Proton therapy analysis using the Monte Carlo method

The range and straggling data obtained from the transport of ions in matter (TRIM) computer program were used to determine the trajectories of monoenergetic 60 MeV protons in muscle tissue by using the Monte Carlo technique. The appropriate profile for the shape of a proton pencil beam in proton therapy as well as the dose deposited in the tissue were computed. The good agreements between our results as compared with the corresponding experimental values are presented here to show the reliability of our Monte Carlo method.

Primary Squamous Cell Carcinoma Arising From an Epithelium-Lined Cyst of the Lacrimal Gland

A 66-year-old man presented with a slowly enlarging, nontender left orbital mass of 2 months' duration. CT and MRI showed a left lacrimal gland mass with enhancement and internal irregularity of cystic structures. Histopathologic analysis of the biopsy specimen revealed a squamous cell carcinoma arising from an epithelium-lined cyst. The patient underwent left orbital exenteration followed by radiation treatment. No evidence of tumor recurrence was observed after a follow-up of 30 months. We believe this primary squamous cell carcinoma may have arisen either from preexisting lacrimal duct cyst (dacryops) with areas of squamous metaplasia or, less likely, from a choristomatous epithelium-lined cyst of the lacrimal gland. Although rare, this entity should be included in the differential diagnosis of cystic lesions of the lacrimal gland.

[Experimental assessment of the capacities of use of photosense. Communication 2. Photodynamic therapy for epibulbar and choroid tumors]

The study was undertaken to evaluate the efficiency of photodynamic therapy of pigmented choroid and epibulbar melanoma, by using the agent Photosense. Pigmented choroid and epibulbar melanoma were identified in 50 rabbit eyes. After intravenous injection of Photosense, 0.7 mg/kg, the tumors were irradiated at 675 nm with an argon-pumped dye laser at 150 J/cm2. Photodynamic therapy with Photosense may be effective in treating pigmented choroid and epibulbar melanomas.

Monte Carlo simulation of a protontherapy platform devoted to ocular melanoma

Patients with ocular melanoma have been treated since June 1991 at the medical cyclotron of the Centre Antoine Lacassagne (CAL). Positions and sizes of the ocular nozzle elements were initially defined based on experimental work, taking as a pattern functional existing facilities. Nowadays Monte Carlo (MC) calculation offers a tool to refine this geometry by adjusting size and place of beam modeling devices. Moreover, the MC tool is a useful way to calculate the dose and to evaluate the impact of secondary particles in the field of radiotherapy or radiation protection. Both LINAC and cyclotron producing x rays, electrons, protons, and neutrons are available in CAL, which suggests choosing MCNPX for its particle versatility. As a first step, the existing installation was input in MCNPX to check its aptitude to reproduce experimentally measured depth-dose profile, lateral profile, output-factor (OF), and absolute dose. The geometry was defined precisely and described from the last achromatic bending magnet of our proton beam line to the position of treated eyes. Relative comparisons of percentage depth-dose and lateral profiles, performed between measured data and simulations, show an agreement of the order of 2% in dose and 0.1 mm in range accuracy. These comparisons, carried out with and without beam-modifying device, yield results compatible to the required precision in ocular melanoma treatments, as long as adequate choices are made on MCNPX input decks for physics card. Absolute dose and OF issued from calculations and measurements were also compared. Results obtained for these two kinds of data, carried out in the simplified situation of an unmodulated beam, indicate that MC calculation could effectively complement measurements. These encouraging results are a large source of motivation to promote further studies, first in a new design of the ocular nozzle, and second in the analysis of the influence of beam-modifying devices attached to the final patient collimator, such as wedge or compensators, on dose values.

Design and dosimetric considerations of a modified COMS plaque: The reusable “seed-guide” insert

The Collaborative Ocular Melanoma Study (COMS) developed a standardized set of eye plaques that consist of a 0.5 mm thick bowl-like gold alloy backing with a cylindrical collimating lip. A Silastic seed carrier into which 125I seeds are loaded was designed to fit within the backing. The carrier provides a standardized seed pattern and functions to offset the seeds by 1.0 mm from the concave (front) surface of the carrier. These Silastic carriers have been found to be difficult to load, preclude flash sterilization, and are a source of dosimetric uncertainty because the effective atomic number of Silastic is significantly higher than that of water. The main dosimetric effect of the Silastic carrier is a dose-reduction (compared to homogeneous water) of approximately 10%-15% for 125I radiation. The dose reduction is expected to be even greater for 103Pd radiation. In an attempt to improve upon, yet retain as much of the familiar COMS design as possible, we have developed a thin "seed-guide" insert made of gold alloy. This new insert has cutouts which match the seed pattern of the Silastic carrier, but allows the seeds to be glued directly to the inner surface of the gold backing using either dental acrylic or a cyanoacrylate adhesive. When glued directly to the gold backing the seeds are offset a few tenths of a millimeter further away from the scleral surface compared to using the Silastic carrier. From a dosimetric perspective, the space formerly occupied by the Silastic carrier is now assumed to be water equivalent. Water equivalency is a desirable attribute for this space because it eliminates the dosimetric uncertainties related to the atomic composition of Silastic and thereby facilitates the use of either 125I and/or 103Pd seeds. The caveat is that a new source of dosimetric uncertainty would be introduced were an air bubble to become trapped in this space during or after the surgical insertion. The presence of air in this space is modeled and the dosimetric impact discussed. Another unintended consequence of water equivalency is that some fluorescent x rays emitted from the gold backing can now reach the eye. These very low energy x rays were virtually eliminated by absorption in Silastic. When loaded with 125I seeds the modified plaque appears to produce dose distributions that are almost the same as those of the original COMS plaque and the maximum dosimetric uncertainty introduced by an air bubble is about 2%. Dose distributions calculated for a modified plaque loaded with 103Pd seeds show that dose to healthy ocular structures distal to the tumor apex can be reduced compared to 125I. Clearly, it is faster and easier to glue seeds into the reusable gold seed-guide insert than it is to load the COMS-Silastic carrier.

