The value of lead shields in reducing radiation dosage to the eye during neuroradiological procedures

Home-made protective eyeshields are described, for use during certain types of skull radiography. Measurements made during the examination of patients and with a phantom skull indicate that a ten-fold reduction in radiation dose may be achieved through their use during certain diagnostic procedures.     

Craniofacial resection. An alternative incision and skull base repair

Neoplasia of the superior group of paranasal sinuses (frontal, ethmoidal and sphenoidal) has an extremely poor prognosis. Resection, preceded or followed by radiotherapy offers a 5 year survival of less than 30% (1). Satisfactory surgical excision has been undermined by difficulties of access to the cribriform plate area, a common site for residual disease. Furthermore the practice of piecemeal removal invariably resulted in inadequate clearance. The craniofacial approach allows not only excellent access to the anterior skull base but also in bloc excision. The results of treating 7 patients with craniofacial resection for tumours in this area are presented. Particular reference is made to a horizontal forehead skin crease incision for intracranial access. A new technique using a combination of surgical, pericranium, partial thickness skin and fibrin glue to repair the skull base defect is described.     

Quantitative cytomegalovirus (CMV) antigenaemia during antiviral treatment of AIDS-related CMV disease

Self-inflicted dermatoses are associated with personality disorders and psychoses, including monosymptomatic hypochondriacal psychosis (MHP), which is characterized by a delusion involving a particular hypochondriacal concern. We report an unusual case of MHP with severe mutilation of the skin complicated by a skull defect and brain abscess. The patient was a 66-year-old uneducated man who damaged his forehead repeatedly because he believed that a 'toxic root' in the forehead was the source of his general ailment. He admitted that the lesions were self-inflicted. There was no other evidence of psychosis or primary skin disease and MHP was diagnosed. Despite initial favourable response to pimozide, the patient was lost to follow-up for 4 years, during which he continued to damage his forehead and applied corrosive agents. He was then referred with a personality change and a 6 x 4 cm bony defect in the skull, complicated by herniation and abscess of the left frontal lobe. This case represents one of the most severe examples of self-mutilation ever reported. The differential diagnosis of dermatitis artefacta and the principles of treating MHP are discussed.     

A technique for fractionated stereotactic radiotherapy in the treatment of intracranial tumors

PURPOSE: The excellent treatment results obtained with traditional radiosurgery have stimulated attempts to broaden the range of intracranial disorders treated with radiosurgical techniques. For major users of radiosurgery this resulted in a gradual shift from treating vascular diseases in a single session to treating small, well delineated primary tumors on a fractionated basis. In this paper we present the technique currently used in Montreal for the fractionated stereotactic radiotherapy of selected intracranial lesions. METHODS AND MATERIALS: The regimen of six fractions given every other day has been in use for "fractionated stereotactic radiotherapy" in our center for the past 5 years. Our current irradiation technique, however, evolved from our initial method of using the stereotactic frame for target localization and first treatment, and a "halo-ring" with tattoo skin marks for the subsequent treatments. Recently, we developed a more precise irradiation technique, based on an in-house-built stereotactic frame which is left attached to the patient's skull for the duration of the fractionated regimen. Patients are treated with the stereotactic dynamic rotation technique on a 10 MV linear accelerator (linac). RESULTS: In preparation for the first treatment, the stereotactic frame is attached to the patient's skull and the coordinates of the target center are determined. The dose distribution is then calculated, the target coordinates are marked onto a Lucite target localization box, and the patient is placed into the treatment position on the linac with the help of laser positioning devices. The Lucite target localization box is then removed, the target information is tattooed on the patient's skin, and the patient is given the first treatment. The tattoo marks in conjunction with the target information on the Lucite target localization box are used for patient set-up on the linac for the subsequent 5 treatments. The location of the target center is marked with radio-opaque markers on the target localization box and verified with a computerized tomography scanner prior to the second treatment. The same verification is done prior to other treatments when the target center indicated by the target localization box disagrees with that indicated by the tattoo marks. The new position of the target center is then determined and used for treatment positioning. CONCLUSION: The in-house-built frame is inexpensive and easily left attached to the patient's skull for the 12 day duration of the fractionated regimen. Positioning with the Lucite target localization box verified with tattoo marks ensures a high level of precision for individual fractionated treatments.     

