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At least 19 recordsLinked to original sources
PubMed2003

Iridium-catalyzed borylation of benzene with diboron. Theoretical elucidation of catalytic cycle including unusual iridium(v) intermediate.

Iridium-catalyzed borylation of benzene with diboron was theoretically investigated with the DFT method, where an iridium(I) boryl complex, Ir(Beg)(NN) 1, and an iridium(III) tris(boryl) complex, Ir(Beg)(3)(NN) 14, (eg (ethyleneglycolato) = -OCH(2)CH(2)O-, NN = HN=CHCH=NH (diim) or 2,2'-bipyridine (bpy)) were adopted as models of active species and B(2)(eg)(2) was adopted as a model of bis(pinacolato)diboron (pinacolato = -OCMe(2)CMe(2)O-). Oxidative addition of a benzene C-H sigma-bond to 1 takes place with an activation barrier (E(a)) of 11.2 kcal/mol, followed by reductive elimination of phenylborane, Ph-Beg, from Ir(Beg)(H)(Ph)(diim) with an activation barrier of 15.6 kcal/mol. Though the oxidative addition and the reductive elimination occur with moderate activation barriers, B(2)(eg)(2) much more easily reacts with 1 to afford 14 than does benzene, of which the activation barrier is very small (2.9 kcal/mol). Oxidative addition of the benzene C-H sigma-bond to 14 occurs with a moderate activation barrier of 24.2 kcal/mol to afford an unusual seven-coordinate iridium(V) complex, Ir(H)(Ph)(Beg)(3)(bpy) 16. From this complex, phenylborane Ph-Beg is produced through the reductive elimination with concomitant formation of IrH(Beg)(2)(bpy) 17, where the activation barrier is 4.9 kcal/mol. Complex 17 further reacts with diboron to form Ir(H)(Beg)(4)(bpy) (E(a) = 8.0 kcal/mol), followed by the reductive elimination of borane H-Beg (E(a) = 2.6 kcal/mol) to regenerate Ir(Beg)(3)(bpy), when diboron exists in excess in the reaction solution. After consumption of diboron, IrH(Beg)(2)(bpy) reacts with borane, H-Beg, to form Ir(H)(2)(Beg)(3) (E(a) = 21.3 kcal/mol) followed by the reductive elimination of H(2), to regenerate Ir(Beg)(3)(bpy) with concomitant formation of H(2). Formation of the iridium(III) tris(boryl) complex 14 from IrCl(diim) and diboron was also theoretically investigated; IrCl(diim) undergoes two steps of oxidative addition of diboron to afford a seven-coordinate iridium(V) complex, IrCl(Beg)(4)(NN), from which the reductive elimination of Cl-Beg takes place easily to afford 14. From these results, it should be clearly concluded that the iridium(III) tris(boryl) complex is an active species and an unusual iridium(V) species is involved as a key intermediate in the reaction. Detailed discussion is presented on the full catalytic cycle and the importance of a seven-coordinate iridium(V) intermediate.

Journal Article↗
PubMed2004

Isolation and characterization of iridium(III) and iridium(V) complexes of 2-(arylazo)pyridine and studies of amine fusion reactions at the coordinated diazo-ligand.

The reaction of IrCl3.3H2O with 2-(arylazo)pyridine (HL1) in boiling methanol has afforded [Ir(III)Cl2(L1)(HL1)](1) and [Ir(V)Cl4(HL1)]Cl (2). In complex , one of the two ligands [L1]- is orthometallated via coordination of an ortho-carbon of the aryl ring of [L1]- and one of the two azo nitrogens to form a five-membered chelate. X-Ray crystal structures of the two representative complexes, viz. 1a and 2a, have been solved. Notably, the Ir-N length (2.140(3) A)trans to the Ir-C bond in 1a is appreciably longer than the other three Ir-N lengths present in the same molecule. The N-N lengths in these two compounds lie close to that observed in the uncoordinated ligand. Thorough NMR studies were made to authenticate the carbon-bonded structure of compound 1a. In its 13C NMR spectrum, the resonance near delta 148 is assigned to the carbon bonded to the iridium metal center. UV-visible spectra along with the redox properties of these complexes are reported. The iridium(V) complex, 2 showed a reversible response near 1.40 V, presumably due to the iridium(V)-iridium(VI) couple. Several reductive responses at cathodic potentials, due to ligand reductions, were also observed. Metal promoted aromatic ring amination reactions at the coordinated HL1 ligand in complexes 1 and 2 were investigated. The products were characterized using X-ray diffraction.