Treatment of midfacial defects using prostheses supported by ITI dental implants

The purpose of this study was to evaluate retrospectively the use of ITI dental implants used for anchoring facial prostheses in the restorative treatment of midface defects. The authors analyzed the clinical data of 26 patients with orbital defects (n = 11), orbitonasal defects (n = 4), orbitonasomaxillary defects (n = 3), and nasal defects (n = 8). Data included age, sex, primary disease, implant position, implant length, implant failure, prosthetic attachment, radiation therapy, and peri-implant skin reactions. Follow-up was at 1, 3, 6, and 12 months and then on a yearly basis. The authors noted the status of healing and complications, if any. In total, 62 implants were placed as follows: 27 (43.5 percent) for orbital prostheses, 12 (19.4 percent) for orbitonasal prostheses, 14 (22.6 percent) for orbitonasomaxillary prostheses, and nine (14.5 percent) for nasal prostheses. Thirty-eight implants (61.3 percent) were placed in previously irradiated areas in 18 patients (69.2 percent). Mild skin reactions together with mild accumulation of sebaceous crusting around implants were recorded in 14.2 percent of the skin observations. No patient experienced severe inflammation requiring administration of systemic antibiotics or surgical revision. Implant success was 100 percent in both irradiated and nonirradiated patients. In conclusion, ITI dental implants result in a high rate of success in retaining midface prostheses and offer good stability and aesthetic satisfaction.

[Case of metastatic intraocular malignant lymphoma with neovascular glaucoma]

BACKGROUND

It is relatively rare to encounter a case of neovascular glaucoma induced by malignant lymphoma metastasized into the eyeball.

CASE

A 79-year-old woman initially visited our ophthalmology clinic with the chief complaint of blurring of vision in the left eye which was affected by neovascular glaucoma. She had a history of systemic malignant lymphoma, first diagnosed from skin biopsy and treated to complete remission 3 years previously. A metastatic brain lesion, detected 2 months before her initial visit to our clinic, was cured by radiotherapy.

FINDINGS

By ultrasound biomicroscopy (UBM) we detected abnormal thickening of the temporal half of the ciliary body of her left eye. Cytological examination of the aqueous humor revealed invasion by malignant cells of presumed lymphocyte origin. Radiation therapy to the left eye normalized the intraocular pressure in a week, followed by a reduction in the neovascularization of the iris and the thickening of the ciliary body.

CONCLUSION

This case showed that metastatic malignant lymphoma in the eye could result in neovascular glaucoma and that UBM is useful to detect and to observe lesions in the iris and ciliary body.

[Radiowave surgery for epibulbar tumor and nontumor masses]

The paper analyzes the results of removal of epibulbar tumor and nontumor masses, by using the radiowave surgical technique. The authors used two basic modes: fulguration and completely rectified and/ or completely filtered wave. Postoperative healing was aseptic and areactive. The duration of reparation depended on the working conditions, the volume of excised tissues, and the individual pattern of reparative processes. No intraoperative and postoperative complications were found. There were no cases of relapses and on-going growth during 9-12-month follow-ups. The authors have concluded that a radiowave knife may be used in surgery for epibulbar tumor and nontumor masses.

The three-dimensional scintillation dosimetry method: test for a106Ru eye plaque applicator

The need for fast, accurate and high resolution dosimetric quality assurance in radiation therapy has been outpacing the development of new and improved 2D and 3D dosimetry techniques. This paper summarizes the efforts to create a novel and potentially very fast, 3D dosimetry method based on the observation of scintillation light from an irradiated liquid scintillator volume serving simultaneously as a phantom material and as a dose detector medium. The method, named three-dimensional scintillation dosimetry (3DSD), uses visible light images of the liquid scintillator volume at multiple angles and applies a tomographic algorithm to a series of these images to reconstruct the scintillation light emission density in each voxel of the volume. It is based on the hypothesis that with careful design and data processing, one can achieve acceptable proportionality between the local light emission density and the locally absorbed dose. The method is applied to a Ru-106 eye plaque immersed in a 16.4 cm3 liquid scintillator volume and the reconstructed 3D dose map is compared along selected profiles and planes with radiochromic film and diode measurements. The comparison indicates that the 3DSD method agrees, within 25% for most points or within approximately 2 mm distance to agreement, with the relative radiochromic film and diode dose distributions in a small (approximately 4.5 mm high and approximately 12 mm diameter) volume in the unobstructed, high gradient dose region outside the edge of the plaque. For a comparison, the reproducibility of the radiochromic film results for our measurements ranges from 10 to 15% within this volume. At present, the 3DSD method is not accurate close to the edge of the plaque, and further than approximately 10 mm (<10% central axis depth dose) from the plaque surface. Improvement strategies, considered important to provide a more accurate quick check of the dose profiles in 3D for brachytherapy applicators, are discussed.

[Radiotherapy of intraocular tumors with Ruthenium-106-containing, beta-emitting ophthalmic applicators. Experiences with treatments performed between 1986 and 1999 in Hungary]

AIM

Till October 15, 2004, 312 patients were irradiated with Ruthenium-106-containing ophthalmic applicators at the Department of Ophthalmology, Medical Faculty, University of Debrecen. In this paper we report on experience gained with the irradiation of 187 patients, treated between 1986 and 1999, whose follow-up time interval was at least 5 years.

PATIENTS AND METHODS

The distribution according to diagnosis of the patients irradiated between 1986 and 1999 were: choroidal melanoma 148, retinoblastoma 15, retinal angioma 9, carcinoma metastasis 4, subretinal neovascularization 11. The instruments purchased from the German Bebig firm were sutured under surgical circumstances onto the sclera, and were removed from the eye with another operation. The applied dose calculated to the inner surface of the tumors was 100 Gy in the case of choroidal melanomas, and 50 Gy in the case of retinoblastomas.

RESULTS

From the patients irradiated because of malignant intraocular tumors 154 (95.7%) were evaluated. From the evaluated patients 148 (96.1%) are alive. Among the living patients 4 (2.7%) is suffering from distant metastasis. From the irradiated eyes 148 (96.1%) could be saved. Six eyes had to be enucleated, 1 eye because of phthisis bulbi, 2 because of hemorrhagic glaucoma, and 3 because of uncontrollable tumor growth.

DISCUSSION

With the help of radioactive isotope-containing applicators the intraocular malignant tumors can be destroyed, so that the eyes can be saved with useful vision, without risking the patients' life.

The elusive nature of primary intraocular lymphoma

A 58-year-old woman with an initial diagnosis of multiple evanescent white dot syndrome OU experienced deteriorating vision despite corticosteroid treatment. Reevaluation disclosed retinal and subretinal infiltrates and pigmentary alterations, prompting a suspicion of primary intraocular lymphoma (PIOL). Diagnostic vitrectomy yielded inconclusive cytology, but flow cytometry demonstrated small monoclonal B cells less suggestive of PIOL than of small lymphocytic lymphoma originating outside the eye or central nervous system. Brain magnetic resonance imaging, chest/abdomen/pelvis computed tomography, lumbar puncture, and laboratory studies failed to disclose lymphoma elsewhere. There was insufficient evidence to recommend radiation therapy. Vision deteriorated rapidly, prompting a diagnostic retinal biopsy and aspiration of the subretinal infiltrate, revealing unequivocal evidence of PIOL. After 40 Gy orbital x-irradiation, visual function improved dramatically. This case emphasizes the unusual ocular manifestations of PIOL and the difficulty of obtaining a definitive diagnosis by sampling vitreous, particularly after corticosteroid treatment. In such cases, subretinal aspiration or retinal biopsy may be necessary. Timely diagnosis is critical because treatment can reverse visual loss if it is not severe.

