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Local control (%)965-year (%)7-year (%)100*92.0*93.2*76.7*100*95.1*96.1*83.6*98.7**98.3**100***84***78***40***10-year (%)100*89.2*85.7*95.9**95.3**the target itself without any harmful effects10), and may be a future direction of research and thera‑peutics.In 2000, Ling et al. proposed a concept known as “biological target volume”11). As mentioned above, multiple modalities can be used to precisely irra‑diate the target volume. However, defining the target volume, which is usually based on anatom‑ical images, remains a problem. Ling et al. proposed the use of biological and mechanistic data to delin‑eate target volumes. Biological images broadly include metabolic, biochemical, physiological, func‑tional, molecular, genotypic, and phenotypic. Although positron emission tomography (PET) using 18F- fluorodeoxyglucose (FDG) is available for this purpose at Juntendo (Figure 1), other imaging modalities, such as 18F-misonidazole PET for hypoxic cells, have been tested at other institu‑tions12, 13). With advances in diagnostic and imaging modalities, functional imaging is anticipated to be introduced in this field in the future. Lack of qualified personnel in this field is a major issue in Japan. There were only 899 certified radia‑tion oncologists (ROs), 1213.9 full-time equivalent (FTE) ROs, and 295.7 FTE medical physicists, despite 846 institutions treating patients using radiotherapy in 20151). Juntendo also contends with this problem, and will be addressed later.Radiation therapy as a standard treatment for cancerAs shown in Table 1, radiation therapy can achieve 336DiseaseProstatic cancerBreast cancerUterine cervical cancer ***SRT for lung cancer*Biochemical relapse free rate, **the ipsilateral breast tumor control rate, Yoshida‑Ichikawa Y et al. Breast Cancer 2021 Jan; 28(1): 92‑98***Overall survival, SRT: stereotactic radiation therapyTable 1　Radiation therapy results for representative diseases at Juntendo University HospitalLow riskIntermediate riskHigh riskSalvage radiation therapyConventional fractionationAccelerated fractionationStage IStage IIStage IIIStage IVAgood treatment results. Although it sometimes causes undesirable adverse events, it is generally less invasive than other modalities, and can preserve the shapes and functions of healthy organs. Therefore, it is regarded to be standard treatment for many types of malignant diseases and appears in domestic and international treat‑ment guidelines for cancers. The therapy can be used not only as monotherapy, but can also be combined with other methods, including surgery, chemotherapy, and/or immunotherapy.Radiation therapy at Juntendo UniversityWhen I was appointed to Juntendo University in 2000, the Radiation Oncology Division was a small part of the Department of Radiology. There was only one other RO with the exception of myself, although the individual was young and uncertified. Juntendo University had only two old-type Linacs (one at Juntendo University Hospital and another at Urayasu Hospital, Chiba, Japan). The term “radiology” does not necessarily refer to radiation oncology (therapy) but refers to diag‑nostic radiology in the United States and major European countries. Because cancer is a leading cause of death, the Japanese government created the “Basic Plan to Promote Cancer Control Programs” based on the Cancer Control Act. One of the major policies is to promote radiation therapy, with the government encouraging each medical school to establish a radiation oncology department. In 2013, Juntendo University also established the