Permanent Epilation Research Articles

Proton minibeam radiation therapy spares normal rat brain: Long-Term Clinical, Radiological and Histopathological Analysis

Proton minibeam radiation therapy (pMBRT) is a novel strategy for minimizing normal tissue damage resulting from radiotherapy treatments. This strategy partners the inherent advantages of protons for radiotherapy with the gain in normal tissue preservation observed upon irradiation with narrow, spatially fractionated beams. In this study, whole brains (excluding the olfactory bulb) of Fischer 344 rats (n = 16) were irradiated at the Orsay Proton Therapy Center. Half of the animals received standard proton irradiation, while the other half were irradiated with pMBRT at the same average dose (25 Gy in one fraction). The animals were followed-up for 6 months. A magnetic resonance imaging (MRI) study using a 7-T small-animal MRI scanner was performed along with a histological analysis. Rats treated with conventional proton irradiation exhibited severe moist desquamation, permanent epilation and substantial brain damage. In contrast, rats in the pMBRT group exhibited no skin damage, reversible epilation and significantly reduced brain damage; some brain damage was observed in only one out of the eight irradiated rats. These results demonstrate that pMBRT leads to an increase in normal tissue resistance. This net gain in normal tissue sparing can lead to the efficient treatment of very radio-resistant tumours, which are currently mostly treated palliatively.

Initial experience with high dose rate brachytherapy of periorbital sarcoids in the horse

SummaryPeriorbital sarcoids are a common condition in the horse and are difficult to treat due to their location and invasive nature. Radiotherapy is considered the gold standard treatment, and high dose rate brachytherapy (HDRB) may represent a safer and more effective method of delivering radiotherapy in the standing sedated horse. The objective of this retrospective clinical case series study was to describe the response rate and safety of HDRB for the treatment of periorbital sarcoids in the horse. Horses and ponies referred for HDRB treatment of confirmed periorbital sarcoids were eligible for inclusion in the study. Sarcoids were confirmed via clinical diagnosis and biopsy. Horses were given 2 fractions of 12.5 Gy per fraction, delivered a week apart, under standing sedation via a novel HDRB technique. Eight horses with periorbital sarcoids were treated with HDRB under standing sedation. A complete response occurred in all cases. No significant acute adverse effects were noted after treatment and the cosmetic result was excellent, with permanent epilation and leucotrichia the only long‐term sequelae. Follow‐up was available for between 10 and 12 months after treatment. The major limitation of this study is the lack of long‐term follow‐up and the small case numbers. It was concluded that HDRB appears to be an effective and safe method of treating periorbital sarcoids in the horse. Long‐term follow‐up is required to determine the risk of recurrence of treated lesions.

SU‐G‐TeP3‐09: Proton Minibeam Radiation Therapy Increases Normal Tissue Resistance

Purpose:The dose tolerances of normal tissues continue being the main limitation in radiotherapy. To overcome it, we recently proposed a novel concept: proton minibeam radiation therapy (pMBRT) [1]. It allies the physical advantages of protons with the normal tissue preservation observed when irradiated with submillimetric spatially fractionated beams (minibeam radiation therapy) [2]. The dose distributions are such that the tumor receives a homogeneous dose distribution, while normal tissues benefit from the spatial fractionation of the dose. The objective of our work was to implement this promising technique at a clinical center (Proton therapy center in Orsay) in order to evaluate the potential gain in tissue sparing.Methods:Dose distributions were measured by means of gafchromic films and a PTW microdiamond detector (60019). Once the dosimetry was established, the whole brain of 7 weeks old male Fischer 344 rats was irradiated. Half of the animals received conventional seamless proton irradiation (25 Gy in one fraction). The other rats were irradiated with pMBRT (58 Gy peak dose in one fraction). The average dose deposited in the same targeted volume was in both cases 25 Gy.Results:The first complete set of dosimetric data in such small proton field sizes was obtained [3]. Rats treated with conventional proton irradiation exhibited severe moist desquamation and permanent epilation afterwards. The minibeam group, on the other hand, exhibited no skin damage and no clinical symptoms. MRI imaging and histological analysis are planned at 6 months after irradiation.Conclusion:Our preliminary results indicate that pMBRT leads to an increase in tissue resistance. This can open the door to an efficient treatment of very radioresistant tumours. [1] Prezado et al. Med. Phys. 40, 031712, 1–8 (2013).[2] Prezado et al., Rad. Research. 184, 314‐21 (2015). [3] Peucelle et al., Med. Phys. 42 7108‐13 (2015).