Mélanome du sac lacrymal

RESULTS

Mean stage (NOSPECS classification) at time of surgery was 4.5 (range 2-6). Mean stage postoperatively was 2.4 (range 0-5). Comparison of the mean stages showed significant improvement of ocular protrusion: 1.55 (range 1-2) postoperatively versus 2.4 preoperatively. Among the patients with optic neuropathy (stage 6, n=12), 83% (10/12) normalized PEV with normal or clear improvement in visual acuity three months postop. Diplopy remained unchanged in 45% (5/11) and improved in 45% (5/11), worsening in one patient. Clinical regression of the exophthalmia, irrespective of the intensity initially, was noted in 93% of patients at six months postop. All patient had overall improvement in the position of the eyelids at rest..

A simple calibration method for 106Ru–106Rh eye applicators

Ru-Rh eye applicators are used for the radiotherapy of eye malignancies such as melanomas. We present a method of dosimetry of these beta particle emitting applicators. Method is based on a Plexiglas phantom (constructed for this purpose) containing spherical shells and very small, 1x1x1mm3 thermoluminescent dosimeters (TLD) as dosimeters. We determined 3-D depth doses and interpolated depth dose functions. Surface dose rate inhomogeneities and the consequences were considered and discussed. A possible influence of photon component of the emission on the results was analysed. The method has overall combined uncertainty + or -6% which is comparable, and slightly better, than other recent dosimetric methods.

A case of primary ductal adenocarcinoma of the lacrimal gland: histopathological and immunohistochemical study

We encountered primary ductal adenocarcinoma of the lacrimal gland in a 67-year-old Japanese man. To the best of our knowledge, only three cases of primary ductal adenocarcinoma of the lacrimal gland have been reported in the literature. The patient was admitted because of visual disturbance, and a mass measuring about 3 cm in diameter was revealed in the right orbit. The mass was resected, and primary ductal adenocarcinoma of the lacrimal gland was diagnosed histopathologically. He died from recurrence at the primary site and metastasis to the brain, lungs, liver, common bile duct, and pancreas 2 years and 10 months after surgery although adjunctive orbital radiotherapy was given. Immunohistochemically, the characteristics of cancer cells were similar to those of salivary duct carcinoma, namely positivity for cytokeratin (CK) 7, 10, 17, 18, 19, and 34betaE12, and negativity for CK20. It was not clear whether the ductal adenocarcinoma originated from the ductal or acinar epithelium of the lacrimal gland, because the immunohistochemical features of both epithelia were identical.

The Monte Carlo SRNA-VOX code for 3D proton dose distribution in voxelized geometry using CT data

This paper describes the application of the SRNA Monte Carlo package for proton transport simulations in complex geometry and different material compositions. The SRNA package was developed for 3D dose distribution calculation in proton therapy and dosimetry and it was based on the theory of multiple scattering. The decay of proton induced compound nuclei was simulated by the Russian MSDM model and our own using ICRU 63 data. The developed package consists of two codes: the SRNA-2KG, which simulates proton transport in combinatorial geometry and the SRNA-VOX, which uses the voxelized geometry using the CT data and conversion of the Hounsfield's data to tissue elemental composition. Transition probabilities for both codes are prepared by the SRNADAT code. The simulation of the proton beam characterization by multi-layer Faraday cup, spatial distribution of positron emitters obtained by the SRNA-2KG code and intercomparison of computational codes in radiation dosimetry, indicate immediate application of the Monte Carlo techniques in clinical practice. In this paper, we briefly present the physical model implemented in the SRNA package, the ISTAR proton dose planning software, as well as the results of the numerical experiments with proton beams to obtain 3D dose distribution in the eye and breast tumour.

Treatment-induced leukoencephalopathy in primary CNS lymphoma: a clinical and autopsy study

BACKGROUND

Treatment-related leukoencephalopathy is the leading toxicity after successful treatment of primary CNS lymphoma (PCNSL). Its mechanism is poorly understood and there are no autopsy data available on such patients.

METHODS

From a database of immunocompetent patients with PCNSL diagnosed between 1985 and 2001, the authors identified five autopsied patients who died of leukoencephalopathy. The authors reviewed their clinical records, MRI, and autopsy findings.

RESULTS

The median age was 74 years (range 41 to 79) at PCNSL diagnosis. Symptoms of neurotoxicity developed a median of 1 month after treatment completion, and median survival was 30 months (range 22 to 68 months) after neurotoxicity onset. All had white matter hyperintensity on T2-weighted MRI, and two developed enhancing lesions 5 and 14 months following completion of treatment. At autopsy no PCNSL was identified. Myelin and axonal loss, gliosis, pallor, spongiosis, and rarefaction of the white matter were found in all; two patients had tissue necrosis that correlated with the enhancement on MRI, and one had fibrinoid necrosis of vessels. Four of the five patients had atherosclerosis of large cerebral vessels in the circle of Willis and all had small vessel disease; two had recent strokes at autopsy.

CONCLUSIONS

Treatment-induced leukoencephalopathy is not a late delayed consequence of neurotoxic treatment but can be seen very early in some patients. Vascular disease may be a component of this white matter injury.

A new human eye model for ophthalmic brachytherapy dosimetry

The present work proposes a new mathematical eye model for ophthalmic brachytherapy dosimetry. This new model includes detailed description of internal structures that were not treated in previous works, allowing dose determination in different regions of the eye for a more adequate clinical analysis. Dose calculations were determined with the MCNP-4C Monte Carlo particle transport code running n parallel environment using PVM. The Amersham CKA4 ophthalmic applicator has been chosen and the depth dose distribution has been determined and compared to those provide by the manufacturer. The results have shown excellent agreement. Besides, absorbed dose values due to both 125I seeds and 60Co plaques were obtained for each one of the different structures which compose the eye model and can give relevant information in eventual clinical analyses.

Virtual commissioning of a treatment planning system for proton therapy of ocular cancers

The virtual commissioning of a treatment planning system (TPS) for ocular proton beam therapy was performed using Monte Carlo (MC) simulations and a model of a double-scattering ocular treatment nozzle. The simulations produced both the input data required by the TPS and the dose distributions to validate the analytical predictions from the TPS. An MC simulation of a typical ocular melanoma treatment was compared with the TPS predictions, revealing generally good agreement in the absorbed dose distribution. However, in the depth-dose profiles, differences >5% existed in the proximal region of all validation cases considered. Comparison of the radiation coverage at or above the 90% dose level, showed that MC calculated coverage was 82% and 68% of the coverage calculated by the TPS in two planes intersecting the tumour.

