Pseudo-Hermitian anti-Hermitian ensemble of Gaussian matrices.

It is shown that the ensemble of pseudo-Hermitian Gaussian matrices recently introduced gives rise in a certain limit to an ensemble of anti-Hermitian matrices whose eigenvalues have properties directly related to those of the chiral ensemble of random matrices.

Pseudo-Hermitian ensemble of random Gaussian matrices.

It is shown how pseudo-Hermiticity, a necessary condition satisfied by operators of PT symmetric systems can be introduced in the three Gaussian classes of random matrix theory. The model describes transitions from real eigenvalues to a situation in which, apart from a residual number, the eigenvalues are complex conjugate.

Comparative dosimetry between iridium wires and seed ribbons.

We have undertaken a computer study that explores the conditions under which seed ribbons may replace iridium 192 wires in the Paris System. Compared with continuous iridium 192 wires, seed ribbons demonstrate greater inhomogeneity and loss of flexibility, simplicity, and other advantages. Nonetheless, we have defined the conditions where seed ribbons may be used in the Paris System to give satisfactory dose distributions and acceptable levels of heterogeneity within any given implant volume. These conditions include seed length, spacing between seeds, number of seeds per ribbon, and geometric arrangement of ribbons.

Intracavitary irradiation of carcinomas of the uterus and cervix: the Créteil method.

The Créteil method is a logical and simple system for intracavitary therapy of cervical and uterine cancer. The system is based on the use of a plastic cervico-vaginal moulage loaded with 0.5 mm diameter iridium 192 wire sources. The dimensions of both the moulage and the sources correspond to the size of the cervix being treated according to precisely defined relationships. The dose is specified on a reference isodose of a "fixed" value enclosing the pear-shaped target volume whose dimensions depend on the geometry of the sources. Source geometry in turn, depends on the size of the cervix. Thus, the dimensions of the target volume can be accurately predicted at the time of the application. Furthermore, treatment can be performed in a single application, with all sources having the same linear reference air kerma rate (or activity). Radioprotective measures are simple but effective and the patient is not subjected to the restrictions imposed by attachment to an after-loading apparatus. Our clinical results for early Stage T1 and T2a cervical tumors show excellent local control without major treatment complications or long term sequelae.

The indications for total cutaneous electron beam radiation therapy of mycosis fungoides.

From 1977 to 1984, we treated 34 patients with mycosis fungoides and 9 patients with B cutaneous lymphomas. Eighteen patients with mycosis fungoides were treated with total skin electron irradiation (TSEI) and had a minimum follow-up of 15 months (range 15 months to 7 years). The lowest electron energy of the linear accelerator was 8 MeV therefore we placed a plexiglas screen between the patient and the machine; the resulting electron energy was 4 MeV. The total dose was 30 Gy delivered in 12 fractions over 40 days. There were 8 males and 10 females. The median age was 48 years (ranging from 13 to 78 years). All patients were staged as follows: Stage A = superficial lesions covering less than 50% of the body surface; Stage B = superficial lesions covering more than 50% of the body surface; Stage C = tumors involving the skin, lymph nodes and/or visceral organs. Five patients with Stage A (5/5) and 5 patients with Stage B (5/5) had a complete remission, 1 stage A patient relapsed 6 months after completion of treatment. All the Stage B patients recurred between 3 and 15 months. The recurrences were localized to the skin and were well controlled with topical nitrogen mustard or puvatherapy. Among the Stage C patients, 3 did not respond to treatment and died of their disease; the remaining 5 patients achieved complete remission but they all relapsed from 2 to 9 months following completion of treatment. The median follow-up was 32 months and the average time for relapse was 6.5 months. All relapses except one (15 months) occurred within the first year. We feel that total skin electron irradiation is indicated in Stage A and B patients. However, we feel Stage C patients should receive TSEI for palliative purposes only.

Prognostic factors of local outcome for T1, T2 carcinomas of oral tongue treated by iridium 192 implantation.

