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At least 145 records · Page 8Linked to original sources
PubMed1995

Pineal region tumours treated with interstitial brachytherapy with low activity sources (192-iridium).

Three patients with tumours of the pineal region underwent interstitial Ir-192 brachytherapy. Histological diagnoses were obtained in all patients, by stereotactic biopsy and included one germinoma, one mixed pineoblastoma/pineocytoma, and one astrocytoma grade III. Our approach to pineal region neoplasms is first to decide whether stereotactic biopsy or surgery should be performed. When a pineal lesion is thought to be benign on the basis of imaging, such as benign teratoma, surgery is performed to resect the entire lesion. When a definitive diagnosis is not possible, stereotactic biopsy is performed to obtain a histological diagnosis for treatment planning, using a Brown-Roberts-Wells (BRW) stereotactic apparatus with computed tomography (CT) or magnetic resonance imaging (MRI). When a lesion is malignant and localized, stereotactic implantation of catheters for interstitial brachytherapy is performed simultaneously. Radioactive Ir-192 seeds are inserted into the catheters and maintained for 5-10 days to give 36 Gy of irradiation at the tumour periphery. Sequential CT scans and MRI after treatment revealed tumour disappearance in two patients with germinoma and high grade astrocytoma and tumour reduction in the patient with mixed pineoblastoma/pineocytoma. No significant morbidity or mortality occurred in any of these patients after stereotactic biopsy and brachytherapy. The technique and the advantages of this therapeutic approach to selected pineal region tumours are described and discussed.

Adult↗
PubMed1985

Planning of Ir-192 seed implants for boost irradiation to the breast.

The conservative management of early stage breast cancer with tumor excision and irradiation of the breast is becoming increasingly accepted as an alternative to modified radical mastectomy. The radiotherapy typically consists of 45 to 50 Gy delivered with external beam irradiation, followed by boost irradiation of 15 to 20 Gy to the tumor bed using electron beams or interstitial implantation. Pathological evaluation of the excised tumor, clinical assessment, and mammography are used to determine the tissue volume potentially containing a residual tumor burden and therefore requiring boost irradiation. In this paper we describe planning and implantation procedures for Quimby-type breast implants using Ir-192 seeds encapsulated in nylon tubing. This system deviates in several important respects from the requirements of the standard brachytherapy systems. For double-plane implants, optimized values of the interplanar spacing are given for a range of implant sizes, along with the corresponding target dose rates for 1.0 mCi seeds. We also describe a modification of the angiocatheter implantation technique, which allows the radioactive sources to be secured in place by a magnetic cap and washer, thus greatly facilitating the removal of the sources at the end of treatment.

Brachytherapy↗
PubMed1980

Interstitial brachytherapy of primary brain tumors. Preliminary report.

Ten patients harboring inaccessible, slow-growing or recurrent malignant primary brain tumors were treated by the stereotaxic implantation of a radionuclide seed -- iridium-192 (192Ir) or gold-198 (198Au) -- either permanent or removable. The strength for 192Ir seeds was selected to deliver 10,000 to 12,000 rads to the periphery of the tumor, and that for 198Au seeds to deliver 4000 to 7500 rads. Three of the six patients treated with 192Ir showed objective responses lasting 8, 11, and 12 months, respectively; and one patient's disease stabilized for 18 months. Three of the four treated with 198Au showed responses lasting 5 months, 6 months, and 2 years, respectively. Because of the higher dose-rate attainable with 198Au, removable implants of this material are more effective against the faster-growing malignant tumors. Another radionuclide, iodine-125 (125I), is now being tested against brain tumors. The radioactivity of 125I is high; but because its gamma emission is less energetic by a factor of 10 than that of 198Au or 192Ir, its radiation field is concentrated within a radius of 2.5 cm or less. This low-energy gamma emission also makes it easier to protect medical personnel and the patients' families against the nuclide when 125I is used.

Adult↗
PubMed1975

Interstitial therapy suing non-absorbable (Ir192 nylon ribbon) and absrobable (I125 "Vicryl") suturing techniques.

Permanent and removable interstitial implantation techniques using absorbable and unabsorbable sutures are described. Most of these techniques can be performed in the clinic easily and quickly with basic instruments: needle holder, needle book, and hemoclips. Specifically, Ir192 (74-4 day half life, 300-610 keV, and 6.0 cm. hvl in tissue) nylon ribbon and I125 (60 day half life, 27-35 keV, and 2.0 cm. hvl in tissue) Vicryl sutures are described. A major advantage of the I125 over the Ir192 see (other than the fact that it can be permanently implanted and needs less radiation protection) is that the patient does not remain highly radioactive for as long a period due to hte extremely low I125 energy and may be allowed to leave the hospital. Both nuclides have the advantage of a long shelf life, making their use practical and economically feasible.