Treatment of medium-sized juxtapapillary melanoma with external Co-60 photon therapy

Twenty-six patients with medium-sized juxtapapillary choroidal melanomas were irradiated using D-shaped Co-60 beams. The overall 5-year actuarial survival was 86% with a trend towards better 5-year local control with 70 vs. 60 Gy (100 vs. 75%). Of patients with pre-treatment > or =20/200 visual acuity, 37% had functional vision at 5 years.

Metastatic lung cancer: presenting with ocular symptoms

A 48 year-old man, without any systemic disease, was admitted to our hospital with a complaint of decreased visual acuity and pain in his left eye. The orbital magnetic resonance imaging revealed metastatic lesions and further evaluations disclosed a primary lung cancer.

106Ru/106Rh plaque and proton radiotherapy for ocular melanoma: a comparative dosimetric study

The objective of this study was to perform comparative dosimetric studies of both 106Ru/106Rh plaque brachytherapy and external beam proton therapy proposed for ocular treatments at the University of Texas M. D. Anderson Cancer Center, Houston, TX, USA. These modalities were also compared with traditional 125I plaque brachytherapy. Using a standardised eye model with a representative ocular melanoma tumour, the relative dose distributions within the tumour and surrounding tissue were calculated using the Monte Carlo code MCNPX. Published absorbed dose distributions benchmarked the Monte Carlo models. Results indicate that the proton beam provided superior dose uniformity within the tumour volume, whereas the dose distribution from 106Ru/106Rh was more heterogeneous. Relative to 125I COMS plaque, both 106Ru/106Rh and protons have shown more confined dose distributions to the tumour volume in this situation, thus sparing other critical ocular structures. For protons, it has been shown that only doses lower than the maximum dose are delivered outside the tumour volume. Depending on the clinical situation, this may aid in the sparing of critical structures located in the sclera and optic disc boundary. The Monte Carlo model's statistical uncertainties of the mean dose estimates for the 106Ru/106Rh plaque and proton beam were 3 and 2.5%, respectively.

Radiotherapie von Augen- und Orbitatumoren

Malignant diseases of the orbit are multifaceted and require in the majority of the cases an interdisciplinary treatment. Advances in radiotherapy, surgery and chemotherapy make a high cure rate possible, especially in children's tumors. In adults these tumors reach a tumor control rate of nearly 90 %, even with preservation of the eye in most of the cases. There are only two curative therapy options for tumors in this region: radiotherapy and surgery. The therapy for tumors of the eye and the orbit require the total spectrum of the radiotherapeutic techniques depending on the tumor entity, its spread and localization. In a prevailing number of malignant tumors (tumors of the eyelids, tear glands, orbit, metastases) the application of the radiotherapy as an external, fractionated radiotherapy is standard practice, if necessary in combination with operation and/or chemotherapy. Particularly in the therapy for ocular tumors brachytherapy with radionuclides (e. g., ruthenium) is possible and in a few centers world-wide proton therapy is available. As an alternative procedure in special modalities, stereotactic radiotherapy may be considered. Altogether the new radiotherapy techniques permit a dose increase in the tumor region and/or a reduction of the doses to healthy tissues and lead so to a better local tumor control rate and a decrease in acute and chronic side effects.

Effects of treatment with and without adjuvant radiation therapy on recurrence of ocular and adnexal squamous cell carcinoma in horses: 157 cases (1985-2002)

OBJECTIVE

To determine the effects of treatment with and without adjuvant radiation therapy on recurrence of ocular and adnexal squamous cell carcinoma (SCC) at specific anatomic locations in horses.

DESIGN

Retrospective study.

ANIMALS

91 horses.

PROCEDURES

Medical records of horses with histologically confirmed ocular and adnexal SCC evaluated from 1985 to 2002 were reviewed. Sex, breed, age, type of treatment, location, and recurrence of SCC were recorded. Two treatment groups determined by recurrence of SCCs treated with and without adjuvant radiation therapy were established.

RESULTS

The anatomic site with the highest recurrence rate was the limbus (junction of the cornea and sclera) or bulbar conjunctiva (477%), independent of treatment group. There was a significant difference in recurrence rates of ocular and adnexal SCCs between the 2 treatment groups, independent of anatomic location. Recurrence rates of SCCs treated with and without adjuvant radiation therapy were 11.9% and 44.1%, respectively. Recurrence rates for SCCs of the eyelid, limbus or bulbar conjunctiva, and cornea treated with adjuvant radiation therapy were significantly different from those for SCCs treated without adjuvant radiation therapy. The most frequently represented anatomic site for ocular and adnexal SCCs was the eyelid (28.7%). Coat color, breed, and the interaction of age and breed had a significant effect on tumor recurrence regardless of treatment type and anatomic location.

CONCLUSIONS AND CLINICAL RELEVANCE

Results indicated that ocular and adnexal SCCs treated with adjuvant radiation therapy had a significantly lower recurrence rate, compared with SCCs treated without adjuvant radiation therapy, independent of anatomic location.

Systemic melanoma metastatic to the retina and vitreous

PURPOSE

Report of a case of retinal and vitreous metastases of a systemic melanoma, possibly arising in the lung, that responded favourably to radiotherapy.

CASE REPORT

Retinal and vitreous metastases were demonstrated in a 57-year-old woman during routine follow-up after surgical resection of a melanoma presumed to be a primary pulmonary melanoma. After a 7-week observation period, which confirmed the progressive nature of the intra-ocular lesions, the patient was treated by external beam radiotherapy at a dose of 35 Gy delivered in 14 fractions of 2.5 Gy. Complete disappearance of the vitreous invasion and progressive elimination of the retinal invasion were observed over a period of 9 months. Final visual function was 20/25. REVIEW OF PUBLISHED CASES: A review of the literature identified 28 cases of melanoma with metastases to the retina and vitreous. In almost all of these cases, the primary tumour was a cutaneous melanoma and the mean patient survival following the diagnosis of intra-ocular metastases was 22 months. Retinal metastases, as in the case reported here, present a vascular tropism and tend to develop around veins. These metastases are generally unilateral and may be either solitary or multiple. Tumour invasion of the vitreous occurred by means of isolated cells forming a suspension of aggregates or spherules. Vitreous haemorrhage and irreducible neovascular glaucoma leading to functional impairment, which requires enucleation, were both the most frequent and the most serious complications of these metastases. Treatment is always palliative and is effective in cases with limited retinal and vitreous invasion, as in the case reported here.