Measurement of off-axis and peripheral skin dose using radiochromic film

A radiotheraphy skin dose profile can be obtained with radiochromic film. The central axis skin dose relative to Dmax for a 10 x 10 cm2 field size was found to be 22%, 17% and 15.5% for 6 MV, 10 MV and 18 MV photon beams. Peripheral dose increased with increasing field size. At 10 MV the skin dose 2 cm outside the geometric field edge was measured as 6%, 10% and 17% for 10 x 10 cm2, 20 x 20 cm2 and 30 x 30 cm2 field sizes respectively. Off-axis skin dose decreased as distance increased from central axis for fields with Perspex block trays. For a 20 x 20 cm2 field, an approximately 5-8% drop in percentage skin dose was observed from central axis to the beam edge.     

The "ART" mandibular nerve block: a new approach to accomplishing regional anesthesia

A study was conducted from February 29, 1996, to March 28, 1996, at the University of Brno's Pathology Institute in the Czech Republic to explore the possible application of craniofacial intracranial endoscopic techniques through minimal skin incisions and trephines in fresh cadavers (3 to 12 hours old). Through the trephines the dura was totally dissected from the bone. After this dissection a standard bicoronal incision and a full craniotomy was performed to assess the integrity of the meninges. This minimally invasive dissection of the skull base with the aid of an endoscope is characterized by fewer skin incisions, thereby avoiding the exposure of subcutaneous tissue, muscle, cranial bone, and meninges. We find that it is possible to accomplish an accurate and extensive intracranial dissection with the aid of an endoscope. The potential of this technique is important for craniofacial surgery as well as for neurosurgery. The objectives of this study were [1] to explore endoscopically the craniofacial anatomy to determine the best approach and the optimal method for dissecting endocranial structures, and [2] to achieve a safer and more accurate dissection of the skull base, evaluating advantages of endoscopic surgery as an alternative method for the treatment of craniofacial and neurosurgical pathologies.     

Skin lycopene is destroyed preferentially over beta-carotene during ultraviolet irradiation in humans

This placebo-controlled study examined in healthy women the effects of ingestion of a single large dose of beta-carotene (120 mg) on the concentrations of beta-carotene and lycopene in plasma and skin, and the effects of UV light exposure on the concentrations of beta-carotene and lycopene in the skin. Ingestion of beta-carotene increased plasma beta-carotene concentration by 127%, from 0.26 +/- 0.06 (mean +/- SEM) to 0.59 +/- 0.07 mumol/L after 1 d, and the level remained elevated at 0.54 +/- 0.11 mumol/L after 5 d. beta-Carotene in skin, analyzed after 6 d, increased by 23%, from 1.41 +/- 0.74 to 1.74 +/- 0.72 nmol/g. beta-Carotene ingestion had no effect on the lycopene concentrations of plasma (0.37 +/- 0.11 mumol/L) or skin (1.60 +/- 0.62 nmol/g). A single exposure of a small area of one volar forearm to a dose of solar-simulated light (three times the individually determined minimal erythema dose) resulted in 31 to 46% reductions in skin lycopene concentration compared with an adjacent non-exposed area. The same UV dose did not result in significant changes in skin beta-carotene concentration. We conclude that a single 120-mg dose of beta-carotene increases plasma and skin beta-carotene concentrations and has no effect on plasma and skin lycopene concentrations. The amounts of lycopene in plasma and skin are comparable to or even greater than those of beta-carotene. When skin is subjected to UV light stress, more skin lycopene is destroyed compared with beta-carotene, suggesting a role of lycopene in mitigating oxidative damage in tissues.     

Striated osteopathy

Striated osteopathy, a roentgenological entity characterized by longitudinal striations, can occur concomitantly with a number of disorders which should be routinely looked for. There are three types of striated osteopathy. The pure form without severe bone disorders is the form originally reported by Voorhoeve. In the second form, there is a concomitant fibrous dysplasia, such as Jaffe-Lichtenstein-Uehlinger disease, Ollier enchondromatosis, sponastrism dysplasia, or osteopetrosis. This group also includes bone dysplasias with sclerosis such as melorheostosis, osteopecilia, and sclerosis of the base of the skull which is sometimes seen in patients with striated osteopathy. In the third form, striated osteopathy occurs concomitantly with a skin disease such as patchy dermal hypoplasia or hyperpigmented skin lesions.     