Radiation-induced skin injury after complex endovascular procedures

Radiation-induced skin injury is a serious potential complication of fluoroscopically guided interventions. Transient erythema occurs at doses of 2 to 5 Gy, whereas permanent epilation, ulceration, and desquamation are expected at doses above this level. Complex endovascular procedures (CEPs), such as fenestrated endovascular aortic aneurysm repair (FEVAR), are associated with high radiation doses, yet the prevalence of radiation-induced skin injury is unknown. We hypothesized that skin injury after these exposures is likely to be underrecognized and underreported. This study examined the frequency and severity of deterministic effects and evaluated patient characteristics that might predispose to radiation injury in CEP. CEP was defined as a procedure with a radiation dose ≥5 Gy (National Council on Radiation Protection and Measurements threshold for substantial radiation dose level [SRDL]). Radiation dose and operating factors were recorded for all CEPs performed in a hybrid room during a 30-month period. Patient medical records were retrospectively reviewed for evidence of skin injury. Patients were seen in follow-up daily until discharge and then at weeks 2 and 6, months 3 and 6, and 1 year. Phone interviews were conducted to determine the presence of any skin-related complaints. Peak skin dose (PSD) distributions were calculated for FEVARs with custom software employing input data from fluoroscopic machine logs. These calculations were validated against Gafchromic film (Ashland Inc, Covington, Ky) measurements. Dose was summed for the subset of patients with multiple procedures within 6 months of the SRDL event, consistent with Joint Commission recommendations. Sixty-one CEPs reached a reference air kerma (RAK) of 5 Gy (50 FEVARs, six embolizations, one thoracic endovascular aortic repair, one endovascular aneurysm repair, one carotid intervention, and two visceral interventions). The patient cohort was 79% male and had a mean body mass index of 31. The average RAK was 8 ± 2 Gy (5.0-15.9 Gy). Sixteen patients had multiple CEPs within 6 months of the SRDL event, with a mean cumulative RAK of 12 ± 3 Gy (7.0-18.4 Gy). The mean FEVAR PSD was 6.6 ± 3.6 Gy (3.7-17.8 Gy), with a mean PSD/RAK ratio of 0.78. Gafchromic film dose measurements were not statistically different from PSD estimations, with a constant of proportionality of 0.99. Three patients were lost to follow-up before their first postoperative visit. No radiation skin injuries were found. This study represents the largest analysis of deterministic skin injury after CEPs, and our results suggest that it is less frequent than expected and not increased in CEPs.

Photo-Epilation: Guidelines for care from the European Society for Laser Dermatology (ESLD)

Laser- or flashlamp- (also called intense pulsed light source or IPLS) assisted hair removal is a well tolerated and effective technique for patients who desire permanent reduction of hair growth. Although laser and light sources are very popular because of their non-invasive nature and the speed at which they operate, practitioners and patients have to be cautious to avoid permanent side effects instead of permanent hair reduction. These guidelines focus on patient selection and treatment protocol in order to provide safe and effective treatment. The ideal patient for laser hair removal is light skin with black coarse hair. Blond, grey and white hair does not respond to treatment. Individuals with dark skin, and especially tanned patients, are at higher risk for pigmentary changes. Sunscreen before and after treatment will produce and maintain untanned skin. The type of laser or IPLS and their specific parameters must be adapted to the patient (hair thickness, pigment concentration, Fitzpatrick skin type). Treatments should start on a test patch and a treatment grid can improve accuracy. Pre-, parallel and post-cooling, as well as a reduction of the fluence, will prevent adverse effects such as pigment alteration and scar formation. Average rates of long-term hair reduction are reported at between 70% and 90% at 6 months follow-up. At least three repeated treatments should be done to achieve partly permanent epilation.