CONCLUSIONS

Metastatic melanoma in the retina and vitreous is a rare entity and can lead to functional impairment and enucleation because of neovascular glaucoma. As treatment is only effective in cases with limited invasion, systematic screening is recommended in all patients with a metastatic cutaneous melanoma presenting with suggestive ocular symptoms.

Dosimetric study of the 15mm ROPES eye plaque

The main aim of this paper is to make a study of dose-rate distributions obtained around the 15 mm, radiation oncology physics and engineering services, Australia (ROPES) eye plaque loaded with 125I model 6711 radioactive seeds. In this study, we have carried out a comparison of the dose-rate distributions obtained by the algorithm used by the Plaque Simulator (PS) (BEBIG GmbH, Berlin, Germany) treatment planning system with those obtained by means of the Monte Carlo method for the ROPES eye plaque. A simple method to obtain the dose-rate distributions in a treatment planning system via the superposition of the dose-rate distributions of a seed placed in the eye plaque has been developed. The method uses eye plaque located in a simplified geometry of the head anatomy and distributions obtained by means of the Monte Carlo code GEANT4. The favorable results obtained in the development of this method suggest that it could be implemented on a treatment planning system to improve dose-rate calculations. We have also found that the dose-rate falls sharply along the eye and that outside the eye the dose-rate is very low. Furthermore, the lack of backscatter photons from the air located outside the eye-head phantom produces a dose reduction negligible for distances from the eye-plaque r<1 cm but reaches up to 20% near the air-eye interface. Results showed that the treatment planning system lacks accuracy around the border of the eye (in the sclera and the surrounding area) due to the simplicity of the algorithm used. The BEBIG treatment planning system uses a global attenuation factor that takes into account the effect of the eye plaque seed carrier and the lack of backscatter photons caused by the metallic cover, which in the case of a ROPES eye plaque has a default value of T= 1 (no correction). In the present study, a global attenuation factor T=0.96 and an air-interface correction factor which improve on treatment planning system calculations were obtained.

Benetzungsst�rungen nach Netzhautchirurgie und okul�rer Tumortherapie

BACKGROUND

Dry eye symptoms can often be observed following vitreo-retinal operations, however, little is known about the frequency and severity of these postoperative problems.

METHODS

Examination of 140 patients following vitreo-retinal surgery ( n=31), brachytherapy ( n=76), proton beam radiation ( n=33) and controls ( n=54) using a questionnaire together with a clinical examination of the anterior segment, tear break-up time and a Schirmer test.

RESULTS

Of the treated patients 63% complained of dry eye symptoms versus 40% of the controls ( p=0.004). The tear break-up time was decreased in treated patients ( p<0.001, medians: 15 vs. 20 s). No significant difference was seen on the Schirmer test ( p=0.825; medians: 12 vs. 12 mm).

CONCLUSIONS

Dry eye symptoms are a common postoperative complication following vitreo-retinal surgery and ocular tumour therapy.

Plaque radiotherapy for choroidal and ciliochoroidal melanomas with limited nodular extrascleral extension

BACKGROUND

Currently available clinical information regarding management of posterior uveal melanomas complicated by nodular extrascleral extension is inadequate to determine the role, if any, for plaque radiotherapy in such patients.

METHODS

The authors performed a retrospective descriptive study of eight patients with a choroidal or ciliochoroidal melanoma complicated by nodular extrascleral extension who were treated by surgical excision of the extrascleral nodule followed immediately by plaque radiotherapy of the intraocular tumour. The calculated volume of the extrascleral nodule was greater than 1 mm3 but less than 1000 mm3 in all cases, and the intraocular tumour was deemed treatable by plaque radiotherapy in all patients.

RESULTS

Four of the eight patients died during available follow-up, three from metastatic melanoma and one from a second cancer. The median length of follow-up for the four surviving patients was 10.1 years. The actuarial 5-year and 10-year all-cause death rates were 37.5% and 53.1% respectively. One of the eight patients experienced local intraocular tumour relapse following plaque therapy and underwent secondary enucleation. None of the patients experienced orbital tumour recurrence or underwent secondary orbital exenteration.

INTERPRETATION

Our results coupled with previously published results from another centre suggest that plaque radiotherapy may be an effective local treatment for selected patients with choroidal or ciliochoroidal melanoma complicated by nodular extrascleral extension. The fact that none of the patients in this series or in the previously reported series experienced orbital recurrence following plaque radiotherapy or required secondary orbital exenteration suggests that plaque therapy may be better than enucleation alone in terms of these end points. These results should not be extrapolated, of course, to patients with massive extrascleral tumour extension or a choroidal or ciliochoroidal melanoma too large for plaque radiotherapy.

Modelling survival after treatment of intraocular melanoma using artificial neural networks and Bayes theorem

This paper describes the development of an artificial intelligence (AI) system for survival prediction from intraocular melanoma. The system used artificial neural networks (ANNs) with five input parameters: coronal and sagittal tumour location, anterior tumour margin, largest basal tumour diameter and the cell type. After excluding records with missing data, 2331 patients were included in the study. These were split randomly into training and test sets. Date censorship was applied to the records to deal with patients who were lost to follow-up and patients who died from general causes. Bayes theorem was then applied to the ANN output to construct survival probability curves. A validation set with 34 patients unseen to both training and test sets was used to compare the AI system with Cox's regression (CR) and Kaplan-Meier (KM) analyses. Results showed large differences in the mean 5 year survival probability figures when the number of records with matching characteristics was small. However, as the number of matches increased to > 100 the system tended to agree with CR and KM. The validation set was also used to compare the system with a clinical expert in predicting time to metastatic death. The rms error was 3.7 years for the system and 4.3 years for the clinical expert for 15 years survival. For < 10 years survival, these figures were 2.7 and 4.2, respectively. We concluded that the AI system can match if not better the clinical expert's prediction. There were significant differences with CR and KM analyses when the number of records was small, but it was not known which model is more accurate.

Ocular presentation of primary central nervous system lymphoma: diagnosis and treatment

Primary ocular lymphoma (POL), a lymphoma of the globe, is a restricted form of primary central nervous system lymphoma (PCNSL) that often progresses to the brain and meninges; frequently it is misdiagnosed until central nervous system (CNS) lymphoma develops. The optimal treatment has not yet been identified. We retrospectively reviewed the course and the treatment of POL in 31 patients. Seventeen patients were treated for isolated POL (group A) and 14 were treated only after CNS disease was diagnosed (group B). The treatment in both groups consisted of systemic chemotherapy, chemotherapy plus radiotherapy (RT) or RT alone. In group A, nine patients (53%) developed CNS progression and five (29%) had ocular recurrence. In group B, seven (50%) had CNS progression and three (21%) ocular relapse. To control for diagnostic lead time, median survival was calculated from initial ocular symptoms and was 60 months in group A and 35 months in group B (P < 0.05). Ocular lymphoma responds to a variety of therapies but treatment with chemotherapy and/or ocular radiotherapy (ORT) failed to prevent CNS progression. Patients whose ocular disease was identified and treated before CNS progression had a significantly improved survival.