Humans↗
PubMed1985

The guide gutter or loop techniques of interstitial implantation and the Paris system of dosimetry.

The predictive dosimetry system for implants known as the Paris system can be used with either loops or hairpins. When using the guide gutter technique, implant geometry is predetermined by the inherent spacing and parallelism of the branches of the hairpins. When using loops, their branches should not be spaced too widely apart and should be parallel over an adequate distance to obtain a fairly regular dose distribution between them. The basic principles of implantation are the same as for rectilinear sources. Branches must be rectilinear, parallel, arranged so that their centers are located in the same plane (central plane). Adjacent branches must be equidistant from each other and the reference linear kerma rate (or the linear activity) must be uniform and identical for all sources. When these conditions are met, the dimensions of the treated volume (volume encompassed by the reference isodose surface with a value equal to 85% of the basal dose rate) can be estimated at the time of the implantation procedure. In practice, only a few relationships presented in this paper, with examples of application, must be known. Although, the Paris system permits forecasting the final dosimetry, the geometry of the implant must be verified and the dose calculated according to the implantation as actually achieved. The best method of checking the exact position of radioactive sources in an implant and determining the dose rate at any desired point is a reconstruction by computer program although alternative methods are occasionally appropriate.(ABSTRACT TRUNCATED AT 250 WORDS)

Brachytherapy↗
PubMed2004

High dose rate brachytherapy as prostate cancer monotherapy reduces toxicity compared to low dose rate palladium seeds.

PURPOSE: We evaluated the potential for differing acute and chronic toxicities between 2 monotherapy methods of image guided conformal brachytherapy, high dose rate (HDR) brachytherapy alone and low dose rate (LDR) permanent palladium seeds. MATERIALS AND METHODS: A total of 149 patients with biopsy proven, early stage prostate cancer were consecutively treated with interstitial brachytherapy as the sole method of treatment at William Beaumont Hospital between 1999 and 2001. Of the 149, 65 patients were treated with HDR using 192 iridium (192Ir), and 84 patients were treated with LDR using 103 palladium (103Pd). The majority of patients had clinical stage II, T1c or T2a disease, pretreatment prostate specific antigen less than 10 ng/ml and Gleason score 6 or less. Neoadjuvant hormones were used in 36% of patients for gland volume optimization. All treatments were performed transperineally with trans-rectal ultrasound guidance and fluoroscopy for verification of needle/seed positions. The HDR dose was 38 Gy delivered in 4 fractions, 2 times daily during 2 days. The LDR dose was 120 Gy. Acute and chronic toxicities were scored according to the Common Toxicity Criteria scale, version 2.0. RESULTS: Median followup for all patients was 35 months. The 2 treatment groups were well-balanced with respect to age, clinical stage, prostate specific antigen, Gleason score, use of neoadjuvant hormones, pretreatment genitourinary symptoms, implanted gland volume and length of followup. Biochemical control (American Society for Therapeutic Radiology and Oncology definition) was 97% and 98% for LDR and HDR, respectively. HDR brachytherapy alone was associated with decreased acute rates of grade 1 to 3 dysuria (67% versus 36%, p <0.001), urinary frequency/urgency (92% versus 54%, p <0.001) and rectal pain (20% versus 6%, p = 0.017). These differences remained significant when patients who received prior hormonal therapy were excluded from analysis. Selected chronic toxicities were also decreased with HDR, including long-term urinary frequency and urgency, 32% (HDR) vs 56% (103Pd), p = 0.004. There were no differences in the rates of chronic dysuria, urinary incontinence, retention or hematuria. Urethral stricture rates were 8% in the HDR alone group vs 3% for 103 Pd (p = 0.177). The 3-year actuarial impotence rate was 45% for the LDR group and only 16% for HDR. The majority of complications were grade 1. No grade 4 toxicities were encountered in either group. HDR decreased treatment cost by 19%. CONCLUSIONS: While HDR (192 iridium) and LDR (103Pd) monotherapy maintained the same biochemical control, the use of HDR brachytherapy as monotherapy was associated with decreased rates of acute urinary frequency, urgency, dysuria and rectal pain compared to LDR. Chronic urinary frequency, urgency and grade 2 rectal toxicities were also decreased with HDR. A dramatic decrease (66%) was noted in the rate of sexual impotency with HDR. In addition, patients treated with HDR did not remain radioactive after treatment. There was a decrease in cost from not purchasing seeds per patient. HDR monotherapy as prostate cancer treatment resulted in the same biochemical control with much lower toxicity. It is an accepted, convenient, cost-effective method of prostate brachytherapy for patients with favorable risk prostate cancer.