Bone regeneration by basic fibroblast growth factor complexed with biodegradable hydrogels

The objective of this study is to enhance the bone induction activity of basic fibroblast growth factor (bFGF) for reconstruction of skull bone defects which has been clinically recognized as almost impossible. For this purpose, we prepared biodegradable hydrogels from gelatin with an isoelectric point of 4.9 which is capable of polyionic complexing with basic bFGF. When implanted in rabbit skull defects of 6 mm in diameter (6 defects per experimental group), the gelatin hydrogels incorporating 100 microg of bFGF promoted bone regeneration at the defect in marked contrast to free bFGF of the same dose, finally closing the bone defects after 12 weeks of implantation as is apparent from histological examination. In dual energy X-ray absorptometry analysis, the bone mineral density at the skull defects enhanced by the hydrogels was significantly higher than that by free bFGF at doses ranging from 2 to 200 microg/defect (P < 0.05). The extent of bone regeneration induced by gelatin hydrogels incorporating 100 microg of bFGF increased with a decrease in their water content. Histological examination indicated that more slowly degrading hydrogels of lower water content prolonged the retention period of osteoblasts in the bone defects. This led to enhanced bone regeneration compared with faster degrading hydrogels of higher water content. It was concluded that this biodegradable hydrogel system was a promising surgical tool to assist self-reconstruction of the skull bone.     

Transcranial erosion of a benign dermal cylindroma

Dermal eccrine cylindroma is a benign adnexal tumor that commonly affects the scalp, neck, and face. Malignant transformation is rare and has resulted in several cases of intracranial invasion. There have been no previously reported cases of a benign lesion eroding through the skull vault. We report the development of such a lesion in a woman who had undergone total scalp excision and resurfacing with a split skin graft some 23 years earlier. Details of the case and its management are presented.     

Risk analysis of linear accelerator radiosurgery

PURPOSE: To evaluate the toxicity of stereotactic single-dose irradiation and to compare the own results with already existing risk prediction models. METHODS AND MATERIALS: Computed tomography (CT) or magnetic-resonance (MR) images, and clinical data of 133 consecutive patients treated with linear accelerator radiosurgery were analyzed retrospectively. Using the Cox proportional hazards model the relevance of treatment parameters and dose-volume relationships on the occurrence of radiation-induced tissue changes (edema, localized blood-brain barrier breakdown) were assessed. RESULTS: Sixty-two intraparenchymal lesions (arteriovenous malformation (AVM): 56 patients, meningioma: 6 patients) and 73 skull base tumors were selected for analysis. The median follow-up was 28.1 months (range: 9.0-58.9 months). Radiation-induced tissue changes (32 out of 135, 23.7%) were documented on CT or MR images 3.6-58.7 months after radiosurgery (median time: 17.8 months). The actuarial risk at 2 years for the development of neuroradiological changes was 25.8% for all evaluated patients, 38.4% for intraparenchymal lesions, and 14.6% for skull base tumors. The coefficient: total volume recieving a minimum dose of 10 Gy (VTREAT10) reached statistical significance in a Cox proportional hazards model calculated for all patients, intraparenchymal lesions, and AVMs. In skull base tumors, the volume of normal brain tissue covered by the 10 Gy isodose line (VBRAIN10) was the only significant variable. CONCLUSIONS: These results demonstrate the particular vulnerability of normal brain tissue to single dose irradiation. Optimal conformation of the therapeutic isodose line to the 3D configuration of the target volume may help to reduce side effects.     

Digital radiography in paediatrics: radiation dose considerations and magnitude of possible dose reduction

The purpose of this study was to evaluate the radiation doses received by paediatric patients examined using a digital radiography unit, and to compare these doses with those received from conventional screen-film systems. In this way, guidelines could be drawn up concerning the magnitude of possible dose reductions achievable using digital radiography. The study was undertaken on approximately 900 patients undergoing abdomen, chest, pelvis and skull examinations. Patients were categorized into the following age groups: 0-1 month, 1-12 months, 1-5 years, 5-10 years and 10-15 years. Approximately half were X-rayed using a Fuji computed radiography system and half using a conventional screen-film system. Entrance surface dose was calculated from the recorded exposure parameters and measured X-ray tube outputs. Dose-area product was recorded directly. Image quality was assessed clinically using criteria recommended by a working group of the Commission of the European Communities. Apart from chest examinations, it was found possible to reduce doses by about 40% on average, by using a computed radiography system instead of a 600 speed screen-film combination. There was no significant difference in the dose for chest examinations. Satisfactory image quality can therefore be achieved by using computed radiography as a 1000 speed system for abdomen, pelvis and skull examinations, and as a 600 speed system for chests. Since very few departments appear to use screen-film systems of speeds greater than 400, then, for most departments, the use of computed radiography would result in dose reductions of at least 60%, or 33% for chests.     