Journal Article↗
PubMed2004

Stoichiometric and catalytic H/D incorporation by cationic iridium complexes: a common monohydrido-iridium intermediate.

A mechanistic study of the stoichiometric and catalytic H/D exchange reactions involving cationic iridium complexes is presented. Strong evidence suggests that both stoichiometric and catalytic reactions proceed via a monohydrido-iridium species. Stoichiometric deuterium incorporation reactions introduce multiple deuterium atoms into the organic products when aryliridium compounds CpPMe(3)Ir(C(6)H(4)X)(OTf) (X = H, o-CH(3), m-CH(3), p-CH(3)) react with D(2). Multiple deuteration occurs at the unhindered positions (para and meta) of toluene, when X = CH(3). The multiple-deuteration pathway is suppressed in the presence of an excess of the coordinating ligand, CH(3)CN. The compound CpPMe(3)IrH(OTf) (1-OTf) is observed in low-temperature, stoichiometric experiments to support a monohydrido-iridium intermediate that is responsible for catalyzing multiple deuteration in the stoichiometric system. When paired with acetone-d(6)(), [CpPMe(3)IrH(3)][OTf] (4) catalytically deuterates a wide range of substrates with a variety of functional groups. Catalyst 4 decomposes to [CpPMe(3)Ir(eta(3)-CH(2)C(OH)CH(2))][OTf] (19) in acetone and to [CpPMe(3)IrH(CO)][OTf] (1-CO) in CH(3)OH. The catalytic H/D exchange reaction is not catalyzed by simple H(+) transfer, but instead proceeds by a reversible C-H bond activation mechanism.

Alcohols↗
PubMed1995

Interstitial hyperthermia and iridium-192 treatment alone vs. interstitial iridium-192 treatment/hyperthermia and low dose cisplatinum infusion in the treatment of locally advanced head and neck malignancies.

PURPOSE: To determine whether the addition of low dose platinum infusional chemotherapy adds to the effectiveness of interstitial hyperthermia/iridium-192 management of locally advanced head and neck malignancies. METHODS AND MATERIALS: From 1987 to 1993, 36 patients with locally advanced head and neck malignancies were treated locally with interstitial hyperthermia and iridium-192 as part or all of their management. Twenty-two of the above-mentioned patients also received low dose infusional cisplatinum chemotherapy at 20 mg/M2 per day during the time of the implant. No patient received greater than 100 mg/M2 total dose. Implant times ranged from 38.5 to 134 h and total doses delivered with the radiation implants ranged from 15 to 39.9 Gy. Average implant volume was 50 cc. Twenty-three patients received external beam irradiation supplementation in a dose range from 25.2 to 64 Gy. RESULTS: Median follow-up for the entire group was 8, months with 7 months for the chemotherapy group vs. 12 months for the no-chemotherapy group. Freedom from relapse rates for the chemotherapy group vs. the no-chemotherapy group were 70% at 41 months vs. 63% at 60 months, p = not significant (p = NS). Overall survival by Life Table Analysis was 28% for the chemotherapy group at 41 months vs. 31% for the no-chemotherapy group at 60 months (p = NS). Complete response (CR) rates were 93% for the chemotherapy group vs. 86% for the no-chemotherapy group. Seven patients in the chemotherapy group had recurrent disease and four patients in the no-chemotherapy group were being treated for recurrent disease. Complication rates were similar in both groups, with two patients in the chemotherapy arm requiring hyperbaric oxygen treatments and one patient in the no-chemotherapy arm requiring hyperbaric oxygen treatments (for soft tissue necrosis). CONCLUSION: It appears that low dose platinum infusional chemotherapy can be added safely to patients receiving interstitial iridium-192 implants along with interstitial hyperthermia for head and neck malignancies. Although there appears to be a trend toward better freedom from relapse by adding chemotherapy, a larger trial and longer follow-up will be necessary to prove statistical significance. Further research in these areas is recommended in the form of a randomized prospective study.