The results of Iridium 192 implantation for 121 node negative T1 or T2 squamous carcinomas of mobile tongue were reviewed to look for predictors of local control and necrosis. Age, sex, total dose, dose rate, linear activity, and intersource spacing were examined. Minimum follow-up was 2 years but no patient with local recurrence or necrosis was excluded. There were 57 T1N0 tumors, 45 T2aN0 (2.1-3.0 cm), and 19 T2bN0 (3.1-4.0 cm). Local failures occurred in 14% of T1, 11% of T2a, and 26% of T2b. Univariate analysis showed that local control increased with increasing dose (55-60 Gy: 73%; 65-75 Gy: 92%, p = 0.005), whereas multivariate analysis revealed both sex and total dose to be significant. Radiation necrosis occurred in 17% of T1, 29% of T2a, and 47% of T2b (p = 0.034). Half were limited to soft tissue and the majority healed with conservative management. Univariate analysis showed that necrosis increased with increasing dose (55-60 Gy: 16%; 65-75 Gy: 33%, p = 0.037), as well as increasing dose rate, linear activity, and intersource spacing. With multivariate analysis only stage, dose rate, and spacing remained predictive of necrosis. Total dose was not adjusted for dose rate or tumor volume. This analysis suggests that within the therapeutic range of low dose rate brachytherapy, correction of total dose according to dose rate is unnecessary. We recommend 65 Gy. Lower dose rate (0.4-0.5 Gy/hr) and closer intersource spacing (12-14 mm) should be aimed for to minimize necrosis.

Combined external irradiation and interstitial implantation for T1 and T2 epidermoid carcinomas of base of tongue: the Creteil experience (1971-1981).

Forty-eight patients with T1 or T2 epidermoid carcinomas of the base of tongue were treated at the Henri Mondor Hospital between 1971 and 1981. Forty-one patients received moderate dose 60Co external beam irradiation (mean: 48.6 Gy) to the primary tumor and regional nodes, followed by an interstitial iridium 192 implant to the primary tumor (mean: 32 Gy). This completed the treatment for the 30 node negative patients, but those with clinically positive nodes were managed by either an additional electron beam boost to the involved nodes or a neck dissection. Seven tumors were treated exclusively by implantation to the base of tongue (mean: 63 Gy). Five-year crude disease-free survival is 50% with 35% of patients dying of recurrent disease. Definitive local control for T1 lesions is 85% (11/13) and for T2 is 71% (25/35). A dose response effect was observed with local control of 79% (26/33) obtained with a combined dose greater than or equal to 75 Gy, but only 50% (4/8) for less than or equal to 70 Gy. For N0 patients definitive regional control is 97% and for N1-3 is 89%. Minor or moderate soft tissue ulceration was observed in 12 patients, including 3 cases that progressed to osteonecrosis. None required surgical intervention. No correlation exists between necrosis and tumor size or total dose.

Radiation therapy for carcinoma of the pinna using iridium 192 wires: a series of 70 patients.

From January 1970 to November 1982, 70 patients with carcinoma of the pinna were treated by interstitial irradiation. An afterloading technique with Iridium 192 wires was used. One patient recurred and had a total pinnectomy followed by 60 Gy external radiation. This patient was alive without evidence of disease at 134 months. Three patients who had tumors greater than 4 cm in size at presentation developed late necrosis which required subsequent total pinnectomy. Cosmetic results were assessed in 55 patients and were good with few late sequelae (in 78% of cases (36/46) when the tumor measured less than 4 cm, but only in 1/9 when the tumor measured more than 4 cm). We advocate interstitial Iridium 192 irradiation for treatment of pinna tumors smaller than 4 cm. None of 39 patients with squamous cell carcinoma had biopsy proven cervical lymph node metastasis at the time of diagnosis. Four patients with squamous cell carcinoma (4/39: 10%) later developed a regional nodal metastasis after treatment of the pinna. All four relapsed in the parotid region and were managed by partial parotidectomy and neck dissection followed by external irradiation. One of these four patients died from uncontrolled cervical node disease. In our opinion, when regular follow-up is dependable, it is reasonable to save treatment of the cervical nodes for those patients who relapse with involved metastatic cervical nodes.

Definitive radiation treatment for early stage carcinoma of the soft palate and uvula: the indications for iridium 192 implantation.