Clinical application of rhombotrapezious island musculocutaneous flap for skull base and/or craniomaxillary operation with malignant tumor

Regional pedicled musculocutaneous flaps are the mainstay of the head and neck reconstruction. They provide a rapid, highly reliable and single-staged technique that is applicable in most cases. The rhombotrapezious island musculocutaneous flap is valuable in the base and craniomaxilloface reconstruction. In this study we updated our experience with the rhombotrapezious island musculocutaneous flap (RTIMF) in 6 cases from 1989 to 1993. Dissections were performed on 9 cadavers, 4 preserved and 5 fresh, yielding 18 pairs or dorsal scapular and transverse cervical artery for evaluation. In the five fresh cadavers, the arteries were selectively cannulated and injected with colored latex. 67% with dorsal scapular and transverse cervical artery commonly arose from the thyro-cervical trunk. 33% with the dorsal scapular artery directly arose from the second part of the subclavian artery. In the period of 1989-1993, 6 rhombotrapezious island musculocutaneous flaps with vascularized pedicle were used for immediate repair in the skull base or craniomaxillary cancer operations. There was no complication of the flaps. Donor site complications were relatively minor. The disturbance in shoulder function was well tolerated. We advocated the incorporation of both the greater and lesser rhomboid muscle to form the compound rhombotrapezious flaps to enhance the vascular supply to the overlying skin. The major advantage of the RTIMF are that it provides a long paddle of thin pliant, hairless skin and muscle that can be rotated as far as the craniomaxilloface and scalp in a single stage. It offers the longest arc of rotation and thus the greatest versatility for the skull base or craniomaxillary reconstruction.     

Indications for, contraindications to, and interruption of craniofacial procedures

In spite of increasing experience with skull base surgery, some of the guidelines for indications for operations may vary according to the institution. One-hundred two patients underwent craniofacial oncologic resections at our institution from 1982 to 1995. A retrospective analysis of the indications for and contraindications to these procedures was undertaken. The main indications for malignant tumors were skin lesions with direct invasion of the anterior or lateral skull base (69%) and nasal-paranasal sinus tumors (21%). The main indications for benign tumors were glomus lesions (26%), menigiomas (22%), and fibro-osseous lesions of the anterior skull base (19%). The main contraindications were extensive invasion of the central nervous system, invasion of the cavernous sinus and/or internal carotid artery by aggressive malignancies, and bilateral orbital invasion in a nonblind patient. Also, 6 patients had their procedures interrupted during craniotomy for several reasons - extensive central nervous system invasion (2 cases), bilateral orbital invasion (1), lack of brain retraction (1), lack of histologic diagnosis during the operation (1), and purulent discharge at the frontal sinus (1). Craniofacial oncologic operations are extensive surgical procedures that have to be properly indicated in order to obtain low levels of morbidity and mortality. The selection of cases is of paramount importance. In some instances, it seems advisable even to interrupt these operations in the first phase.     

Cloning of the gene for spinocerebellar ataxia 2 reveals a locus with high sensitivity to expanded CAG/glutamine repeats

A 3-day monolithic polyacrylate adhesive dispersion type delivery system containing methadone was fabricated and in vitro permeation through hairless mouse and human cadaver skins was conducted. The effect of skin permeation enhancers was also investigated. Skin permeation rate across human cadaver skin was found to be lower than that of hairless mouse. Skin permeation profiles across both types of skins showed a membrane permeation controlled cumulative amount permeated (Q) versus time (t) relationship. Skin permeation rate was found to be dependent on both adhesive film thickness and loading dose of the drug in the matrix. Effective skin permeation rate across the hairless mouse skin was obtained from a patch with 1.5 mm thickness and 15% w/w loading dose. n-Decylmethyl sulfoxide and Azone were found to produce an effective skin permeation rate of methadone through human cadaver skin at a 5% w/w concentration. These initial studies demonstrated the feasibility of methadone administration through intact skin from a transdermal patch.     