Brachytherapy↗
PubMed2005

Mechanism of the mild functionalization of arenes by diboron reagents catalyzed by iridium complexes. Intermediacy and chemistry of bipyridine-ligated iridium trisboryl complexes.

This paper describes mechanistic studies on the functionalization of arenes with the diboron reagent B(2)pin(2) (bis-pinacolato diborane(4)) catalyzed by the combination of 4,4'-di-tert-butylbipyridine (dtbpy) and olefin-ligated iridium halide or olefin-ligated iridium alkoxide complexes. This work identifies the catalyst resting state as [Ir(dtbpy)(COE)(Bpin)(3)] (COE = cyclooctene, Bpin = 4,4,5,5-tetramethyl-1,3,2-dioxaborolanyl). [Ir(dtbpy)(COE)(Bpin)(3)] was prepared by independent synthesis in high yield from [Ir(COD)(OMe)](2), dtbpy, COE, and HBpin. This complex is formed in low yield from [Ir(COD)(OMe)](2), dtbpy, COE, and B(2)pin(2). Kinetic studies show that this complex reacts with arenes after reversible dissociation of COE. An alternative mechanism in which the arene reacts with the Ir(I) complex [Ir(dtbpy)Bpin] after dissociation of COE and reductive elimination of B(2)pin(2) does not occur to a measurable extent. The reaction of [Ir(dtbpy)(COE)(Bpin)(3)] with arenes and the catalytic reaction of B(2)pin(2) with arenes catalyzed by [Ir(COD)(OMe)](2) and dtbpy occur faster with electron-poor arenes than with electron-rich arenes. However, both the stoichiometric and catalytic reactions also occur faster with the electron-rich heteroarenes thiophene and furan than with arenes, perhaps because eta(2)-heteroarene complexes are more stable than the eta(2)-arene complexes and the eta(2)-heteroarene or arene complexes are intermediates that precede oxidative addition. Kinetic studies on the catalytic reaction show that [Ir(dtbpy)(COE)(Bpin)(3)] enters the catalytic cycle by dissociation of COE, and a comparison of the kinetic isotope effects of the catalytic and stoichiometric reactions shows that the reactive intermediate [Ir(dtbpy)(Bpin)(3)] cleaves the arene C-H bond. The barriers for ligand exchange and C-H activation allow an experimental assessment of several conclusions drawn from computational work. Most generally, our results corroborate the conclusion that C-H bond cleavage is turnover-limiting, but the experimental barrier for this bond cleavage is much lower than the calculated barrier.

Benzene Derivatives↗
PubMed1981

An iridium-iridium oxide electrode for in vivo monitoring of blood pH changes.

An iridium-iridium oxide electrode for in vivo monitoring of blood pH changes is described. Because of its small size, sensitivity, flexibility, strength and fast response, this electrode is suitable for acute implantation even in the small vessels of animals such as rats or guinea pigs, allowing continuous pH monitoring anywhere in the central arteries or veins. Excellent noise-free records have been obtained in the in vivo experiments in animals.