Primary sebaceous carcinoma of the lacrimal gland treated by carbon ion radiotherapy

Sebaceous carcinoma is a rare primary neoplasm of the lacrimal gland and, to the best of our knowledge, only six cases have been reported previously. Sebaceous carcinoma of the orbit more commonly occurs as secondary invasion from the eyelid, but may occur by way of metastatic spread from elsewhere in the body. We describe a patient who presented with a rapidly growing neoplasm of the lacrimal gland which, histologically, was a sebaceous carcinoma. The eyelid was entirely normal on examination. In this patient we found a single tumor cell line within the normal lacrimal gland. In this article we describe the diagnosis and treatment with carbon ion radiotherapy of primary sebaceous carcinoma of the lacrimal gland, a condition not previously reported in Japan.

Bone marrow transplantation for therapy-related acute myeloid leukemia in congenital retinoblastoma associated with 13q deletion syndrome

Children with constitutional deletion of the long arm of chromosome 13 are at risk for retinoblastoma (RB) due to loss of the RB tumor suppressor gene. The prognosis is poor since the tumors are often bilateral, aggressive, and recurrent and the patients often harbor other congenital abnormalities. One further complication is that of therapy-related malignancies later in life. We report a case of allogeneic stem cell transplantation for therapy-related acute myeloid leukemia in an 8-year-old girl after multimodality treatment for refractory bilateral relapsing RB, with excellent outcome in both the ophthalmic and marrow disease.

[Five years of proton therapy of eye neoplasms at the Hahn-Meitner Institute, Berlin]

Eye tumors (choroidal melanomas, iris melanomas, and choroidal hemangiomas) are being treated with 68 MeV protons since 1998 at the Ion Beam Laboratory of the Hahn-Meitner Institute of Berlin (Germany's first proton therapy center), in cooperation with the Charité University Hospital in Berlin, Campus Benjamin Franklin. The proton beam, generated via a combination of Van de Graaff accelerator and cyclotron, is prepared by passive shaping for conformal tumor irradiation. A digital X-ray verification of the tumor location with the patient in sitting position limits the position uncertainties to a maximum of 0.3 mm. The treatment planning is performed using the program EYEPLAN. OCTOPUS, a CT-based planning program developed in cooperation with the German Cancer Research Center of Heidelberg, is under pre-clinical testing. Thus far, more than 400 patients have been irradiated. The first results are comparable to those obtained in other proton therapy centers. At the end of 2002, the University Hospital of Essen has also become a cooperation partner of the Hahn-Meitner Institute.

On the Actual State of Industrial Quality Assurance Procedures with Regard to 106Ru Ophthalmic Plaques

BACKGROUND

In radiotherapy of intraocular tumors, e. g., in the case of malign choroid melanomas, episcleral brachytherapy with (106)Ru ophthalmic plaques has proven to be successful. In a study, the authors reported on the discovery of the following shortcomings in industrial quality assurance, which are relevant to therapy, during the course of an internal clinical acceptance test of (106)Ru ophthalmic plaques, manufactured by the company Bebig from Berlin, Germany. This consisted of inconsistent dose rate specifications in the manufacturer's certificate, covering a range of 111% and with the risk of leakage of the plaques. Bebig was called upon to adapt state-of-the-art production methods with regard to (106)Ru ophthalmic plaques.

MATERIAL AND METHODS

In the meantime, Bebig has modernized production of (106)Ru ophthalmic plaques and adopted all the quality assurance procedures proposed by the authors. Moreover, the requested traceability of the calibration of activity and dose rate of the (106)Ru ophthalmic plaques to standards of the federal authorities in charge of measurement procedures has been implemented.

RESULTS

In the year 2002, Bebig updated, among other things, the ASMW (GDR) calibration of the dose rate of the (106)Ru ophthalmic plaques from the years 1987-1989 by a calibration of the NIST (USA). The current NIST calibration, together with the new equipment for the measurement of the depth dose curves, led to the consequence that the new NIST 2001 dose rate values show, in the mean, a deviation of 0.75 times (plaque type CCC) up to 2.06 times (plaque types CCX, CCY, and CCZ) compared to the dose rate values that had been indicated so far in Bebig's certificate, based on the ASMW 1987 calibration. For the 95% confidence interval, Bebig estimated the measurement uncertainty to be +/- 25%. If one takes into consideration the minimal and maximal values in such 95% confidence intervals, it follows that the new NIST 2001 dose rate values deviate between 0.56 times (plaque type CCC) and 2.58 times (plaque types CCX, CCY, and CCZ) from the Bebig certificate (ASMW calibration 1987). As regards leakage, no objections arose in the case of the (106)Ru ophthalmic plaques produced according to the new quality standards.

CONCLUSION

Legislation has to make sure that the use of radioactive material on humans be, among other things, permitted as a matter of principle only, if the dose rate calibration can be traced to standards of a federal authority of measurement procedures. Furthermore, special leakage tests for radiation sources which come into direct contact with body fluids should be established. A historical retrospect reveals that the greatest changes have taken place in the indication of the dose rates of (125)I sources. Since the beginning of the use of (125)I sources in brachytherapy in the late 1960s, the dose rate indications, so far, have had to be reduced in small steps over a period of about 35 years by nearly a factor of 2. As regards the (106)Ru ophthalmic plaques, the NIST 2001 calibration has resulted in a comparable reduction of the dose rate indications of up to a factor of 2 within the period of about several months. Thus, in the previous history of radiotherapy this case must be regarded as unique, because for the first time ever, an urgently needed recalibration has been protracted for such an unduly long period of time.

The design and the dosimetry of bi-nuclide radioactive ophthalmic applicators

A novel type of applicator for the treatment of intra-ocular tumors has been developed, based on the two radionuclides 106Ru/106Rh and 125I. The dose distribution of this ophthalmic plaque combines advantageous features of both radionuclides and can be optimally adapted to a tumor thickness in the range 6.5-9 mm, a size which is beyond the dosimetric limitations of the 106Ru/106Rh plaque therapy. Compared with 125I plaques a bi-nuclide plaque allows to maintain the tumor dosage while the dose in the irradiated volume outside of the target volume is significantly reduced. Consequently, radiosensitive structures within the eye can be spared more effectively. Dedicated methods have been developed for the dosimetry of this plaque. These methods are based on our own extensive dosimetric investigations with plastic scintillators. The precondition was the availability, developed in recent years, of a more accurate determination of the absolute dose rate to water of beta- and low energy emitters.