Improvements in technique for whole-brain irradiation

1539 Background: Brain metastases are commonly addressed with whole-brain irradiation, using unblocked opposed lateral fields, delivering 30 Gy in 10 fractions via 6 MV photons prescribed to midplane, with the isocenter set in the center of the cranial contents. A frequent result in long term survivors is permanent partial epilation in a strip of skin along the skull apex, a so-called “reverse Mohawk”. The object of our study was to determine if simple measures would be able to decrease radiation dose in this region at risk. We also investigated the dose delivered to the lens. Methods: A 6-cm wide, 4-mm thick strip of scalp on the top of the head, and bilateral lenses were contoured using the ADAC treatment planning system. Data from five patients undergoing CT simulation for brain irradiation were used for dose measurements. We investigated the dosimetry with an open-field whole-brain set up (WB), with a 1-cm inferior margin below all brain tissue, whole-brain set up with a scalp block drawn 1-cm external to the inner table of the skull (WBB), whole-brain set up with half beam (HB), with the isocenter at the inferior border and whole-brain set up with half beam with the same scalp block (HBB). To verify relative doses to regions of the scalp, dose was measured at representative points in a phantom, using thermoluminescent detectors (TLD) placed under a 3-mm slab of bolus to match the depth of hair follicles. Results: The percent of the scalp strip receiving > 90% of the prescribed dose for each set up was WB 16.4%, WBB 9.5%, HB 12.8% and HBB 4.8%. Dose to the whole brain was not affected. TLD measurements with the phantom confirmed that the top of the scalp received 22% more dose than the sides of the head. The percentage of the total dose delivered to the lenses with each technique was WB 78.6%, WBB 20.5%, HB 80% and HBB 15.1%. Conclusions: Dose to the strip of scalp at risk for permanent epilation from whole-brain irradiation is reduced by using a half-beam technique, and conformal blocking 1-cm external to the inner table of the skull. Both of these changes in technique also reduce lens dose while ensuring that the whole brain is adequately irradiated. This approach prevents development of the “reverse Mohawk” and can improve quality of life. No significant financial relationships to disclose.

Improvements in technique for whole-brain irradiation

1539 Background: Brain metastases are commonly addressed with whole-brain irradiation, using unblocked opposed lateral fields, delivering 30 Gy in 10 fractions via 6 MV photons prescribed to midplane, with the isocenter set in the center of the cranial contents. A frequent result in long term survivors is permanent partial epilation in a strip of skin along the skull apex, a so-called “reverse Mohawk”. The object of our study was to determine if simple measures would be able to decrease radiation dose in this region at risk. We also investigated the dose delivered to the lens. Methods: A 6-cm wide, 4-mm thick strip of scalp on the top of the head, and bilateral lenses were contoured using the ADAC treatment planning system. Data from five patients undergoing CT simulation for brain irradiation were used for dose measurements. We investigated the dosimetry with an open-field whole-brain set up (WB), with a 1-cm inferior margin below all brain tissue, whole-brain set up with a scalp block drawn 1-cm external to the inner table of the skull (WBB), whole-brain set up with half beam (HB), with the isocenter at the inferior border and whole-brain set up with half beam with the same scalp block (HBB). To verify relative doses to regions of the scalp, dose was measured at representative points in a phantom, using thermoluminescent detectors (TLD) placed under a 3-mm slab of bolus to match the depth of hair follicles. Results: The percent of the scalp strip receiving > 90% of the prescribed dose for each set up was WB 16.4%, WBB 9.5%, HB 12.8% and HBB 4.8%. Dose to the whole brain was not affected. TLD measurements with the phantom confirmed that the top of the scalp received 22% more dose than the sides of the head. The percentage of the total dose delivered to the lenses with each technique was WB 78.6%, WBB 20.5%, HB 80% and HBB 15.1%. Conclusions: Dose to the strip of scalp at risk for permanent epilation from whole-brain irradiation is reduced by using a half-beam technique, and conformal blocking 1-cm external to the inner table of the skull. Both of these changes in technique also reduce lens dose while ensuring that the whole brain is adequately irradiated. This approach prevents development of the “reverse Mohawk” and can improve quality of life. No significant financial relationships to disclose.