Animals↗
PubMed1996

Photochemistry of Dihydrido(hydrotris(3,5-dimethylpyrazolyl)borato)(Z-cyclooctene)iridium. Synthetic Intermediates and Mechanism of the Photochemical Formation of Hydridophenyl(hydrotris(3,5-dimethylpyrazolyl)borato)(trimethyl phosphite)iridium.

The photolysis of a benzene solution of [Tp(Me2)IrH(2)(COE)], 1 (Tp(Me2) = hydrotris(3,5-dimethylpyrazolyl)borate, COE = Z-cyclooctene), in the presence of P(OMe)(3), gives the stable novel complex [Tp(Me2)IrH(C(6)H(5))(P(OMe)(3))], 3a. The photochemical syntheses of [Tp(Me2)IrH(2)(P(OMe)(3))], from 1 and P(OMe)(3) in diethyl ether, and [Tp(Me2)IrH(2)(CH(2)=CHCOO(t)Bu)], from 1 in tert-butyl acrylate, are also reported. The above reactions and several experiments using C(6)D(6) and P(OCD(3))(3) show that, in all cases, the primary photoproduct is the 16-electron, five-coordinate iridium(III) intermediate {Tp(Me2)IrH(2)}, 6a, produced by loss of COE from 1. The above experiments also allow the postulation of a mechanistic pathway for the formation of 3a which involves the oxidative addition of an aromatic C-H bond by 6a. Furthemore, the photochemical reaction of 1 in the presence of P(OCD(3))(3) shows that, under the reaction conditions used, oxidative addition of C-H bonds of P(OMe)(3) and of coordinated Tp(Me2)-ligands, presumably, to the intermediates 6a and {Tp(Me2)IrH(C(6)H(5))}, also occurs. Thus, coordinatively unsaturated iridium(III) species readily activate C-H bonds.

Journal Article↗
PubMed1997

Hydrotris(pyrazolyl)borato Cycloocta-1,5-diene Complexes of Iridium(I): Synthetic Studies and Equilibria in Solution. X-ray Crystal Structures of a Four- and a Five-Coordinate Iridium(I) Hydrotris(pyrazolyl)borato Complex.

The compounds [Tp(3R,4R,5R)Ir(COD)] (COD = cycloocta-1,5-diene; Tp(3R,4R,5R) = hydrotris(pyrazolyl)borate (1), hydrotris(3-methylpyrazolyl)borate (2), hydrotris(3-isopropylpyrazolyl)borate (3), hydrotris(3,5-dimethylpyrazolyl)borate, hydrotris(3-(trifluoromethyl)-5-methylpyrazolyl)borate, hydrotris(3-phenyl-5-methylpyrazolyl)borate, hydrotris(3,5-diisopropylpyrazolyl)borate, hydrotris(3,4,5-trimethylpyrazolyl)borate, hydrotris(4-chloro-3,5-dimethylpyrazolyl)borate (9), hydrotris(4-bromo-3,5-dimethylpyrazolyl)borate) were prepared and characterized by IR and NMR spectroscopy. The X-ray crystal structure of 9.2MeOH (triclinic, space group P&onemacr; (No. 2); a = 10.044(1) Å, b = 11.186(2) Å, c = 15.499(3) Å; alpha = 77.90(1) degrees, beta = 73.23(1) degrees, gamma = 66.89(1) degrees; Z = 2; R = 0.0276 for 2469 observed reflections) shows that iridium is four-coordinate with an eta(2)-hydrotris(pyrazolyl)borate. The X-ray crystal structure of 1 (triclinic, space group P&onemacr; (No. 2); a = 7.345(1) Å, b = 7.645(1) Å, c = 15.893(5) Å; alpha = 103.17(4) degrees, beta = 90.30(2) degrees, gamma = 93.50(3) degrees; Z = 2; R = 0.0433 for 2606 observed reflections) shows that iridium is five-coordinate with an eta(3)-bonded tris(pyrazolyl)borate. Equilibria between corresponding four- (eta(2)-Tp(3R,4R,5R)) and five-coordinate (eta(3)-Tp(3R,4R,5R)) species of all the complexes are established in solution. The complex containing the ligand HB(Pz(3Me))(3) (Pz = pyrazolyl group) (2) rearranged first to the corresponding complex with HB(Pz(3Me))(2)(Pz(5Me)) and then into that with HB(Pz(3Me))(Pz(5Me))(2). However, 3, which contains HB(Pz(3)()i(Pr))(3), gave only the complex with coordinated HB(Pz(3)()i(Pr))(2)(Pz(5)()i(Pr)).

