Estimations suggest that about 60% of all cancer patients will require some form of radiation therapy during their lifetime. Although 40 to 50% of cancer patients in Europe and the United States recieve radiation therapy, only about 20% of patients with cancer in Japan undergo such treatment. This is largely due to the lack of understanding of the role of radiation therapy by many medical personnel in Japan, as well as to “radiation allergy” among many of the general population in Japan, a country that has been undergone atomic bombing. From our perspective as specialists in radiation therapy, the chronic shortage of radiation oncologist also poses a serious problem. Although there are approximately 700 hospitals throughout Japan where radiation therapy is available, no more than half this number of medical facilities have a full-time radiation oncologist. Perhaps the reason for this is that radiation therapy is perceived as unnecessary in Japan. However, it is absolutely essential. In our experience, the 5-year relative survival rate of patients with malignant tumors who have undergone radiation therapy in our clinic is 65 percent. Thus, radiation therapy has proven very useful in the treatment of malignant tumors. Moreover, better estimates of prognosis of cancer patients treated with radiation therapy are becoming possible. This article discusses the role of radiation therapy, from a radiation pathological perspective, in a multidisciplinary approach to treatment of cancer patients. I also emphasize the critical importance of training radiation oncologists who can function as part of multidisciplinary teams that care for patients with malignant tumors.

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There are cases in which, although all traces of acute radiation complications seem to have disappeared, late complications may appear months or years to become apparent. Trauma, infection or chemotherapy may sometimes recall radiation damage and irreversible change.
There were two cases of breast cancer that received an estimated skin dose in the 6000 cGy range followed by extirpation of the residual tumor. The one (12 y.o.) developed atrophy of the breast and severe teleangiectasis 18 years later radiotherapy. The other one (42 y.o.) developed severe skin necrosis twenty years later radiotherapy after administration of chemotherapy and received skin graft.
A case (52 y.o.) of adenoidcystic carcinoma of the trachea received radiation therapy. The field included the thoracic spinal cord which received 6800 cGy. Two years and 8 months after radiation therapy she developed complete paraplegia and died 5 years later.
A truly successful therapeutic outcome requires that the patient be alive, cured and free of significant treatment-related morbidity. As such, it is important to assess quality of life in long-term survivors of cancer treatment.

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Purpose: The object of this study is to evaluate the clinical feasibility of segmented abutting fields irradiation (SAFI) using multileaf collimators (MLCs), in which the target volume is divided into several segments to create complex irregular field without use of alloy blocks.
Materials and Methods: A linear accelerator with 26 pairs of roundly ended MLCs of 1cm in width was tested in this study. In SAFI, radiation leakage occurs at the abutment sites with these MLCs. Film dosimetry was used to determine the optimal length of the MLC overlap to minimize dose profile variation in abutting fields. A mantle field was investigated as a clinical application.
Results: 1. Without overlapping the MLCs, radiation leakage at the abutments appeared as a peak of the dose profile. With more overlapping, the profile exhibited a minimized variation with a two-peak pattern. With excessive overlapping, the peak was reversed due to decreased dose.
2. Variation of the profile was minimized with an overlap of 2.0-2.2mm. The level of variation and the optimal length of overlap were found to be independent of the sites of measurement. Reproducibility was confirmed by repeated measurements.
3. With the mantle field, SAFI using MLCs revealed an profile equivalent to use of alloy blocking fields in all respects other than the variations at the abutting sites.
Conclusion: If the length of the MLC abutment overlap differs by site, clinical application of SAFI using MLCs would be quite complicated. The optimal length of the overlap was found to be 2.0mm and to be independent of the sites of abutment. Therefore, we conclude that SAFI using MLCs of 1cm in width is feasible for clinical use.

