Brachytherapy

The two commonly used methods for radiation therapy are external-beam radiotherapy and brachytherapy.26 In external-beam radiotherapy, doses of 70 to 75 Gy are delivered in 35 to 41 fractions in patient with low-grade prostate cancer and 75 to 80 Gy for those with intermediate- or high-grade prostate cancer. Brachytherapy involves the permanent implantation of radioactive beads of 145 Gy of 125I or 124 Gy of 103Pd and generally is reserved for individuals with low-risk cancers. 

Brachytherapy A procedure in which radioactive material, sealed in needles, seeds, wires, or catheters, is placed directly into or near a tumor. Also called internal radiation, implant radiation, or interstitial radiation therapy. 

Protection Against Radiation From Brachytherapy Sources... 

Motility marker constructed of radiopaque plastic (a CDRH regulated device) Brachytherapy capsules, needles, and so on, that are radioactive and may be removed from the body after radiation therapy has been administered (a CDRH regulated device)... 

Radiation therapy The use of high-energy radiation from x-rays, gamma rays, neutrons, and other sources to kill cancer cells and shrink tumors. Radiation may come from a machine outside the body (external-beam radiation therapy), or it may come from radioactive material placed in the body in the area near cancer cells (internal radiation therapy, implant radiation, or brachytherapy). Systemic radiation therapy uses a radioactive substance, such as a radiolabeled monodonal antibody, that circulates throughout the body. Also called radiotherapy, [nih]... 

Radiotherapy is a local treatment aiming to achieve local control or cure of locally confined tumours. It cannot treat metastases. Radiotherapy may be administered as external beam radiotherapy with X-rays or gamma rays, in sealed radioactive sources (e.g. prostate brachytherapy), or unsealed sources (e.g. orally administered radioiodine for thyroid cancer, intravenous strontium-89 for bone metastases). In external beam radiotherapy, the X-ray or gamma ray beams are targeted at the tumour to damage and kill the tumour cells. Inevitably, surrounding normal tissues are also affected resulting in the early and late side effects of radiotherapy. 

Brachytherapy An increased risk of thrombus formation has been associated with the use of bivalirudin in gamma brachytherapy, including fatal outcomes. 

Sneed PK, McDermott MW, Gutin PH. Interstitial brachytherapy procedures for brain tumors. Semin Surg Oncol 1997 13 157-166. 

No distinct advantage has been noted when other forms of external beam irradiation, other than photons, or brachytherapy have been used. Neutron irradiation has not proven to be better than photons for stage III inoperable NSCLC (14,15). The use of brachytherapy has been limited to endobronchial treatment for palliation or as a boost after external beam. There have been institutional reports of interstitial brachytherapy, also usually done as aboost. Neither of these two approaches has been shown to be superiorto external beam (16,17). 

Brach B, Buhler C, Hayman MH, et al. Percutaneous computed tomography-guided fine needle brachytherapy of pulmonary malignancies. Chest 1994 106 268-274. 

Aygun C, Weiner S, Scariato A, et al. Treatment of non-small cell lung cancer with external beam radiotherapy and high dose rate brachytherapy. Int J Radiat Oncol Biol Phys 1992 23 127-132. 

Gaspar LE, Winter K, Kocha WI, Coia LR, Herskovic A, Graham M. A phase I/II study of external beam radiation, brachytherapy, and concurrent chemotherapy for patients with localized carcinoma of the esophagus (Radiation Therapy Oncology Group Study 9207) final report. Cancer 2000 88(5) 988-995. 

Nag S, Blatnik A, Soloway M. Enhancement of high intensity iodine-125 brachytherapy by cis-platinum in a murine bladder tumor model. J Urol 1984 131 1225-1228. 

In a typical low-dose rate (LDR) treatment in brachytherapy, the total irradiation time is on the order of several days and therefore = 0. It follows that the probability of cell survival S D), is quasi-exponential and the RBE is determined by the linear (a) coefficient, or, in microdosimetric terms, by zp-... 

The lineal energy spectrum of the brachytherapy source is evaluated from ... 

Brachytherapy physics is concerned with electrons, whether primary or secondary, as in the case of photon sources (Table 1). 

Table 1 Physical Characteristics of Radioactive Sources Currently Used in Brachytherapy...

Figure 3 Microdosimetric distributions for several photon radiations commonly used in brachytherapy. (From Ref. 36.)...

The specific techniques of brachytherapy and the administration of unsealed sources of radionuclides, in nuclear medicine [10], are not dealt with in this chapter. 

In brachytherapy, with the modern equipment now available, the clinically applied dose rates vary within large limits. The ICRU and the international brachytherapy community are recommending weighting factor, IIhdr and IIpdr, to compensate for the differences in dose rate for high dose-rate (HDR) and pulse dose-rate (PDR) brachytherapy, respectively. 

Staff preparing radiopharmaceuticals to be administered for nuclear medicine diagnostic and therapeutic procedures and handling sealed sources for brachytherapy use protective blocks to shield the head and trunk. For these workers, a single personal monitor is located on the trunk. ... 

Order, S.E., Siegel, J.A., Principato, R., Zeiger, L.E., Johnson, E., Lang, P. et al. (1996) Selective tumor irradiation by infusional brachytherapy in nonresectable pancreatic cancer a phase I study. Int. J. Radiat. Oncol. Biol. Phys., 36, 1117-1126. 

Protection Against Radiation from Brachytherapy Sources (1972)... 

However, we have no data to support the concept of prolonged (>l year) dual antiplatelet treatment except in patients who underwent vascular brachytherapy for in-stent re-stenosis. Due to the lack of re-endothelialization, this small group of patients should receive the dual treatment for life (49,50). 

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