Journal Article↗
PubMed2005

In vitro comparison of the charge-injection limits of activated iridium oxide (AIROF) and platinum-iridium microelectrodes.

The charge-injection limits of activated iridium oxide electrodes (AIROF) and PtIr microelectrodes with similar geometric area and shape have been compared in vitro using a stimulation waveform that delivers cathodal current pulses with current-limited control of the electrode bias potential in the interpulse period. Charge-injection limits were compared over a bias range of 0.1-0.7 V (versus Ag/AgCl) and pulse frequencies of 20, 50, and 100 Hz. The AIROF was capable of injecting between 4 and 10 times the charge of the PtIr electrode, with a maximum value of 3.9 mC/cm2 obtained at a 0.7 V bias and 20 Hz frequency.

Electric Impedance↗
PubMed1995

Contact urticaria with anaphylactic reactions caused by occupational exposure to iridium salt.

This paper presents the case of a non-smoking and non-atopic male, exposed to iridium chloride at work, who developed respiratory tract symptoms and contact urticaria. Application of iridium salt to normal skin caused contact urticaria. An iridium chloride prick test showed a positive reaction and a scratch test produced anaphylactoid reactions. Platinum salt allergy was excluded through prick testing with hexachloroplatinate solution. There is no previous report describing a case where an individual has a positive prick test reaction to iridium salts and simultaneously a negative one to platinum salts. The results are interpreted as immediate-type hypersensitivity (Type I allergy?) to iridium salt. The route of sensitization was probably through the airways. Further testing showed that iridium salt allergy could persist for at least 18 months after exposure ceases. 14 employees at the same factory were prick tested with iridium and platinum salts with negative results. Prick testing is recommended as a method of first choice when investigating a person with suspected iridium salt allergy.

Adult↗
PubMed1989

Endoscopic management of inoperable cholangiocarcinoma using iridium-192.

We report a well tolerated endoscopic technique of administering intraluminal radiotherapy to 14 patients with inoperable cholangiocarcinoma, in which the iridium-192 wire source was inserted down a nasobiliary catheter placed within a previously inserted endoscopic biliary prosthesis, thus allowing bile flow to continue during treatment. Radiotherapy was commenced 2 weeks after biliary decompression, when the median serum bilirubin level had fallen from 213 to 34 mumol/l. A total radiation dose of 6000 cGy at 0.5 cm from the source was administered over a median of 85 h (range 77-116 h). In four patients there was a transient increase in serum bilirubin during iridium treatment and, in two cases (14 per cent), this was associated with mild cholangitis. Both cases resolved rapidly once the iridium wire and nasobiliary catheter were removed. The median hospital stay after treatment was 2.5 days (range 0-28 days). The late complications associated with stent blockage were minimized by routinely changing stents at 4-6 monthly intervals; ten of the patients have so far undergone from one to five (median three) stent changes. Five patients have died at 3.6-8.2 months (median 4.8 months) following iridium treatment; four had extensive type III hilar lesions at diagnosis. Nine patients are still alive at 5.4-31.0 months (median 16.4 months). The overall median survival after iridium therapy is 10.5 months. This technique of endoscopic biliary decompression before internal iridium administration minimizes complications by allowing biliary drainage during treatment. The role of this treatment in patients with inoperable cholangiocarcinoma awaits the results of randomized, controlled trials.

