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Biomedical subjects

M Hossain

Publications and source records attributed to M Hossain.

At least 55 records · Page 3Linked to original sources
PubMed2001

Effects of erbium, chromium:YSGG laser irradiation on root surface: morphological and atomic analytical studies.

OBJECTIVE: The purpose of this study was to investigate the morphological and atomic changes on the root surface by stereoscopy, field emission-scanning electron microscopy (FE-SEM), and energy dispersive X-ray spectroscopy (SEM-EDX) after erbium, chromium:yttrium, scandium, gallium, garnet (Er,Cr:YSGG) laser irradiation in vitro. SUMMARY BACKGROUND DATA: There have been few reports on morphological and atomic analytical study on root surface by Er,Cr:YSGG laser irradiation. METHODS: Eighteen extracted human premolar and molar teeth were irradiated on root surfaces at a vertical position with water-air spray by an Er,Cr:YSGG laser at the parameter of 5.0 W and 20 Hz for 5 sec while moving. The samples were then morphologically observed by stereoscopy and FE-SEM and examined atomic-analytically by SEM-EDX. RESULTS: Craters having rough but clean surfaces and no melting or carbonization were observed in the samples. An atomic analytical examination showed that the calcium ratio to phosphorus showed no significant changes between the control and irradiated areas (p > 0.01). CONCLUSIONS: These results showed that the Er,Cr:YSGG laser has a good cutting effect on root surface and causes no burning or melting after laser irradiation.

Calcium↗
PubMed2001

Effect of pulsed Nd:YAG laser irradiation on acid demineralization of enamel and dentin.

OBJECTIVE: The purpose of this study was to investigate the effect of Nd:YAG laser irradiation on the acid demineralization of enamel and dentin by spectrophotometry. A mechanism of acquired acid resistance is also proposed. SUMMARY BACKGROUND DATA: The ability of Nd:YAG laser irradiation to the enhanced resistance to artificial caries formation is still controversial. METHODS: A pulsed Nd:YAG laser at 1.064-micron wavelength was used to irradiate the human enamel and dentin samples from 20 extracted human molars at the parameters of 1, 2, and 3 W and 20 pps for a total of 9 sec after painting with black ink. Samples were then subjected to 2 microliters of 0.1 M lactic acid solution (pH 4.8) for 24 h at 36 degrees C. The parts per million (ppm) of calcium ion (Ca2+) dissolved in each solution was determined by atomic absorption spectrophotometry and the morphological changes were also investigated by scanning electron microscopy (SEM). RESULTS: The lowest mean Ca2+ ppm was recorded in the samples irradiated at 3 W, in those by irradiated at 2 W and 1 W. The unlased samples showed the highest Ca2+ ppm. SEM observation showed that in the lased areas, the smear layer was partially melted and the underlying primary enamel or dentin seemed to be thermally degenerated. CONCLUSIONS: The results of this study suggested that melted smear layer and underlying enamel or dentin degenerated thermally by the heat treatment of Nd:YAG laser might play a major role to enhance resistance to artificial caries-like formation.

Calcium↗
PubMed2001

Analysis of surface roughness of enamel and dentin after Er,Cr:YSGG laser irradiation.

OBJECTIVE: The purpose of this investigation was to compare the surface roughness of enamel and dentin following the Er,Cr:YSGG laser irradiation and acid etching. BACKGROUND DATA: Laser-roughened enamel or dentin surfaces have been expected to enhance restorative materials bond strength. MATERIALS AND METHODS: Er,Cr:YSGG laser irradiation was performed in one half of each polished enamel or dentin sample at 3 W (33.9 J/cm2, with air 70% and water 20%,) pulse energy for 6 sec. Then the other half was treated with 37% phosphoric acid for 30 sec. Surface roughness and morphological studies were performed. RESULTS: It was found that surface roughness was significantly increased with the laser system. Scanning electron microscopy analysis showed that irradiated surface produces a rough surface that was completely lacking of a smear layer; there was also no cracking of enamel or dentin. CONCLUSION: Er,Cr:YSGG laser irradiation could provide an effective and alternative method to the acid etch technique.

Acids↗
PubMed2001

Comparison of surgical outcomes between teaching and nonteaching hospitals in the Department of Veterans Affairs.