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The relative biological effect (RBE) of carbon ion beams on mouse intestinal crypt cells were studied. Survival fractions of apoptotic sensitive cells, mitotic delay and colony assay were used for endpoints. Female C3H mice were total body irradiated using a carbon ion beam (290 MeV/u, 6cm SOBP) at the National Institute of Radiological Science. For counting apoptosis and mitosis, the animals were irradiated either at LET of 70keV/mm or 40keV/mm. Fifteen minutes after irradiation, the mice received vincristine sulfate (0.8mg/kg) and were sacrificed 2 hours and 45 minutes later. For colony assay, the animals were irradiated at an LET of 70 keV/mm and were sacrificed 3.5 days later. Jejunum were excised, fixed and cut into slices. The slides were stained with Hematoxylin and Eosin. Apoptosis-pyknotic cell-and mitosis were counted and survival fractions of apoptotic sensitive cells and mitotic delay time were obtained. The number of colonies were counted and survival fractions per circumference were obtained. Using these endpoints, RBEs were obtained. For survival fractions of apoptotic sensitive cells, no LET difference was observed and RBE was 1.7. For mitotic delay time, RBE was 2.3 and 1.7 at an LET of 70 keV/mm and 40 keV/mm, respectively. For colony assay, the RBE was 2.0-2.1. The different RBEs from three endpoints of the jejunal crypt may reflect each nature of the radiosensitivity to the carbonion beam. In summary that mitotic delay time exhibited the same RBE as colony assay and RBE regarding apoptosis was less than those RBEs.

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It's well-known that a radiotherapy should be done, Based on the correct patient setup at the planning and on the accurate sighting a radiation shooting beam to tumor targets in human body.
In general, the irradiation field will be determined by the X-ray simulator referring clinical images, e.g. radiograph, CT's, MRI's, etc.
Nowadays, EPID (which stands for Electronic Portal Imaging Device) has been installed in the oncology institutions, by that the fluoroscopic monitoring images would be displayed to check the patient setup mobilization during radiotherapy.
However, there's still room for doubt in the correct localization, i.e., therapists and oncologists judge the irradiation field size, that was localized by the materials of EPID and graph of LINAC, with the subjective naked eyes.
So we tried to collate localization image with images of DSA, MRI and CT as reference, and collate portal image with localization film with machinery. When we collate, problems of image distortion and geometric magnification on each modalities have occurred.
To solve these problems, we composed correction table for image distortion, and led automatic verification for a quantitative analysis of irradiation field. For this system, we could provide high precision of radiation therapy.

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In treatment planning of photon radiation therapy, obtaining accurate attenuation of inphantom primary water collision kerma is important for accurate evaluation of the in-phantom primary and scatter absorbed dose. In-air chamber readings are often taken for evaluation of the attenuation of in-phantom primary water collision kerma. Using the Await concept, theoretical consideration is given to the evaluation method and the following conclusions are drawn:(i) For beams with multiple photon energies, the evaluation method can be perfectly valid only under certain extreme conditions. However, if the build-up cap is made of a low Z material like acrylic or aluminum and if its thickness is approximately equal to what is required for maximum dose build-up, the evaluation method can be valid with a high degree of accuracy.(ii) For beams with a single photon energy, the evaluation method can be perfectly valid without any particular conditions.

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Obtaining accurate attenuation of in-phantom primary water collision kerma is important for accurate evaluation of the in-phantom primary and scatter absorbed dose. Using a 10 MV x-ray beam generated by a linear accelerator with a lead flattening filter, we have developed a 10 MV x-ray attenuation coefficient expression for water as a function of depth (z) and off-axis distance (r), described herein. This paper also describes a 10 MV x-ray mean attenuation coefficient expression for water as a function of off-axis distance (r). From these, the following results have been obtained:(i) On any given fanline, the attenuation coefficient decreases exponentially with increasing z.(ii) At any given depth, the attenuation coefficient increases linearly with increasing r.(iii) The mean attenuation coefficient increases linearly with increasing r.(iv) For any given fanline, the mean attenuation coefficient derived from a set of transmission data for z=z₀ to z₀ is nearly equal to the attenuation coefficient for z=z₀.