Adenoma, Bile Duct↗
PubMed1992

A new re-entrant ionization chamber for the calibration of iridium-192 high dose rate sources.

A re-entrant (well-type) ionization chamber has been designed and fabricated at the University of Wisconsin for use with iridium-192 high dose-rate (HDR) remote after-loading brachytherapy devices. The chamber was designed to provide an ionization current of about 10(-8) ampere with a nominal 10 curie iridium-192 source. A narrow opening is provided into the sensitive volume of the chamber to insert a Nucletron MicroSelectron catheter, or catheters with similar diameters from other HDR manufacturers. The chamber exhibits a flat response (+/- 0.1%) for any source position within +/-4 mm of the chamber center. A 300 volt chamber bias yields a 99.96% ion collection efficiency. The chamber is capable of being calibrated directly with an iridium-192 source which has in turn been calibrated with thimble-type ion chambers. Reproducibility for readings in the current mode for 10 consecutive insertions of the MicroSelectron iridium-192 HDR source is within 0.02% or less. Two thimble chambers calibrated by the U.S. National Institute of Standards and Technology provide calibration traceability of iridium-192 HDR sources and re-entrant chambers to a primary national standards laboratory. Results of activity measurements of 6 commercial iridium-192 HDR sources are reported.

Calibration↗
PubMed1993

Place of Iridium 192 implantation in definitive irradiation of faucial arch squamous cell carcinomas.

PURPOSE: We have reviewed the results of 165 T1 and T2 squamous cell carcinomas of the faucial arch treated by definitive irradiation including or not Iridium 192 brachytherapy to ascertain whether a significant relationship existed between Iridium implantation, local control, complications, and survival. METHODS AND MATERIALS: From March 1971 to November 1990, 58 T1 and 107 T2 (NO: 107/165; N1: 30/165; N2: 9/165; N3: 19/165) biopsy proven squamous cell carcinomas of the tonsillar region (104/165) and the soft palate and uvula (61/165) were treated in Henri Mondor Hospital by definitive irradiation with curative intent. From 1971 to 1981 (period 1), only guide gutter technique was available, so that implants were reserved for small tumors: patients were either managed by definitive telecobaltherapy to tumor site and neck node areas (Group 1; n = 48; mean dose: 70 Gy; confidence interval: +/- 5.5; 5 fractions of 1.8 Gy per week) or by exclusive Iridium implant (Group 2; n = 11; all T1NO; 64 Gy +/- 4.8) or by a combination of external beam radiation therapy to tumor site and neck nodes areas and Iridium implant (Group 3; n = 40). In 1981 (Period 2), a new plastic tube technique, which enables implantation of larger areas, was introduced in the department and all patients (Group 4; n = 66) were then managed by external radiation therapy (Group 3 + 4: 47 Gy +/- 4.3) followed by an Iridium implant (31 Gy +/- 10.5). Clinically positive neck nodes either received additional external dose with electrons or were excised. RESULTS: Overall 5-year survival (Kaplan Meier) was 21%, 50.5%, and 60% in groups 1, 2, and 3 + 4, respectively (p < 0.001, log rank). Five-year local control was 58%, 100%, and 91%, respectively (p < 0.001). Five-year necrosis rate was 4.5%, 20.5% and 18%, respectively (N.S.). Comparison of results between the two periods of the study (Group 1 + 2 + 3 vs. group 4) show that these two groups are statistically comparable according to site and size of tumor and N status and that both local control (77% vs. 94% at 5 years; p < 0.01) and disease-free survival (56% vs. 71%; p = 0.03) were improved after 1980, while there was a trend to an increase in overall survival (42% vs. 53% at 5 years; p = 0.08); nodal control (86% vs. 95% at 5 years), and necrosis rate (11% vs. 20% at 5 years) were not modified. Multivariate analysis showed that both local control (p < 0.0001) and overall survival (p < 0.0001) were improved when tumor was implanted. CONCLUSION: We recommend then to treat T1 and T2 squamous cell carcinomas of the faucial arch by external radiation therapy to tumor site and neck areas (45 Gy/25 fractions/5 weeks) followed by a 30 Gy Iridium implant and, for patients with clinically positive nodes, either a further 25-30 Gy electron beam irradiation to the nodes or neck node dissection.