OBJECTIVE: To determine whether the investment in postgraduate education and training places patients at risk for worse outcomes and higher costs than if medical and surgical care was delivered in nonteaching settings. SUMMARY BACKGROUND DATA: The Veterans Health Administration (VA) plays a major role in the training of medical students, residents, and fellows. METHODS: The database of the VA National Surgical Quality Improvement Program was analyzed for all major noncardiac operations performed during fiscal years 1997, 1998, and 1999. Teaching status of a hospital was determined on the basis of a background and structure questionnaire that was independently verified by a research fellow. Stepwise logistic regression was used to construct separate models predictive of 30-day mortality and morbidity for each of seven surgical specialties and eight operations. Based on these models, a severity index for each patient was calculated. Hierarchical logistic regression models were then created to examine the relationship between teaching versus nonteaching hospitals and 30-day postoperative mortality and morbidity, after adjusting for patient severity. RESULTS: Teaching hospitals performed 81% of the total surgical workload and 90% of the major surgery workload. In most specialties in teaching hospitals, the residents were the primary surgeons in more than 90% of the operations. Compared with nonteaching hospitals, the patient populations in teaching hospitals had a higher prevalence of risk factors, underwent more complex operations, and had longer operation times. Risk-adjusted mortality rates were not different between the teaching and nonteaching hospitals in the specialties and operations studied. The unadjusted complication rate was higher in teaching hospitals in six of seven specialties and four of eight operations. Risk adjustment did not eliminate completely these differences, probably reflecting the relatively poor predictive validity of some of the risk adjustment models for morbidity. Length of stay after major operations was not consistently different between teaching and nonteaching hospitals. CONCLUSION: Compared with nonteaching hospitals, teaching hospitals in the VA perform the majority of complex and high-risk major procedures, with comparable risk-adjusted 30-day mortality rates. Risk-adjusted 30-day morbidity rates in teaching hospitals are higher in some specialties and operations than in nonteaching hospitals. Although this may reflect the weak predictive validity of some of the risk adjustment models for morbidity, it may also represent suboptimal processes and structures of care that are unique to teaching hospitals. Despite good quality of care in teaching hospitals, as evidenced by the 30-day mortality data, efforts should be made to examine further the structures and processes of surgical care prevailing in these hospitals.

Education, Medical, Graduate↗
PubMed2001

Diagnosis and management of febrile children using the WHO/UNICEF guidelines for IMCI in Dhaka, Bangladesh.

OBJECTIVE: To determine whether the fever module in the WHO/UNICEF guidelines for the integrated management of childhood illness (IMCI) identifies children with bacterial infections in an area of low malaria prevalence. METHODS: Physicians assessed a systematic sample of 669 sick children aged 2-59 months who presented to the outpatient department of Dhaka Shishu Hospital, Bangladesh. FINDINGS: Had IMCI guidelines been used to evaluate the children, 78% of those with bacterial infections would have received antibiotics: the majority of children with meningitis (100%), pneumonia (95%), otitis media (95%) and urinary tract infection (83%); and 50% or less of children with bacteraemia (50%), dysentery (48%), and skin infections (30%). The current fever module identified only one additional case of meningitis. Children with bacteraemia were more likely to be febrile, feel hot, and have a history of fever than those with dysentery and skin infections. Fever combined with parental perception of fast breathing provided a more sensitive fever module for the detection of bacteraemia than the current IMCI module. CONCLUSIONS: In an area of low malaria prevalence, the IMCI guidelines provide antibiotics to the majority of children with bacterial infections, but improvements in the fever module are possible.

Bacterial Infections↗
PubMed2000

Responses to the major acrolein-derived deoxyguanosine adduct in Escherichia coli.