Intensity-modulated Radiation Therapy for Children with Intraocular Retinoblastoma:Potential Sparing of the Bony Orbit

AIMS

We have evaluated the potential for intensity-modulated radiation therapy (IMRT) to reduce dose to surrounding normal tissues in children with retinoblastoma confined to the globe of the eye.

MATERIALS AND METHODS

Treatment planning computed tomography (CT) scans from five children were used for comparison of four radiotherapy techniques to treat the eye. IMRT, conformal, anterior-lateral photon and en face electron plans were generated using the Corvus (NOMOS) and PLUNC treatment planning systems. Doses to surrounding critical structures were compared after normalisation of target coverage.

RESULTS

The IMRT treatment technique allowed the greatest sparing of the surrounding bony orbit, with an average of 60% of the ipsilateral bony orbit treated above 20 Gy and 48% treated above 24 Gy when 45 Gy is prescribed to the globe. IMRT techniques reduced dose to the surrounding bony orbit by more than one-third compared with anterior-lateral photon and electron techniques, and by 23% compared with conformal techniques. The application of IMRT also reduced dose to other surrounding normal tissues, including the temporal lobe and contralateral orbit.

CONCLUSION

IMRT shows potential for protecting normal tissues in patients requiring external beam radiation therapy for retinoblastoma.

Feature extraction and supervised classification of MR images to support proton radiation therapy of eye tumors

Proton therapy has the potential for high-precision radiotherapy of retinal tumors. However, the standardized eye models currently used do not fully account for the patient's individual anatomy. To better exploit the data provided by MR images, a model-based approach was used based on a database of eye models. A face recognition algorithm was advanced to define similarity criteria between the reference image and the actual image. After building a high-dimensional feature vector and using a training data set, the reference model was selected by using the minimum Mahalanobis distance between the image to be classified and the reference images.

Microcystic Adnexal Carcinoma of the Eyebrow

PURPOSE

To describe a case of the largest reported microcystic adnexal carcinoma of the eyebrow in an 89-year-old woman and to review the literature regarding the periorbital occurrence of this tumor.

METHODS

Case report and literature review.

RESULTS

This case was treated with primary excision and radiotherapy, with no clinical signs of recurrence in the past 6 months.

CONCLUSIONS

Microcystic adnexal carcinoma is a rare tumor; however, because of its aggressive local infiltration, ophthalmologists should consider this diagnosis and complete surgical excision. Long-term data are needed to establish outcomes from the different treatment options.

Lymphoproliferative L�sionen der okul�ren Adnexe

The ocular adnexal lymphomas represent the malignant end of the spectrum of lymphoproliferative lesions which occur in the conjunctiva, eyelids, lacrimal gland and orbit. The new "W.H.O. Classification of Tumours of Haemopoietic and Lymphoid Tissues" is the most suitable for subdividing the ocular adnexal lymphomas, whereby the extranodal marginal zone B-cell lymphoma (EMZL) represents the most common lymphoma subtype. Management of patients with ocular adnexal lymphomas includes a systemic medical examination to establish the clinical stage of the disease. Most patients have stage IE disease and current recommended therapy for this is radiotherapy, while disseminated disease is treated with chemotherapy. Despite usually demonstrating an indolent course, EMZLs are renowned for recurrence in extranodal sites, including other ocular adnexal sites. Furthermore, Blastic transformation of EMZL with a corresponding aggressive clinical course has been described. Long-term follow-up with half-yearly examinations are therefore recommended. Major prognostic criteria for the ocular adnexal lymphomas include the age of the patient, anatomical location of the tumour, stage of the disease at first presentation, serum lactate dehydrogenase level at the time of diagnosis, lymphoma subtype as determined using W.H.O. lymphoma classification and the tumour cell growth rate. The clinical symptoms and histopathological findings of the differential diagnosis of lymphoproliferative lesions of the ocular adnexa are discussed.

Clinical study on the metastasis to the eyes from breast cancer

In our hospital, 24 patients who underwent surgery for breast cancer during 1980 to 2001 were diagnosed with metastasis to the eye. Metastasis to the choroid was found most frequently, making the choroid the most common site of metastasis. A few patients had metastasis to the orbit. Decreased visual acuity and tunnel vision were frequently found in patients who had metastasis to the choroid, and ocular floaters and blurred vision were also found in a few patients. Patients with metastasis to the orbit showed diplopia caused by ocular dyskinesia and eyelid swelling. The mean postoperative period until the diagnosis with metastasis to the eye was 3 years and 2 months, with most cases diagnosed between 20 and 40 months postoperatively, a relatively long period. We performed radiotherapy in 21 of the 24 patients, and more than half of the patients showed improvement. The mean survival period after diagnosis with metastasis to the eye was 10 months, and some of them already had recurrence to other organs such as the bones or lungs. Examination with consideration of metastasis to the eyes is required to improve the quality of life of cancer patients,.

BANG®-Polymergeldosimetrie in der Protonentherapie von Augentumoren

The use of polymer gel makes it possible to measure three-dimensional dose distributions of ionizing radiation. Phantoms with BANG-1 and BANG-3 gel were irradiated using a 68 MeV proton beam at the eye tumour therapy beam line of the Hahn Meitner Institute in Berlin. Up to twelve treatment fields could be applied to one gel phantom. The investigations consisted of mono-energetic Bragg curves, spread-out Bragg curves of circular fields (diameter 20 mm), and spread-out Bragg curves of patient fields. Magnetic resonance imaging was used to obtain the gel dose distributions. The results were compared to measurements of a water-phantom ionization chamber. The BANG polymer gels showed a significant quenching of Bragg peaks compared to ionization chamber measurements. The BANG-3 gel was found to be unsuitable for further investigations with 68 MeV protons. The use of BANG-1 allowed the verification of wedge slopes and irregular field forms. On the basis of our experience, polymer gels are well suited for quality assurance in proton therapy in principle.

Ocular Metastases from Breast Carcinoma

Intraocular metastases are the most common malignancy of the eye, and the primary cause is breast cancer. This is a retrospective analysis, which reports the clinical experience of eye metastases in 16 patients during the period of January, 1991, to December, 2002, who attended a tertiary referral center in Mexico City. Mean age at diagnosis was 40 yr (range 24-58). Most of patients were initially in clinical stage IIB-IV. Median time from breast cancer diagnosis to development of ocular metastases was 22.5 mo and from metastatic disease to ocular metastases was 10 mo. Ocular symptoms were decrease of visual acuity, ocular pain, nonspecific symptoms, proptosis, and palpebral edema. Three patients had bilateral ocular metastases. Fourteen patients were treated with radiation, and clinical response was documented in 4/15 eyes; ocular pain responded in three patients with this symptom. No ocular enucleations were performed. One patient developed glaucoma. No other major toxicities were documented. Median survival time was 26 mo and 25% of our patients were alive at a maximum follow-up of 90 mo. This entity requires early recognition in order to preserve the visual function and quality of life of patients with breast cancer, since their prognosis has improved in recent years.