Adenocarcinoma↗
PubMed1996

Combined surgery and brachytherapy in the treatment of some cancers of the bladder (partial cystectomy and interstitial iridium-192).

Eighty-five bladder cancers were treated at the Urology Clinic of Nancy and the Centre Alexis Vautrin from 1975 to 1992 with short course preoperative radiation therapy (3 x 3.5 Gy), conservative surgery and brachytherapy by iridium-192. The tumours were classified according to the 1979 UICC pTNM classification. There were 27 pT1, 31 pT2 and 22 pT3, two pT4 and three pTx. The pT1-pT2 cases received only one brachytherapy (50 Gy at least) after the short course preoperative irradiation. The pT3 cases received only 30 Gy of brachytherapy and an external irradiation boost (generally 40 Gy to the node areas and 30 Gy to the tumour, but the dose varied during the time course). Surgery was often preceded by an endoscopic resection consisting of a tumoral resection or a partial cystectomy according to the localisation. The plastic vector tubes were put into place at the time of partial cystectomy. Until 1983 the radioactive wires were loaded into the vector tubes on the day following surgery, thereafter it was done one week later. The 85 patients were classified into two groups: 63 patients who were untreated previously and 22 patients who had received one or more endoscopic resections for recurrences. The median follow-up was 84 months. The local controls at 5 years were 78% in the first group versus 56% in the second group (p = 0.005) with an overall survival of 73 and 65%, respectively. The local control did not vary according to the differentiation (grade 1/2 vs. grade 3). The local control for pT1, pT2, pT3 was 85, 64 and 70% with a specific survival of 85, 76 and 72%, and an overall survival of 78, 66 and 66%. Among early complications, delay in healing of the bladder wall with subsequent vesico-cutaneous fistula depends mainly on the loading time of radioactive wires after surgery and is rare if the loading is delayed by one week. The late complications depend mostly on dosimetric factors. We found 24 grade 1, three grade 2, four grade 3 and one grade 4. The following factors are significant: the surface treated (> 14 cm2), a distance between the sources of more than 2 cm and, especially, activity of the wires of more than 2 mCi/cm (this factor was found in the five complications of grade 3 and 4), the other factors were not significant in univariate analyses.

Brachytherapy↗
PubMed1986

[Present status of brachytherapy].

High dose rate, remote-afterloading intracavitary irradiation (RALS) and low dose rate, interstitial irradiation were discussed. In Japan, RALS is now a standard treatment for uterine cervix carcinoma. In interstitial radiotherapy, radium sources, because of their poor conditions of protection and excessively long half-life, are being replaced by several new radioactive elements, such as 60Co, 125I, 125Cs and 192Ir. These have suitable characteristics for afterloading and safety protection. Among them 192Ir has become common source, not only for intraoral cancer, but also various other tumors including rectal, breast, and bile duct cancers.

Brachytherapy↗
PubMed1994

Verification of source position in interstitial and intralumenal brachytherapy.

In brachytherapy afterloading, the treatment is simulated using dummy sources. In this study, imaging during treatment was performed to see whether the radioactive sources accurately replaced the dummy sources. In low-dose rate afterloading (manually or remote controlled) X-ray radiography was applied for verification. In high dose rate afterloading, the radioactive source was visualised under remote controlled X-ray fluoroscopy. Differences between dummy and treatment source position were observed, justifying verification imaging in brachytherapy.

Brachytherapy↗
PubMed2003

Intraoperative dural irradiation by customized 192iridium and 90yttrium brachytherapy plaques.

