TIMED-BIORESORBABLE RADIOSEEDS FOR PROSTATE CANCER

用于前列腺癌治疗的放射性同位素主要是光子/γ-发射体（I-125、Pd-103、Ir-192）。暂时性和永久性伽马放射性粒子都已被接受用于前列腺间质植入。然而，由于更大的组织穿透性，伽马辐射可在患者中引起副作用，例如胃肠道不适，可对前列腺外的健康组织造成损害，并且可对医院工作人员和家庭成员造成危险。该I期研究的目的是证明使用定时生物可吸收玻璃基质封装高能β发射放射性同位素（如Y-90）的可行性。理想情况下，来自这种玻璃的种子在10个半衰期内不会泄漏放射性，并且将以预定的速率被完全生物吸收。定时生物可吸收放射性粒子具有以下优点：（a）简单的门诊植入程序;（B）在向肿瘤递送高剂量的同时保留健康组织;以及（c）最小或没有健康危害或副作用，因为所有的β能量都沉积在组织中的8-9 mm内。此外，化学预防剂可以掺入定时生物可吸收基质中，使得它们随时间的释放将有助于预防癌症的复发。如果成功，定时生物可吸收玻璃放射性种子将成为永久性种子的低成本替代品，并将对前列腺和其他癌症的放射治疗产生积极影响。拟议的商业应用：生物可吸收放射性粒子在治疗实体瘤和实现各种其他局部放射治疗方面具有很大的前景。此外，生物可吸收的种子将能够将化学预防剂递送到肿瘤部位，因为正在进行的临床试验显示这种药物是有价值的。

Radioisotopes used for prostate cancer treatment are predominately photon/gamma-emitters (I-125, Pd-103, Ir-192). Both temporary and permanent gamma-emitting radioseeds have gained acceptance for interstitial implantation in the prostate. Due to greater tissue penetration, however, gamma radiation can cause side effects in the patient such as gastrointestinal discomfort, can cause damage to healthy tissues outside the prostate, and can be hazardous to hospital personnel and family members. The objective of this Phase I research is to demonstrate the feasibility of using timed-bioresorbable glass matrices to encapsulate high energy, beta-emitting radioisotopes such as Y-90. Ideally, seeds from such glasses will not leak radioactivity within 10 half-lives, and will be completely bioresorbed at a predetermined rate. Timed-bioresorbable radioseeds have the advantages of (a) simple outpatient implantation procedures; (b)sparing healthy tissue while delivering a high dose to the tumor; and (c) minimal or no health hazards or side effects, since all of the beta energy is deposited within 8-9 mm in tissue. In addition, chemoprevention agents can be incorporated into the timed-bioresorbable matrix so that their release over time will help to prevent the reoccurrence of the cancer. If successful, timed-bioresorbable glass radioseeds will be a low cost alternative to permanent seeds, and will positively impact radiation therapy of prostate and other cancers. PROPOSED COMMERCIAL APPLICATIONS: Bioresorbable radioseeds hold a great deal of promise for the treatment of solid tumors and for effecting a variety of other localized radiation therapies. In addition, the bioresorbable seeds would be capable of delivering chemoprevention agents to the site of the tumor as on-going clinical trials show such agents to be of value.