INTRODUCTION: Recently, young patients with breast cancer are increasingly more able to become pregnant in the future in Japan. The purpose of this study was to analyze the exposure dose of intrapelvic organs in patients with breast cancer who received radiotherapy to the breast region after breast-conserving therapy.
MATERIALS and METHODS: From July 2003 to June 2004, 14 patients with breast cancer- all had breast-conserving surgery and whole breast radiotherapy following surgery. The radiation dose to the whole breast was 50 Gy in 5 weeks with 2 Gy daily fractions, using 4 MV X-ray 10 Gy and a boost dose was administered to the tumor bed, using a 6 MeV electron beam. At the same time, the radiation dose at the patient's surface was measured using glass rod detectors (GRDs). In much the same way, the surface dose and intra pelvic dose of a rand-phantom were measured.
RESULTS: Average intrapelvic dose of the rand-phantom was 2.07 mGy for 2 Gy radiation for the breast of the rand-phantom. The average surface dose in the pelvic region of the rand-phantom was 9.47 mGy for 2 Gy radiation for the breast of the rand-phantom. Therefore, intrapelvic dose is 0.218 times as much as the surface dose in the pelvic region. Estimated intra pelvic dose is 1.2 mGy, according to this conversion factor for 2 Gy radiation for the breast. For radiotherapy of 50 Gy for the breast, the intrapelvic dose is estimated to be about 30 mGy.
CONCLUSION: Radiotherapy after breast-conserving surgery should not be avoided unreasonably to treat a patient who is able to become pregnant.

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The Japanese Association for Therapeutic Radiation Oncology (JASTRO) has had a seminar for medical students since 1995. Some of participants become radiation oncologists, so the seminar is considered to be effective for increasing the number of radiation oncologists in Japan. To reveal the participants' knowledge, clinical experience and familiarity with radiation oncology, we performed a small examination and questionnaire survey. We found that the satisfaction with the lectures during the seminar depended on the students' previous experience and knowledge. The daily efforts of the teaching staff in medical schools seems to be necessary to motivate students in radiation oncology.

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To increase the number of radiation oncologists, the Japanese Society for Therapeutic Radiology and Oncology (JASTRO) has provided a radiation oncology seminar for medical students and interns during the summer vacation since 1995. We examined the specialty of the 234 participants to reveal that seminar contributed to an increase of the number of radiation oncologists. Eighty five (36.3%) became radiologists and 41 (17.5%) chose radiation oncology as their specialty. The number of students who became radiation oncologists is significantly different in each of the seminars. There is the possibility that these seminar encourage students to choose radiation oncology as their specialty.

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We treated 65 patients, from October 2003 to October 2004, with I-125 prostate brachytherapy who had prostate confined adenocarcinoma. Thirty-one patients had pre-implant CT on the day before prostate implantation. We compared pre-implant prostate volume by TRUS and CT. Eighteen patients had hormonal therapy at least 3 months before the volume study by TRUS. Average prostate volume by TRUS and CT were 23.74 (9.0-39.63) cm³, and 24.23 (9.36-41.38) cm³. The average differences of prostate volume by the two modalities in each patient were 1.26 (0.05-3.49) cm³, and the median differences were 0.99 cm³. There was no definite difference between the two modalities. The median number of seeds that were planned by TRUS volume study and CT volume study were 64 (range 46-85), and 65 (range 45-86) respectively. The average differences of the number of seeds by the two modalities in each patient was 0.6 (range 0-4). We believe the volume study by CT can be used as substitute for an ordinary volume study by TRUS.

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