PURPOSE: After vertebral or paravertebral tumor resection, tumor cells may remain on the dura. Because a tumoricidal dose is difficult to achieve using external beam radiotherapy without exceeding the spinal cord tolerance, we developed intraoperative applicators to deliver additional dose to the dura. METHODS AND MATERIALS: Eight patients with vertebral or paravertebral tumor underwent conformal external beam radiotherapy, tumor resection, and intraoperative radiotherapy to the dura involved by tumor. At surgery, vertebra, soft tissue, and epidural tumor were resected. A radioactive applicator plaque was placed on the dura to deliver 7.5-15 Gy, and then removed. Vertebral reconstruction and stabilization was completed. Chemotherapy was administered for large, high-grade sarcomas. RESULTS: We progressed through three plaque designs, initially (192)Ir, subsequently liquid (90)Y, and finally (90)Y foil in a semicylindrical polycarbonate plaque, in the treatment of 8 patients. The low-energy (90)Y beta-emissions provided a more attractive depth dose profile than that achievable with iridium and gave negligible staff radiation exposure. The (90)Y depth dose measured 29% at 2 mm and 9% at 4 mm from the surface of the foil plaque, with acceptable surface dose homogeneity. The average surface dose rate ranged from 18.7 to 47.6 cGy/min for the iridium plaques and 45.2 to 187.5 cGy/min for the (90)Y plaques. The treatments have been without acute or late neurologic complications. The disease of 6 of 8 patients was locally controlled at median potential follow-up of 24 months. CONCLUSIONS: The (90)Y foil applicator is technically elegant, easy to use, and superior to the earlier models. It has been incorporated into a protocol for spinal tumor treatment.

Brachytherapy↗
PubMed1983

Treatment of advanced cancer of the cervix with transperineal interstitial irradiation.

A pilot study using transperineal interstitial implantation to the parametrium in patients with locally advanced carcinoma of the cervix or with distorted anatomy is presented. Twenty-one consecutive patients (2 cervical stump Stage IB, 3 Stage IIB, 15 Stage IIIB, 1 Stage IVA) received one (12) or two (9) implants following 40-45 Gy whole pelvis external irradiation. In addition 8 patients underwent staging laparotomies concurrently with the first implant procedure. Control of the pelvic tumor was accomplished in 18 of 21 patients (85%) with a mean follow-up of 26 months (range 15 to 48 months). Seven patients (33%) developed long term complications (fistula 3, superficial necrosis of the vagina 1, severe proctitis or cystitis 3). Six of the complications occurred in 8 patients (75%) who had radioactive sources placed on the surface of the vaginal obturator as a substitute for the lack of tandem. In contrast, only 1 in the remaining 13 patients (8%) who did not have obturator sources placed, developed long term complications.

Adult↗
PubMed1985

Iridium afterloading curietherapy in the treatment of pediatric malignancies. The Institut Gustave Roussy experience.

Between 1972 and 1980, 58 children with malignant tumors underwent iridium 192 (192Ir) curietherapy at the Institut Gustave Roussy. Data from only 45 of them were reviewed (bilateral retinoblastoma and salvage procedures were excluded). The pathologic diagnosis was rhabdomyosarcoma in 75% of cases, yolk sac tumor in 13% of cases, malignant mesenchymoma in two cases, clear cell carcinoma in two cases, and undifferentiated sarcoma in one case. The two major sites were pelvis-perineum (64.5%) and head and neck (31%). The treatment was essentially based on a combination of chemotherapy, which was adapted to the histologic type of the tumor, and curietherapy. Partial surgery was carried out in certain cases, either before chemotherapy for diagnostic purposes, or after chemotherapy to remove infiltrative residual tumor. External beam radiotherapy was used in a few cases in lymph node irradiation. The radioactive material was 192Ir, using afterloading techniques, either intracavitary or interstitially or both. The tumor dose, calculated by computerized dosimetry, was 60 to 65 Gy delivered over 5 to 7 days in the majority of cases. Two patients were lost to follow-up. Thirty-five patients (78%) are alive with no evidence of disease after a mean follow-up period of 5 years. Eight patients died, one of complications related to chemotherapy and seven of the evolution of their disease. The late-complication rate, studied in 33 patients with a minimum follow-up period of 3 years, is 18% (6/33). Curietherapy seems to be a preferable conservative treatment in children with localized and accessible malignant tumors.

Adolescent↗
PubMedDate not supplied

Review of endovascular brachytherapy physics for prevention of restenosis.