From 1971 to 1984 59 T1 and T2 carcinomas of the soft palate and uvula were treated definitively by irradiation at the Henri Mondor hospital. Included are ten patients previously irradiated to the oropharyngeal area for either a carcinoma of the soft palate or another malignancy. Sixteen patients were treated by external irradiation alone, 14 by Iridium 192 implantation, and 29 by a combination of the two. Two techniques of implantation were used: the guide gutter technique (33 patients) and the plastic tube technique (10 patients). Clinically negative neck nodes (51/59) either received prophylactic telecobalt therapy (39/51) or were surveilled (12/51). Clinically involved nodes (8/59) were managed either by external irradiation alone (4/8) or combined with neck dissection (4/8). Local failure was 25% (4/16) after exclusive telecobalt therapy, 18% (5/19) after combined telecobalt therapy and implantation, and 0% (0/14) after Iridium 192 implantation alone. No local failures were seen with the plastic tube technique (0/10) as compared to 15% (5/33) for guide gutters. Only two nodal failures were observed (2/59: 3%). Crude 5-year disease-free survival was 33%. Severe complications were limited to one osteonecrosis, one soft tissue necrosis, and one partial palatal incompetence. Salivary impairment was reduced when implantation was used for part or all of the treatment. We recommend 45 Gy external radiation followed by 30 Gy from Iridium 192 implantation using the plastic tube method unless there has been prior oropharyngeal irradiation, in which case we give 60 Gy from implantation alone. For clinically negative neck nodes, we recommend 45 Gy prophylactic external neck irradiation. For clinically positive lymph nodes, this should be followed by either a 25 to 30 Gy boost to the involved nodes or a neck dissection.

Interstitial radiation therapy for squamous cell carcinoma of the tonsillar region: the Creteil experience (1971-1981).

From July 1971 to December 1981, 33 selected patients with T1, T2 tumors of the tonsillar region were treated according to the following protocol: 1. Telecobalt therapy to the primary site and to neck nodes to a dose of 45 Gy. 2. Brachytherapy to the primary site to a dose of 30 Gy using iridium 192. 3. Boost dose to involved neck nodes with electrons, or radical neck dissection, whether N1, N2, or N3. The actuarial disease-free survival was 76% when all patient groups were included and 80% for the N0 patients. The local control rate was 100%. Disease control in the neck was 94% overall and 100% for the N0 group. These results favor the use of this protocol for superficial, minimally infiltrating tumors less than 4 cm in diameter, without obvious extension to the base of the tongue or retromolar trigone.

Iridium-192 curietherapy for T1 and T2 epidermoid carcinomas of the floor of mouth.

From 1970 to 1986, 117 patients with T1 (47) or T2 (70) epidermoid carcinomas of the floor of the mouth (SCC) were treated by iridium-192 implantation (192 Ir). The dose was prescribed according to the Paris System and varied over those years. Follow-up information was available on 116 patients. There were 46 T1N0, 47 T2N0, and 23 T2N1-3. Neck management varied for the 93 N0 patients consisting of surveillance (24 T1, 17 T2) or elective neck dissection (22 T1:all pN-, 30 T2: 20 pN-, 10 pN+). Cause specific survival rates were 94% for T1N0, 61.5% for T2N0, and 28% for T2N1-3 at 5 years. Primary local control was 93.5%, 74.5%, and 65%, respectively, and 98%, 79%, and 65% after salvage. Patients with gingival extension or a tumor size over 3 cm (T2b) had a local control of 50% (9/18) and 58% (15/26), respectively. Nodal control was 93.5% for Stage I, 85% for Stage II, and 48% for T2N1-3 patients. There was no difference in nodal control with regard to treatment policy for Stage I-II patients. There were few complications including three deaths: two from surgery and one from 192 Ir. Nodal status, tumor size defined as T1, T2a (less than or equal to 3 cm), T2b (greater than 3 cm), and gingival extension were the only independent prognostic factors. The management of T1N0 and T2N0 SCC by 192 Ir to a dose of 65 or 70 Gy, using the Paris System, is recommended for lesions 3 cm or less and without gingival extension.

Interstitial iridium 192 for cutaneous carcinoma of the external nose.

Several implantation techniques useful for nasal skin carcinoma have been developed at the Henri Mondor Hospital in Créteil, France and are described in detail. Iridium 192 wires, 0.3 mm in diameter, are afterloaded into either supple plastic tubes or rigid needles implanted according to the rules of the Paris system. Dosimetry is performed by computer, based on either direct measurements of active lengths and spacing, orthogonal films or a tomogram oriented in the central plane of the implant. According to a recent review by the European Curietherapy Group of 468 implants, the optimal dose is 60 Gy. The overall failure rate was 2.6%. Indications for implantation and choice of technique, based on tumor size, site, and gross morphology are discussed.

Iridium 192 implantation of T1 and T2 carcinomas of the mobile tongue.