Abstract: Avoidance of radiation injuries from medical interventional procedures, ICRP Publication 85

Interventional radiology (fluoroscopically-guided) techniques are being used by an increasing number of clinicians not adequately trained in radiation safety or radiobiology. Many of these interventionists are not aware of the potential for injury from these procedures or the simple methods for decreasing their incidence. Many patients are not being counselled on the radiation risks, nor followed up when radiation doses from difficult procedures may lead to injury. Some patients are suffering radiation-induced skin injuries and younger patients may face an increased risk of future cancer. Interventionists are having their practice limited or suffering injury, and are exposing their staff to high doses. In some interventional procedures, skin doses to patients approach those experienced in some cancer radiotherapy fractions. Radiation-induced skin injuries are occurring in patients due to the use of inappropriate equipment and, more often, poor operational technique. Injuries to physicians and staff performing interventional procedures have also been observed. Acute radiation doses (to patients) may cause erythema at 2 Gy, cataract at 2 Gy, permanent epilation at 7 Gy, and delayed skin necrosis at 12 Gy. Protracted (occupational) exposures to the eye may cause cataract at 4 Gy if the dose is received in less than 3 months, at 5.5 Gy if received over a period exceeding 3 months. Practical actions to control dose to the patient and to the staff are listed. The absorbed dose to the patient in the area of skin that receives the maximum dose is of priority concern. Each local clinical protocol should include, for each type of interventional procedure, a statement on the cumulative skin doses and skin sites associated with the various parts of the procedure. Interventionists should be trained to use information on skin dose and on practical techniques to control dose. Maximum cumulative absorbed doses that appear to approach or exceed 1 Gy (for procedures that may be repeated) or 3 Gy (for any procedure) should be recorded in the patient record, and there should be a patient follow-up procedure for such cases. Patients should be counselled if there is a significant risk of radiation-induced injury, and the patient's personal physician should be informed of the possibility of radiation effects. Training in radiological protection for patients and staff should be an integral part of the education for those using interventional techniques. All interventionists should audit and review the outcomes of their procedures for radiation injury. Risks and benefits, including radiation risks, should be taken into account when new interventional techniques are introduced. A concluding list of recommendations is given. Annexes list procedures, patient and staff doses, a sample local clinical protocol, dose quantities used, and a procurement checklist.

Technik und Langzeitergebnisse der Kryoepilation bei Trichiasis und Distichiasis

The present paper communicates the technique and results of cryoepilation in 1,690 cases (94% trichiasis and 6% distichiasis). Only nitrogen cryotherapy devices are totally suitable for this, and the spray freezing method is to be preferred. The IKG unit developed by the authors, which has proved successful in particular for tumor therapy, is also ideal for cryoepilation. It generates a very tightly bundled nitrogen spray jet, thus permitting isolated freezing of the lid margin. In about 95% of the cases permanent epilation is achieved without undue trauma. In 5% the condition described by Fraunfelder as "secondary trichiasis" develops. Ocular pemphigoid is not a contraindication to cryotherapy.

Soft-tissue reactions following irradiation of primary brain and pituitary tumors

One hundred and ninety-nine patients who received radiation therapy for a primary brain or pituitary tumor were studied for radiation-induced soft-tissue reactions of the cranium, scalp, ears and jaw. The frequency of these reactions was studied as a function of. the radiation dose 5 mm below the skin surface, dose distribution, field size and fraction size. Forty percent of patients had complete and permanent epilation, while 21% had some other soft-tissue complication, including scalp swelling—6%, external otitis—6%, otitis media—5%, ear swelling—4%, etc. The frequency of soft-tissue reactions correlates directly with the radiation dose at 5 mm below the skin surface. Patients treated with small portals (<70 cm 2) had few soft-tissue reactions. The dose to superficial tissues, and hence the frequency of soft-tissue reactions can be reduced by: (1) using high-energy megavoltage beams; (2) using equal loading of beams; and (3) possibly avoiding the use of electron beams.

Epilation by Electrocoagulation: Factors that Result in Regrowth of Hair

From our experience, the most important requirement for permanent epilation by electrocoagulation is not only to destroy hair bulbs, but also to destroy the isthmal regions of hair follicles and the sebaceous glands.

Inductive capacity of irradiated dermal papillae.

MAMMALIAN hair follicles are specialised skin appendages which produce a series of hairs, one after another, in a regular cyclical fashion. The hair itself is composed of dead epithelial cells containing large amounts of keratin. During growth of the hair the epithelial cells at the bottom of the follicle surround the dermal papilla and divide rapidly. The dermal papilla is derived from mesenchyme and is composed of non-dividing cells. The importance of the dermal papilla in maintenance and control of hair cycles has been assumed for many years but little direct evidence of its function has been demonstrated. Geary1 caused permanent removal of rat body hair by applying 1,720 rad of X irradiation. He believed that he had caused destruction of the dermal papilla which in turn resulted in permanent epilation. We report here a study on the effect of heavy doses of irradiation on the dermal papilla and epithelial elements of the hair follicle. We have found that high doses of irradiation, which cause permanent epilation, destroy the epithelium but leave the dermal papilla anatomically and functionally intact so that even on transplantation it can induce a series of new hairs.