Intraluminal irradiation of coronary and peripheral arteries has been shown to reduce neointimal hyperplasia following balloon angioplasty, thereby inhibiting restenosis. Several irradiation techniques are being investigated, including temporary intravascular insertion of high activity gamma- or beta-emitting seeds and wires; inflation of dilatation balloon catheter with radioactive liquid or gas; insertion of miniature x-ray tubes via coronary catheters; permanent implantation of radioactive stents; and postangioplasty fractionated external beam irradiation. Unlike conventional brachytherapy, intravascular treatment of restenosis requires accurate knowledge of dose at distances of 0.5-5 mm from the radioactive source. This requirement presents special problems with regard to source calibration and dose specification, because dose gradients at such close distances from a radioactive source are extremely large. This makes it virtually impossible to define the characteristics of an ideal radiation source without some knowledge of the location and radiosensitivity of the target tissues, plus the radiotolerance of normal tissues. Hence, the current debate over whether beta or gamma sources are to be preferred. Imprecise knowledge of dose-volume effects for coronary arteries, plus uncertainties in the biological time sequencing of restenosis fuel a second debate on whether external beam treatments may be efficacious, and whether or not permanent radioactive stents may prove superior to high dose, single fraction brachytherapy. We review here the dosimetric properties of the various irradiation techniques and isotopes that have been proposed, including aspects of radiation safety, dose homogeneity, and practical aspects of source delivery.

Animals↗
PubMed2004

Consequences of radiation accidents.

Radiation injury attributable to radiotherapy is a topic that has attracted ample attention in the literature, especially in a vast number of publications in plastic surgery. However, the literature is clearly devoid of compilations regarding the effects of ionized radiation accidents. A case of a radiation accident is presented. It is nearly impossible to anticipate the extent of effects of external irradiation of the skin and subcutaneous tissues. The initially healed area should be expected to show late recurrent necrosis. Patients exposed to ionized external irradiation are no longer radioactive and can be treated as ordinary patients. However, these patients should be followed closely for years, keeping in mind the onset of late radiation effects like skin necrosis in various parts of the body, skin and other organ cancers, leukemia, infertility, hypothyroidism, and cataracts.

Adult↗
PubMedDate not supplied

Interstitial-implant radiotherapy in upper-aerodigestive-tract malignancy.

In the treatment of upper-aerodigestive-tract malignancy, interstitial-implant radiotherapy differs in several physical and biologic respects from conventional external-beam therapy: unlike external-beam therapy, it can deliver a high central dose with a rapid fall-off, which overcomes the central hypoxic resistance effect and yet greatly improves normal tissue tolerance. External-beam and interstitial-implant therapy can also be combined to the patient's benefit; in many cases, this combination offers advantages over external-beam therapy alone, preoperative external-beam therapy, or aggressive surgery. The recent upsurge of interest in this modality has come about because of three developments: more suitable radioactive sources, after-loading, and computerized dosimetry. The early results in upper-aerodigestive-tract malignancy, both as primary and as salvage therapy, are promising; but the precise role of this treatment in our therapeutic armamentarium remains to be established.

Brachytherapy↗
PubMed1997

Physics and safety aspects of a coronary irradiation pilot study to inhibit restenosis using manually loaded 192Ir ribbons.

Radiation therapy has been successfully used in controlling some forms of benign tissue growth. A pilot study has been launched to evaluate the usefulness of localized radiation therapy in reducing restenosis after coronary angioplasty. In this randomized, double-blind study, patients with known restenosis received balloon angioplasty or additional stent implantation and were then randomized to receive either radiation or placebo treatment. Active sources consisted of 192Ir in the form of cylindrical seeds (0.3 x 0.05 cm). The seeds are embedded in a nylon ribbon. The nylon ribbon is passed through an indwelling coronary catheter. For this pilot trial, radioactive sources were exposed to blood elements and, therefore, required sterilization. A method of sterilization is described. A working team was developed to perform coronary radiation procedures at our institution. A description of the procedure is provided.

Angioplasty, Balloon, Coronary↗
PubMed2005

Fluorescent screen for high-dose-rate (HDR) brachytherapy quality assurance.

This article describes apparatus for quickly checking the positioning and dwell times of a high-dose-rate (HDR) afterloader as part of daily quality assurance (QA). A groove was milled into an aluminum plate to align an HDR applicator, and fluorescent screens were placed on either side of the groove. Lines were drawn at the fluorescent screen corresponding to distances to which the radioactive source should travel in our daily QA treatment protocol. By dimming the room lights, the fluorescence from the source was seen with a closed-circuit video camera, and the positioning accuracy and dwell time of the source could be efficiently verified. Not only is this an excellent QA tool, but it also provides good training for radiation therapists and other HDR professionals.

Brachytherapy↗