Follow-up study of patients treated by x-ray epilation for tinea capitis. Estimation of the dose to the thyroid and pituitary glands and other structures of the head and neck

This study is a further investigation of radiation dose to various head structures in the children given X-ray therapy for tinea capitis (ringworm of the scalp). In this work, estimates of the dose to the thyroid and pituitary gland were obtained with lithium fluoride thermoluminescent dosemeters using a child's head phantom. Doses were also measured for the parotid gland and several skin sites where skin tumours developed in the irradiated cases. In a previous study, brain and scalp doses of 140 and 500-800 rad had been estimated for the treated group using this same head phantom. In this work dosemeters were also placed in the same brain locations so that comparisons could be obtained between the two studies. The thyroid dose was estimated to be 6 +/- 2 rad and the pituitary dose was 49 +/- 6 rad for the conventional tinea capitis treatment. The dose to the parotid gland was 39 rad and the dose to skin sites on the face and neck where tumours occurred ranged from 20 to 40 rad. The data for the thyroid adenoma response from this and other studies involving irradiation of children suggests a linear dose-response relationship within the first 30-40 years after exposure with a risk of about 0-04% per rad.     

CO2 laser debridement of sulphur mustard (bis-2-chloroethyl sulphide) induced cutaneous lesions accelerates production of a normal epidermis with elimination of cytological atypia

Sulphur mustard (bis-2-chloroethyl sulphide; HD) exposure acutely produces lesions that vary from mild erythema, to blister formation, to necrosis. When blisters occur, with or without necrosis, healing of the lesions is delayed. Weanling pigs exposed to a mild erythema-producing dose of HD and to a moderate erythema-producing dose that consistently gave microblister formation were treated with CO2 laser (Tru-Pulse) debridement at 6, 24 or 48 h after exposure. The histopathological features observed at 14 days after exposure in control skin and skin exposed to both HD doses were compared with the features observed in CO2 laser-debrided skin in non-exposed and HD-exposed skin sites. The overlying epidermis in the non-laser treated lesions was thin, with cytological atypia and squamoid changes within the basal cell layer, as well as scattered apoptotic/necrotic keratinocytes. An increased inflammatory infiltrate and necrobiotic changes in the dermis were seen at the higher HD dose. All laser-treated lesions appeared identical, with a thick, differentiated epidermis and a well-formed basal cell layer. There was minimal inflammatory infiltrate. In the papillary dermis there were increased stromal cells. Laser debridement of mild clinical lesions induced by HD produced a more functional epidermis by 14 days as well as clearing the epidermis of damaged keratinocytes.     

Assessment of skin types, skin colours and cutaneous responses to ultraviolet radiation in an Asian population

Ninety normal individuals were included in this study on skin types, skin colours and cutaneous responses to ultraviolet radiation. Skin types were recorded using Fitzpatrick's classification, skin colours were measured using the Minolta Chromameter CR-300, and cutaneous responses to UV radiation were measured in terms of minimal erythema dose (MED) to UVA, UVB and the immediate pigment darkening dose to UVA (IPDDA). Skin colour measurements were taken from the right cheek to represent facultative skin colours, and from the buttock to represent constitutive skin colours. The colours measured were expressed by the L x a x b colour space. Skin types and some colour parameters (L and b from covered parts of body) correlated fairly well with the minimal erythema doses (MED) to UVA and UVB. Skin colour measurements are more objective than skin type assessment and could be better markers of photosensitivity. However, there is still considerable overlap in MEDs for persons with different skin colours, and further studies of these parameters are warranted. Our MEDs are higher than other reports on similar skin types and skin colours. This could be due to differences in methodology, genetic make-up or acclimatization from chronic sun exposure. This illustrates the importance of local controls for each institution dealing with photosensitive disorders.     

Real-time measurement of skin radiation during cardiac catheterization

A novel skin dose monitor was used to measure radiation incident on maximal X-ray exposed skin during 135 diagnostic and 65 interventional coronary procedures. For the diagnostic studies (n = 135), mean skin dose was 180 +/- 64 mGy; for PTCA (n = 35), it was 1021 +/- 674 mGy, single stents (n = 25) 1529 +/- 601 mGy, and multiple stents with rotational atherectomy (n = 5) 2496 +/- 1028 mGy. The dose independently increased with more cine runs, more fluoroscopy, and greater patient weight. Physicians should consider the potential for adverse radiation exposure when planning coronary interventional cases and deciding on the X-ray mode and angles used.