Between 1970 and 1986, 166 patients with T1 or T2 epidermoid carcinomas of the mobile tongue were treated by iridium 192 implantation (70 T1N0, 83 T2N0, 13 T1-2 N1-3). Five-year actuarial survival was 52% for T1N0, 44% for T2aN0, and 8% for or T1-2 N1-3. Cause specific survivals were 90%, 71%, and 46%, respectively. Local control was 87% for both T1N0 and T2N0, and 69% for T1-2 N1-3. Seven of 23 failures were salvaged by surgery, increasing local control to 96% for T1 and 90% for T2. Thirty-six patients developed a minor or moderate necrosis (16% T1, 28% T2). Half of these involved bone but only five required surgical intervention. Both local control (LC) and necrosis (nec) increased with increasing dose but improvement beyond 65 Gy is minimal (less than or equal to 60 Gy: LC = 78% nec = 13%; 65 Gy: LC = 90% nec = 29%; greater than or equal to 70 Gy: LC = 94% nec = 23%). For N0 patients, neck management consisted of surveillance (n = 78), elective neck dissection followed with external irradiation for pathologically positive nodes (n = 72), or irradiation (n = 3). Clinically positive nodes (13 patients) were managed by either neck dissection followed by external irradiation if pathologically positive (n = 10) or irradiation alone (n = 3). Regional control was 79% for N0 patients, improving to 88% after surgical salvage, and was 9/13 for N1-3 patients. We recommend that T1 and T2 carcinomas of the mobile tongue be treated by iridium 192 implantation to deliver 65 Gy. Mandibular necrosis should be reduced by using an intra-oral lead-lined dental mold.

Venocclusive disease of the liver after allogeneic bone marrow transplantation in man.

One hundred and fifty-one consecutive patients underwent allogeneic bone marrow transplantation (B.M.T.) following high-dose chemotherapy and single dose total body irradiation (T.B.I.) for hematologic malignancies between September 1980 and December 1985. All patients included in this study were treated using a 60 Co beam to deliver a prescribed dose of 10 Gy to the mid-plane of the abdomen. Total body irradiation was performed the day before B.M.T. The mean instantaneous dose-rate was 3.5 cGy/min (range: 2.6 to 4.7). The real dose received was measured using thermoluminescent dosimeters (lithium borate). The difference between the doses delivered to the liver and to the mid-plane of the abdomen did not exceed 5%. The mean real dose delivered to the reference point was 10 Gy (range 8.3 to 11.7). Ninety five per cent of the patients received a dose ranging from 9.1 Gy to 10.9 Gy. High-dose cyclophosphamide was given to 126 patients with a "standard-risk" of relapse (60 mg/kg on day 5 and 4 before B.M.T.). Chemotherapy was intensified by the addition of other drugs in 25 patients with "higher-risk" of relapse. We analyzed the effect of the following pretransplant characteristics on the subsequent posttransplant development of V.O.D.: age, sex, ASAT and/or ALAT before conditioning regimen, diagnosis and status of malignant disease, history of liver disease, interval between diagnosis of hematologic malignancy and B.M.T., conditioning regimen (i.e., classical or intensified) and dose delivered to the liver during T.B.I. Seventeen patients were classified as having clinical V.O.D. giving a prevalence of 11.2%. In the first 2 months following B.M.T., death occurred respectively in 9 of 17 (53%) and 23 of 134 (17%) patients with and without clinical V.O.D. Univariate analysis showed that four characteristics were significantly related to an increased prevalence of V.O.D.: sex (11/62 females vs 6/89 males; p less than 0.05); history of liver disease (7/28 vs 10/117 patients without antecedent; p less than 0.01); ASAT and/or ALAT levels greater than 1.5 upper normal limit (11/49 vs 6/102 patients with levels less than 1.5; p less than 0.01) and intensified conditioning regimen (6/25 vs 11/126 patients with classical regimen; p less than 0.05). The conditioning regimen and history of liver disease were highly correlated to transaminases levels. Only two factors, transaminases levels and female sex, remained significantly associated with V.O.D. after multivariate analysis.

"PCL" a new automatic fast reader suitable for in vivo dosimetry.

The authors present a new automatic TLD reader specially designed for medical dosimetric applications, which allow considerable time-saving. The "PCL" reader is based on an isothermal heating kinetics and can be used with TL material of any nature and any shape (powder, microrods, pellets). Doses from 1 microGy to 10 Gy can be measured, or higher doses by interposing an optical absorber in front of the PM. The readout system is controlled by an IBM compatible personal computer. Results can be printed under the form defined by the users and then can be straightly stored in a patient sheet or an experience book. Tests performed with LiF chips TLD 100 and 700 (HARSHAW), Li2B4O7:Mn discs LiB (ALNOR), LiF powder PTL 717 (DESMARQUET) and Li2B4O7:Cu powder (CEN-FAR) are presented. They show a good reproducibility and interesting dosimetric properties.