[The organ-saving treatment of intraocular tumors (development trends)]

A trend towards an increase of malignant tumors observed during the recent 30-40 years, an unsatisfactory efficiency of enucleation as of a method applicable to treating such tumors and the designing of a modern technical basis stimulated a new trend in ophthalmooncology, i.e. organ-saving treatment. Outlined in the paper is an analysis of achievements of modern radiation treatment techniques and of local surgical extraction of tumors suggested both by Russian and foreign researchers; the methods are shown to be promising for future development.

Radiation dose profile in 125I brachytherapy: an 8-year review

The use of episcleral plaques containing radioactive 125I seeds for brachytherapy treatment of selected retinoblastoma cases of patients is being done in Riyadh, Saudi Arabia since 1994. There are about three to four patients per year. A total of 31 patients were treated with a tumour dose in the range of 40-60 Gy using 8 seeds of 125I each from 1994 to 2002. This study determines the trend of occupational doses received by surgeons, anaesthesiologists and nurses and the dose rate profile around the eyes. Only 3% of the 275 persons monitored for Hp(10) have measurable doses with a weighted average of 4 microSv and 7% of the 175 persons monitored for Hp(0.07) have measurable doses with a weighted average of 0.3 mSv. The dose rate is maximum (110 microSv h(-1)) at the point of contact with the eye plaque and reduces to approximately 40% on the side of the other eye.

Squamous cell carcinoma of the lacrimal sac: a case report

Lacrimal sac tumors are rare tumors of the periorbital region. The authors report a case of squamous cell carcinoma of the lacrimal sac in a 47-year-old Thai man. The patient presented with epiphora and a palpable mass in the medial canthal area. The diagnosis was confirmed by the pathological studies. Radical surgery and radiation therapy were given. Early detection and long-term follow-up are necessary.

Ocular adnexal lymphoma: Clinical behavior of distinct World Health Organization classification subtypes

PURPOSE

To evaluate the clinical behavior and treatment outcome of ocular adnexal lymphomas classified by the World Health Organization system, with emphasis on marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT).

MATERIALS AND METHODS

The clinicopathologic materials from 98 consecutive patients treated for ocular adnexal lymphoma were reviewed. Fourteen patients had prior lymphoma and 84 patients had primary disease (75% Stage I, 6% Stage III, and 19% Stage IV). Radiation (photons/electrons) was administered to 102 eyes to a median dose of 30.6 Gy. The mean follow-up was 82 months.

RESULTS

The most common subtypes among the primary patients were MALT (57%) and follicular (18%) lymphoma. The 5-year actuarial local control rate in 102 irradiated eyes was 98%. Among the low-grade lymphomas, the 5-year local control rate correlated with the radiation dose in the MALT lymphoma subgroup (n = 53): 81% for <30 Gy and 100% for > or =30 Gy (p <0.01). For the non-MALT low-grade lymphomas such as follicular lymphoma (n = 30), the local control rate was 100% regardless of dose. For 39 Stage I MALT lymphoma patients treated with radiation alone, the distant relapse-free survival rate was 75% at 5 years and 45% at 10 years. Distant relapses were generally isolated and successfully salvaged by local therapy. The overall survival for this subgroup was 81% at 10 years, with no deaths from lymphoma.

CONCLUSIONS

Dose-response data suggest that the optimal radiation dose for MALT lymphoma of the ocular adnexa is 30.6-32.4 Gy in 1.8-Gy fractions and follicular lymphoma is adequately controlled with doses in the mid-20 Gy range. The substantial risk of distant relapse in Stage I ocular adnexal MALT lymphoma underscores the importance of long-term follow-up for this disease and the need for additional comparative studies of MALT lymphoma of different anatomic sites.

[Treatment with charged particles beams: hadrontherapy part I: physical basis and clinical experience of treatment with protons]

Protons have physical characteristics, which differ from those of photons used in conventional radiotherapy. Better shielding of critical organs is obtained by using their particular ballistic (Bragg peak and lateral narrow penumbra). Some indications as ocular melanoma, chordoma and chondrosarcoma of the base of skull are now strongly accepted by the radiation oncologist community. Others are still in evaluation: meningioma, locally advanced nasopharynx tumor and paediatric tumors. The aim of this review is to present the clinical results of a technic which seems "confidential" because of the rarety and the cost of equipments.

[Blocking nociceptive afferents by retrobulbar bupivacaine does not decrease nausea and vomiting after propofol-remifentanil anaesthesia]

To test whether prophylactic neural blockade of noziceptive afferents or antiemetics diminutes postoperative nausea and vomiting (PONV) we studied in a randomised, prospective, and ouble-blind fashion 102 patients receiving implantation of an episcleral radioactive applicator for treatment of ocular malignant melanoma during remifentanil-propofol-anaesthesia.

METHODS

15 minutes prior to induction Dolasetron 12.5 mg (n = 18) or 50 mg (n = 20), Ondansetron 8 mg (n = 18), Droperidol 20 microg/kg (n = 23) or NaCl 0.9 % (n = 22) were randomly injected i.v. Furthermore, 4-8 ml Mepivacain 2 %/Bupivacain 0.5 % (n = 52) or saline (n = 50) were injected into the retrobulbar space after anaesthetic induction. Piritramid (0.1 mg/kg) was given for postoperative analgesia 30 minutes before end of surgery. Metamizol (1 g i.v.) and Dolasetron (12.5 mg i.v.) were provided on request as "rescue" medications. Variables were assessed by standardised questioning (NRS; yes/no) before and 1, 6, and 24 hours after surgery.

STATISTICS

Chi(2)-, Mann-Whitney-U-, Kruskal-Wallis-test and logistic regression analysis, p < 0.05.

RESULTS

Although retrobulbar anaesthesia decreased ocular pain (p = 0.013) and total postoperative complaints (p = 0.017) the incidence of PONV was not diminished. Droperidol was the only antiemetic to decrease PONV significantly (p = 0.001).

CONCLUSIONS

Although prophylactic blockade of nozizeptive afferents by retrobulbar anesthesia decreased ocular pain and postoperative complaints, it failed to decrease the incidence of PONV. Thus, PONV after ocular surgery under propofol-remifentanil anaesthesia is not attenuated by preoperative blockade of noziceptive afferents. In patients undergoing total intravenous anaesthesia with propofol-remifentanil, droperidol prevented PONV more effectively than the used serotonin receptor antagonists.