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Treatment outcomes were analyzed retrospectively for 135 patients with brain metastases, who were treated with stereotactic radiosurgery (RS) or whole brain radiotherapy (WBRT) at Osaka City General Hospital between January 1994 and September 1996. The major primary site was the lung (74.8%). RS only was administered to 52 patients, WBRT only to 49 patients, and both RS and WBRT to 34 patients. Of the last group, 15 patients received a combination of WBRT and RS within a month of one another (sequential treatment), 19 patients (previously WBRT was administered to 12 patients, RS to 7 patients) were treated with RS or WBRT at the time of metastatic brain tumor recurrence (recurrence treatment).
RS was performed with the Leksell Gamma knife (maximum dose range: 17.5-57.5Gy, median 40Gy: peripheral dose range was 12.0-28.0 Gy, median 21 Gy). The dose range for WBRT was 30-50 Gy (generally, 1.5Gy b.i.d. for a total dose of 39Gy, which was used for WBRT only, and 1.5 Gy b.i.d. for a total dose of 30 Gy for sequential and recurrence treatment).
The median survival time for patients receiving RS only was 9 months, for WBRT only 7 months, for sequential treatment was 12 months and for recurrence treatment 19 months. There was no significant difference in survival rate between treatment RS only and WBRT only, but there was a significant difference (p<0.01) between sequential treatment and treatment with WBRT only. The death of 10 of the 61 patients was attributed to CNS progression (16% of all deaths). Improvement of neurologic signs and symptoms was seen in 34 of the 62 patients (54.8%). In the recurrence group, intracranial recurrence outside of the RS volume was seen in three of the six patients who were treated with RS only as the initial treatment.
It is concluded that WBRT in conjunction with RS for brain metastases as the initial treatment may be more effective for prolonging survival, especially for cases with no active extracranial disease.

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To evaluate the role of combined hyperthermia and radiotherapy in the management of soft tissue sarcoma, a multi-institutional retrospective analysis was under taken by the JASTRO Hyperthermia Study Group. Clinical records of soft tissue sarcoma treated with thermoradiotherapy in three Japanese institutions were reviewed. In total 71 tumors were enrolled at this study. Thirty-eight male and 33 female. Main treatment sites were lower limbs (26) and pelvic cavities (15). Maximum tumor diameter was 11.6±6.6cm and maximum tumor depth was 7.2±4cm. Average radiation dose was 47.1±14.1 Gy and average heating sessions and average heating time were 7.1±3 and 47.8±7.5min, respectively. Primary effect 1 month after combined treatment was CR in 8 tumors, PR in 25 tumors and NR in 38 tumors, and the overall response rate was 36%(33/71). Local response rate according to radiation dose, 33% at less than 30 Gy and 88% at more than 60 Gy, respectively. Higher radiation dose showed higher response rate. Correlation between intra-tumor (maximum, average and minimum) temperature and local response was analyzed. No positive correlation was observed. The relation between various factors including tumor and treatment parameters and survivals were analysed. Multi-variate analysis showed that the treatment site (lower extremities), tumor volume less than 800cm³, average heating time more than 45 min and no previous radiation history were statistically significant factors.

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[Purpose] A questionnaire survey was carried out to demonstrate the actual situation with respect to informed consent, especially written consent, at the radiation therapy department.
[Methods and Materials] On March 25, 1996, we sent the questionnaire to 119 institutes in the Kanto area that had a radiation therapy department. There were 56 eligible replies in the 61 institutes that replied by April 30 1996.
[Results] In 63% of the institutes, less than 50% of the patients who received radiotherapy were told the truth about their diseases; in 23% of the institutes, 50% to 75% of the patients were told the truth; in 14% of the institutes, more than 75% of the patients were told the truth. Patients with breast cancer or gynecological cancer were often told the truth. The policy of 66% of radiation therapy departments was submissive to the referring physician about telling truth.
Almost all radiation oncologists explained to the patients. Most explanations were devoted solely to the patients. Almost all explanations were done verbally. A few institutes used brochures for explanations, and a few institutes used written consents. The status of disease was explained concisely in many institutes, and the aim and methods of radiotherapy were explained in detail in many institutes. The primary response and radiation side effects to normal organs were explained concisely in many institutes, but no explanation was given in some institutes. Other treatment modalities and prognosis were not explained in many institutes.
[Conclusion] Problems exist in radiation therapy departments, such as almost all treatments are commissions from a referring physician, some cases are not told the truth of their condition, only part-time doctors treat the patients in some hospitals. But it is necessary for radiation oncologists to accommodate positively to the problems of the informed consent.

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