研究用反應器生產治療用同位素扮演十分重要的角色，同時這些治療用同位素可廣泛應用於轉移性骨痛舒緩治療，腫瘤治療，滑膜液放射切除術及心臟血管狹窄放射治療等。鈥-166、鎦-177及錸-185等貝他同位素可以利用低中子通量反應器(1013-1014 n/cm2/sec)經由(n,r)核反應獲得，另外鎢-188、錫-117m及銅-67等同位素則需藉由高中子通量(大於5×1014 n/cm2/sec)核反應獲得，其中鎢-188同位素之生產必須以鎢-186照射靶經二次中子核反應，然後以鎢-188鹼性溶液研製發生器，再滋生錸-188子核種(半衰期16.9小時最高貝他2.12 MeV)，此方式所生產之錸-188放射液因生度過程簡易，價格便宜，比放射活度高，發生器可長久使用，甚具經濟價值。錫-117m(半衰期15天，放射內轉換電子)，可經由(n,n',r)核反絕產生，再製備成錫(Ⅳ)-DTPA標幟物後，應用於骨痛治療，於骨髓之吸收量小，副作用低。另外鈧-47(半衰期3.42天)則可以鈦-47為射靶，經(n,p)核反應生產，鈦-47與單株抗體結合後應用腫瘤治療。美國橡樹嶺國家實驗室高中子通率同位素反應器是一多功能研究用反應器，其最重要任務之一即是生產醫用同位素，包括鉲-252、鏑-166、鎦-166、錸-186、錫117m、鎢-188等。HFIR爐心照射設施包括有專為同位素生產之水送管照射設施乙支(可放置9只照射靶)，其特點是可於反應器運轉期(HFIR運轉週期為22~24天)放置或取出照射靶。
最近HFIR因應同位素擴量生產需求，於爐心周邊設計6套垂直照射設施(每套可放置8只照射靶)，因此總計可提供57個照射靶位置，是目前可照射量的6倍，惟爐邊照射設施需要於停爐期間放置或取出照射物。本篇報告將討論HFIR生產核醫治療用同位素現況及其應用與展望。

Research reactors continue to play an important role for the production of "neutron-rich" therapeutic radioisotopes which have important applications in nuclear medicine, oncology and interventional cardiology Important applications include the palliative treatment of metastatic bone pain, tumor therapy, treatment of arthritis and the inhibition of coronary restenosis following balloon angioplasty. A variety of β-emitting therapeutic radioisotopes of current interest, such as holmium-166,lutetium-177 and rhenium-186, can be readily produced with low or moderate neutron flux reactors (i.e. thermal neutron flux 1013~1014 neutrons/cm2/sec) via the simple radiative neutron capture route (n,γ). A high thermal neutron flux of >5 × 1014~ > 1 × 1015 neutrons/cm2/sec or a significant epithermal component is required, how-ever, for effective production of several important radioisotopes such as tin-117m, tungsten-188 and cop-per-67. Tungsten-188 is produced by double neutron capture of tungsten-186 and used in a generator sys-tem as the parent of rhenium-188 (16.9 h, 2.12 MeV),which is of wide interest as an inexpensive therapeutic radioisotope available on demand from the generator with a long useful shelf-life of several months. Tin-117m (15 days, conversion electrons) is used for preparation of tin (IV)-DTPA for bone pain palliation and is most effectively produced by the inelastic tin-117 (n, n', γ) tin-117m route, while scandium-47 (3.42-day half-life, β-emitter) for preparation of radiolabeled antibodies for tumor therapy is a key example which can be produced by the titanium-47 (n, p) scandium-47 route. A high neutron flux is also an important advantage when target volume is limited, and allows production of higher specific activity products and conserves expensive enriched target isotopes. The ORNL High Flux Isotope Reactor (HFIR) has a very high thermal neutron flux of about 2.5 × 1015 neutrons/cm2/sec (85 MW) and represents a unique resource for the production of a wide variety of medical radioisotopes. The versatile target irradiation and handling facilities provide the opportunity for production of a wide variety of therapeutic radioisotopes of current interest. Key examples include californi-um-252, dysprosium-166, holmium-166, lutetium-177, rhenium-186, tin-117m and tungsten-t88. The nine hydraulic tube (HT) positions in the central high flux region permit the insertion and removal of targets at any time during the 22-24 day operating cycle. To increase the irradiation capabilities of the HFIR, special target holders have recently been installed in the six Peripheral Target Positions (PTP), which are also located in the high flux region. These positions are only accessible during reactor refueling and are used for full cycle irradiations, such as required for the production of tin-117m and tungsten-188. Each of the six PTP tubes houses a maximum of eight HT target holders, which has increased the maximum number of HT targets from 9 to 57, significantly expanding the high flux target vol-