Skin response to X-irradiation in the guinea-pig.

Skin reaction to X-irradiation has been studied in the albino guinea-pig; early response in limited-field irradiations of the flank is comparable to that commonly seen in rodents, swine and man, and is dose-dependent with a dynamic range from mild erythema to moist desquamation. The peak early skin reaction is seen between 14 and 21 days after irradiation, and declines before 30 days except at the highest doses used. Fractionation of the X-ray dose at 24 hours results in a 'sparing' of about 340 rad. Permanent partial epilation is detectable at doses in excess of 1400 rad, and complete epilation at 1 year occurs in 50 per cent of irradiated fields at 1740 rad. Twenty-four hour two-dose fractionation results in a 'sparing' of about 500 rad for epilation. Palpable dermal 'fibrosis' is detectable at 3 months after irradiation in fields given more than 2070 rad, and at 1 year after irradiation in fields given more than 1800 rad; 50 per cent of fields showed palpable 'fibrosis' at 1 year at 1930 rad. Unlike domestic swine and man, skin fields in the guinea-pig showed no dimensional contraction after X-ray doses which produced gross early skin damage.

Epilaiton and Hair Greying in Hamsters Following one Single Application of Beta Rays

Syrian golden and white hamsters were exposed to a single application of beta rays from a Krypton 85 source in doses of 2,000, 4,000 and 10,000 rads. Permanent epilation was observed in Golden hamsters receiving the highest dose, permanent graying of hair was observed in lower doses. In white hamsters, permanent epilation occurred at lower doses than those for golden hamsters. Intense atrophy of the epidermis was observed histologically in animal's skin exposed to highest doses. A relatively higher mortality rate was observed in animals receiving higher doses of radiation. No spreading of the hair-greying effect of beta rays was observed in this experiment.

The Effects of X-Rays on the Regrowth of Hair in the Mouse and Their Modification by Cysteamine

The mouse hair follicle was used as a biological model for studying relatively long-term radiation effects and for evaluating radioprotective agents. The flank hair was plucked 3 days before irradiation, and four areas were given exposures of varying magnitude (500 to 5000 R). It was found that the delay in regrowth and the permanent damage (at 100 days postirradiation and later) increased with increasing exposure. The effect of cysteamine in protecting the hair follicle was to diminish the delay of regrowth and the degree of permanent epilation, though the general character of the response was unchanged. The dose-reduction factor appeared to diminish with increasing dose of radiation. A tentative explanation for this finding, based on the hypothesis of there being some hypoxic cells present, is suggested. The advantages of this type of nondestructive radiobiological model are discussed.

Geometric Relationships Between the Matrix of the Hair Bulb and its Dermal Papilla in Normal and Alopecic Scalp

The growth of hair appears to be intimately dependent upon the connective tissue papilla enveloped by the hair bulb. Lillie and Wang (1) have shown that the feather of chickens, an appendage analogous to hair in mammals, fails to grow when the dermal papilla is removed. Wol-bach (2) has observed that the matrix of the hair in mice does not differentiate, nor does proliferation of hair occur, if the cells of the papilla are destroyed with benzpyrene or methylcholan-threne even though the remaining portions of the pilosebaceous structure survive. Geary (3), studying the effects of various doses of x-rays on the growth of hair in rats, found that permanent epilation results when the hair papilla is destroyed.

RINGWORM OF THE SCALP

During the last thirty-eight years, ringworm of the scalp has been the bane of the institution with which I am associated. There have been from six to forty cases of this condition. Every remedy that could be suggested was tried. Probably the best treatment, until roentgenotherapy was used, was Jackson's iodine and goose grease. With the advent of the roentgen ray, hope was entertained that this disease might be eradicated. Practically every patient treated by the one treatment plan was cured. It was sometimes difficult to get the parent's consent to the use of the roentgen ray, and the admission of new children kept up the infection. Partial alopecia resulted in one or two cases, and in one case, almost complete permanent epilation resulted. The fear of this distressing outcome seems to have made the roentgen-ray department of Cook County Hospital so cautious that for months from twenty-five to thirty