (1.4%) being classified as grades 1, 2, and 3, respectively. One grade 3 patient with rectal bleeding had severe diabetes and was administered intravenous warfarin for cardiomyopathy. Findings: VMAT may provide better accuracy and involve fewer time constraints for patients compared with other intensity-modulated radiation therapy (IMRT) methods. The incidence of late rectal bleeding in VMAT is almost equivalent to that of other IMRT methods. [ABSTRACT FROM AUTHOR]

Abstract: The 3α-cluster structure of excited states in 12C is investigated by taking into account the correct boundary condition for three-body resonant states. In this study, we adopt the Complex Scaling Method (CSM), which enables us to obtain the resonant states that can be described as square integrable states with the same boundary conditions as those of the bound states, and calculate not only resonance energies but also the total decay widths of the 3α system. We compare the calculated resonance parameters to the experimental data and also to the previous 3α model results obtained with a bound state approximation. Our results well explain the many observed levels and give an assurance for the presence of the second state, which is expected by the 3α model calculations with the approximations of bound state or two-body scattering. As for the negative-parity states, it is considered that the calculated state is assigned to the observed state. Through the calculation of channel amplitudes, the obtained third state is found to have a s-wave dominant and a more dilute structure compared to the second state. [Copyright &y& Elsevier]

We investigate the three-body Coulomb breakup reaction of two-neutron halo nuclei [sup 11]Li, where we adopt the extended three-body model of [sup 11]Li with paying attention to the pairing correlation of the nuclei, and also employ the complex scaling method (CSM) to solve the three-body unbound states of [sup 11]Li. From the results, we cannot find any dipole resonances, at least, having small decay widths. This means that the breakup strength is exhausted by the continuum states. We compare the obtained strength showing the low energy enhancement to the several experimental data. [ABSTRACT FROM AUTHOR]

Objectives: To develop a method for detecting jaw positions during jaw-tracking delivery to ensure an accurate delivery of radiation to patients using an electronic portal imaging device (EPID) in the cine mode on a linear accelerator for radiotherapy., Materials: A bidirectional picket fence (BPF) plan was used in a novel application to detect jaw positions during jaw-tracking delivery. In the BPF plan, jaws tracked multileaf collimator (MLC) apertures. The irradiated patterns were acquired by an EPID in the cine mode., Methods: The upper- and lower-half leaves in the MLC moved in opposite directions to facilitate detection of jaw positions on EPID images. A picket-fence-like image was created by summing all acquired cine images and evaluated to detect MLC leaf positions., Results: Jaw positions determined on the cine images were compared with those expected from the delivered BPF plan. The absolute differences (average ± 1 standard deviation) were 0.16 ± 0.19 mm for the X1 jaw and 0.11 ± 0.16 mm for the X2 jaw. The maximum error in the MLC leaf positions detected in the picket-fence-like pattern were 0.11 mm., Conclusions: Jaw positions during jaw-tracking delivery were identified using the cine EPID images and could be determined within an accuracy better than 0.5 mm. The BPF plan is also available as a picket fence test and can determine the MLC leaf positions to an accuracy better than 0.5 mm., Competing Interests: The authors declare that there are no conflicts of interest., (© 2022 The Juntendo Medical Society.)

Objectives: In radiation therapy, the field-in-field (FIF) technique is used to prevent the administration of unnecessarily high doses to reduce toxicity. Recently, the FIF technique has been used for whole brain irradiation (WBI). Using the FIF technique, the volume that receives a higher than prescribed dose (hotspot) can be largely reduced; however, the treatment planning requires time. Therefore, to reduce the burden on the treatment planners, we propose a semiautomatic treatment planning method for the FIF technique., Methods: In the semiautomatic FIF technique, hotspot regions in a treatment plan without the FIF technique are identified three-dimensionally, and beams with blocks that cover the hotspot regions using a multileaf collimator (sub-beams) are automatically created. The sub-beams are added to the original plan, and weights are assigned based on the maximum dose of the original plan to decrease the doses in the hotspot regions. This method was applied to 22 patients previously treated with WBI, wherein treatment plans were originally created without the FIF technique., Results: In the semiautomatic FIF plans, the hotspots almost disappeared. The dose to 95% of the volume and the volume receiving at least 95% of the prescribed dose in the planning target volume decreased by only 0.3% ± 0.2% and 0.0% ± 0.1%, respectively, on average compared with those in the original plan. The average semiautomatic FIF processing time was 28 ± 4 s., Conclusions: The proposed method reduced the hotspot regions with a slight change in the target coverage., Competing Interests: There are no conflicts of interest in relation to this study., (© 2022 The Juntendo Medical Society.)

To realize the high precision radiotherapy, localized radiation field of the moving target is very important, and visualization of a temporal location of the target can help to improve the accuracy of the target localization. However, conditions of the breathing and the patient's own motion differ from the situation of the treatment planning. Therefore, positions of the tumor are affected by these changes. In this study, we implemented a method to reconstruct target motions obtained with the 4D CBCT using the sorted projection data according to the phase and displacement of the extracorporeal infrared monitor signal, and evaluated the proposed method with a moving phantom. In this method, motion cycles and positions of the marker were sorted to reconstruct the image, and evaluated the image quality affected by changes in the cycle, phase, and positions of the marker. As a result, we realized the visualization of the moving target using the sorted projection data according to the infrared monitor signal. This method was based on the projection binning, in which the signal of the infrared monitor was surrogate of the tumor motion. Thus, further major efforts are needed to ensure the accuracy of the infrared monitor signal.

Radiotherapy has been widely used in breast cancer in many situations. These are breast irradiation of breast conserving therapy,post mastectomy regional irradiation,irradiation for regional lymph nodes recurrence,breast irradiation of inoperable locally advanced cases,palliative irradiation of brain metastasis,bone metastasis and so on. The relationship among radiotherapy,surgery and systemic therapy has to be considered in those situations. In breast conserving therapy, the usefulness of breast irradiation is well established. Otherwise, a local controllability depend on a grade of residual tumor cell has not been understand. The authors conducted the survey of 941 cases of positive surgical margins and found that doses more than 60 Gy has a tendency for better local control in post menopausal cases. To reduce patient's burden,3 weeks short course irradiation (Canadian protocol) or accelerated partial breast irradiation have been introduced in breast irradiation. A subgroup which has no need to irradiate to conserving breast had not been identified. The timing between postoperative chemotherapy and irradiation is another point that has to be considered. To reduce distant metastasis,chemotherapy first has been considered better. As for post mastectomy regional irradiation, improvement of local and systemic control has been widely known these days. A timing of systemic therapy and irradiation is a point has to consider. In inoperable or far advanced T 4 tumors, breast irradiation with concurrent chemotherapy must be considered in stead of surgery. We have to know a big shortage in Japanese cancer treatment situation that we have few radiation oncologists or medical physicists in Japan. We have to educate those specialists to catch up with increasing cancer patients.