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/伽马发射体(I-125、Pd-103、Ir-192)。无论是暂时性的还是永久性的伽马放射粒子，都已被接受用于前列腺组织间植入。然而，由于更大的组织渗透率，伽马辐射可能会导致患者的副作用，如胃肠道不适，可能会对前列腺以外的健康组织造成损害，并可能对医院工作人员和家庭成员造成危险。这项第一阶段研究的目的是证明使用定时生物可吸收玻璃基质来封装高能、贝塔发射的放射性同位素(如Y-90)的可行性。理想情况下，这种玻璃的种子不会在10个半衰期内泄漏放射性，并将以预定的速度完全被生物吸收。定时生物可吸收放射种子具有以下优点：(A)简单的门诊植入程序；(B)节省健康组织，同时向肿瘤提供高剂量；以及(C)最小或没有健康危害或副作用，因为所有的β能量都储存在组织中8-9毫米内。此外，可以将化学预防药物加入到定时生物可吸收基质中，以便随着时间的推移，它们的释放将有助于防止癌症复发。如果成功，定时生物可吸收玻璃放射种子将成为永久种子的低成本替代品，并将对前列腺癌和其他癌症的放射治疗产生积极影响。拟议的商业应用：可生物吸收的放射种子在实体肿瘤的治疗和其他各种局部放射治疗方面有很大的前景。此外，生物可吸收种子将能够将化学预防药物输送到肿瘤部位，因为正在进行的临床试验表明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.