Dosimetry of intraluminal brachytherapy.

Dose specification in intraluminal brachytherapy varies considerably in the literature. A terminology is proposed, inspired from the Paris System of interstitial brachytherapy, to define some dosimetric guidelines. The dose is specified in the central plane which is a plane perpendicular to the source and passing through its centre. The reference dose rate is calculated in this plane. The treated volume is the volume encompassed by the reference isodose. The hyperdose sleeve is the volume receiving a dose equal to or greater than twice the reference dose. A study of the dose distribution along a linear source of iridium-192 was undertaken. Results obtained, also valid for caesium-137 and cobalt-60, show that the radius of the hyperdose sleeve is relatively independent of the length of the source. It is approximately 0.6 times the distance between the source axis and the point of dose specification when the active length varies from 3 to 20 cm. Reporting not only the dose, but also the thickness of tissue covered by the reference isodose and the thickness of tissue included in the hyperdose sleeve, is recommended to assist in evaluation of the results of treatment and to facilitate the exchange of clinical information in intraluminal brachytherapy. Practical examples are given.

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)

Conservative treatment for breast cancer: long-term results (15 years).

From 1961 to 1974, 245 patients with unilateral "operable" breast cancer (25% T1, 56% T2, 19% T3) were treated with breast conservation and irradiation at the Gustave Roussy Institute (1961-1969) or at the Henri Mondor Hospital (1970-1974). The minimum follow-up is 15 years. Most patients with T greater than 3 cm underwent radiation therapy with the tumor in place, while the greater part of patients with T less than 3 cm received radiation therapy after tumorectomy. The breast and draining lymph node areas received widefield telecobalt irradiation to 45 Gy. The dose to the tumor site was boosted using iridium-192 implantation. Additional irradiation was given to the internal mammary and lower axillary nodes using an electron beam. The 15 years NED survival rate was 63%, 51% and 26% for T1, T2 and T3 tumors, respectively. The NED survival for T less than or equal to 1 cm was 86%. The local recurrence rate was 8, 12 and 19% for T1, T2 and T3 tumors, respectively. Of the patients with local recurrence, 85% underwent surgical salvage. Complications were rare. Cosmetic results were satisfactory in most patients including the T3 group. The proportion of breasts conserved among patients living NED at 15 years, was 97, 88 and 93% for T1, T2 and T3 tumors, respectively. In 1980, after almost 20 years experience using breast conserving techniques, we modified our treatment policies in close collaboration with our surgical team, hel cbye extending the indications for tumorectomy and associating routine surgical exploration of the lower axilla.

Radiotherapy in the management of mycosis fungoides: indications, results, prognosis. Twenty years experience.

PURPOSE: To determine the role of total skin electron beam therapy (TSEBT) and the prognosis of patients with mycosis fungoides. MATERIALS AND METHODS: From 1978 to 1996, 66 consecutive patients with mycosis fungoides received 30 Gy TSEBT delivered in 12 fractions over 40 days as treatment of their relapsed after topical or/and systemic therapy. All patients were staged as follows: stage A, superficial lesions covering less than 50% of the body surface; stage B, superficial lesions covering more than 50% of the body surface; Stage C. tumors involving the skin, lymph nodes and/or visceral organs. RESULTS: The median age was 50 years (ranging from 13-78 years). There were 39 males and 27 females. The minimum follow-up was 12 months (range 12-192 months). There were 24 (36%) stage A patients, 22 (33%) stage B patients, and 20 (30%) stage C patients. The overall survival at 5 years for our series was as follows: 93% for stage A; 79% for stage B, and 44% for stage C disease (P = 0.002). For the entire cohort, the complete remission rate was 65%, the progression-free survival (PFS) at 5 years and 10 years was 30 and 18% respectively. For the group A, PFS was 62% at 5 years and 46% at 10 years; for group B, PFS was 19% at 5 years. CONCLUSIONS: This study suggests that TSEBT gives good results for relapsed stage A disease. Total skin electron beam therapy combined with local fields irradiation or other local treatment (puvatherapy or topical nitrogen mustard) might further improve permanent complete response for stage B patients. The most advanced stages of mycosis fungoides are not controlled by TSEBT, but the radiation therapy offers good palliation results.

Interstitial pneumonitis and venocclusive disease of the liver after bone marrow transplantation.

One hundred and seventy patients were analysed for interstitial pneumonitis and 151 for venocclusive disease of the liver after bone marrow transplantation. We present our results with emphasis on the role of the parameters of single fraction total body irradiation.