Brachytherapy↗
PubMed1993

The use of iodine-125 seeds as a substitute for iridium-192 seeds in temporary interstitial breast implants.

PURPOSE: We have previously reported that the use of iodine-125 seeds in temporary plastic tube interstitial implants may be more advantageous than iridium-192 seeds due to less patient and personnel radiation exposure, reduced shielding requirements, and significant dosimetric advantages. The impact of this isotope on the rate of local control and cosmetic outcome in patients with early stage breast cancer treated with interstitial implants for their irradiation "boost" remains to be defined. METHODS AND MATERIALS: We reviewed the treatment outcome of 402 consecutive cases of Stage I and II breast cancer undergoing breast conserving therapy between 1/1/80 and 12/31/87. All patients underwent excisional biopsy and received 45-50 Gy to the entire breast followed by a boost to the tumor bed using either electrons (104 patients), photons (15 patients), or an interstitial implant with either iridium-192 (197 patients) or iodine-125 (86 patients) to at least 60 Gy. Iodine-125 implants were primarily performed in patients with significant risk factors for local recurrence (71%) or in patients with large breasts (17%). Local tumor control and cosmetic outcome were assessed and contrasted between patients boosted with each modality. RESULTS: With a median follow-up of 59.3 months, 18 (4.5%) patients developed a recurrence of the tumor in the treated breast (4.4% 5-year actuarial rate). No statistically significant differences in the 5-year actuarial rate of local recurrence were noted between patients boosted with either iodine-125 (3.0%), iridium-192 (3.8%), electrons (5.4%), or photons (0%). Likewise, no significant differences in the percentage of patients obtaining good/excellent cosmetic results were noted between iodine-125 (93%), iridium-192 (88%), electrons (90%), or photons (82%). CONCLUSION: We conclude that patients with Stage I and II breast cancer undergoing breast conserving therapy and judged to be candidates for boosts with interstitial implants can be effectively treated with iodine-125 seeds. Use of this isotope results in less patient and personnel irradiation exposure and a better dose distribution than iridium-192, since dose optimization can be routinely employed. Overall, local control and cosmetic outcome have been excellent and are similar to either iridium-192, electrons, or photons.

Brachytherapy↗
PubMed1993

Carcinoma of the penis: a retrospective review of treatment with iridium mould and external beam irradiation.

This paper is a retrospective review of the treatment of carcinoma of the penis with radiotherapy alone over a 30-year period from 1960-1990 at The Royal London Hospital. During that time, 44 patients aged 31-85 years (mean 63) underwent treatment in our department, all of whom had histologically proven squamous carcinoma. Patients initially treated by surgery and those treated with combined surgery and radiotherapy were excluded from analysis. Twenty-four patients were treated by an iridium mould, and 20 by external beam irradiation. There were 67% complete responses; 79% for the patients treated by an iridium mould, 53% for those treated by external beam irradiation, although this difference between the two treatment groups was due to a more favourable stage distribution in the iridium group. Actuarial 2-, 5- and 10-year overall survivals were 87.9%, 85.1% and 72.3% respectively, with no significant difference between the iridium and external beam groups. For Stage I patients, the response rates and actuarial penile disease free survivals were comparable for the iridium and external beam groups. Urethral stricture was recorded in 10% of those treated by external beam irradiation and 13% of those treated by iridium mould. These results confirm that conservative treatment of carcinoma of the penis with radical radiotherapy allows preservation of a functioning penis with acceptable morbidity and a high proportion of long term survivors when surgery is used for salvage of locoregional relapse.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