Acrolein, a reactive alpha,beta-unsaturated aldehyde found ubiquitously in the environment and formed endogenously in mammalian cells, reacts with DNA to form an exocyclic DNA adduct, 3H-8-hydroxy-3-(beta-D-2'-deoxyribofuranosyl)-5,6,7,8-tetrahydropyrido[3,2-a]purine-9-one (gamma-OH-PdG). The cellular processing and mutagenic potential of gamma-OH-PdG have been examined, using a site-specific approach in which a single adduct is embedded in double-strand plasmid DNA. Analysis of progeny plasmid reveals that this adduct is excised by nucleotide excision repair. The apparent level of inhibition of DNA synthesis is approximately 70% in Escherichia coli DeltarecA, uvrA. The block to DNA synthesis can be overcome partially by recA-dependent recombination repair. Targeted G --> T transversions were observed at a frequency of 7 x 10(-4)/translesion synthesis. Inactivation of polB, dinB, and umuD,C genes coding for "SOS" DNA polymerases did not affect significantly the efficiency or fidelity of translesion synthesis. In vitro primer extension experiments revealed that the Klenow fragment of polymerase I catalyzes error-prone synthesis, preferentially incorporating dAMP and dGMP opposite gamma-OH-PdG. We conclude from this study that DNA polymerase III catalyzes translesion synthesis across gamma-OH-PdG in an error-free manner. Nucleotide excision repair, recombination repair, and highly accurate translesion synthesis combine to protect E. coli from the potential genotoxicity of this DNA adduct.

Acrolein↗
PubMed2000

Induction of chromosomal instability in mouse hemopoietic cells by fetal irradiation.

Mice were exposed to 0.25-1.5Gy of gamma radiation on day 14 or 17 of gestation and chromosomal aberrations were scored in the bone marrow at 12 months of age. Irradiation had resulted in low peripheral blood counts, while some animals developed very high leukocyte counts. Exposed animals showed a significant dose dependent increase in the number of aberrant metaphases, compared to unexposed animals. Fragments and polyploidy were the major types of aberrations. Mice with abnormally high blood leukocyte counts showed a higher incidence of chromosomal aberrations, especially high levels of polyploidy than in animals with low blood counts. It is concluded that radiation induced genomic instability in the fetal hemopoietic cells of mouse is transmitted to postnatal and adult bone marrow which may lead to the development of hematological disorders, including malignancies.

Animals↗
PubMed2000

Mutagenesis induced by a single 1,N6-ethenodeoxyadenosine adduct in human cells.

To study the genotoxic properties of 1,N6-ethenodeoxyadenosine (epsilondA) in human cells, a novel site-specific mutagenesis approach was developed, in which a single DNA adduct was uniquely placed in either strand of a shuttle plasmid vector. The analysis of progeny plasmid derived from the modified strand shows that epsilondA, when incorporated into the position of the second A of 5'-CAA (codon 61 of the ras gene), is mutagenic in human cells, inducing A-->T, A-->G, and A-->C mutations. The efficient induction of A-->T transversions in experiments using modified double- and singlestranded DNA substrates supports the hypothesis that A:T-->T:A transversions in human and animal tumors induced by vinyl compounds reflect misinsertion of dAMP opposite this adduct. Mutagenic events were similar when the adduct was incorporated into either the leading or the lagging strand. EpsilondA was more mutagenic than 8-oxodeoxyguanosine, which induced targeted G-->T transversions in HeLa cells. In Escherichia coli, epsilondA did not significantly miscode (<0.27%) even in the presence of induced SOS functions.

Base Sequence↗
PubMed2000

The association between orthostatic hypotension and recurrent falls in nursing home residents.

PURPOSE: Orthostatic hypotension is common among the elderly, but its relation to falls is not certain. We determined whether orthostatic hypotension, including its timing and frequency, was associated with falls in elderly nursing home residents. SUBJECTS AND METHODS: We conducted a prospective study of 844 elderly (60 years of age and older), long-stay residents at 40 facilities that were part of a multistate nursing home chain. All subjects were able to maintain weight-bearing for at least 1 minute. Orthostatic hypotension was defined as a 20 mm Hg or greater decrease in systolic blood pressure from supine to standing, as measured after 1 or 3 minutes of standing on four occasions (before or after breakfast, or before or after lunch). The outcome was any subsequent fall during a mean of 1.2 years of follow-up. RESULTS: Orthostatic hypotension was present (at least on one measurement) in 50% of the subjects but was not associated with subsequent falls. However, among subjects with a history of previous falls in the past 6 months, those with orthostatic hypotension had an increased risk of recurrent falls [adjusted relative risk (RR) = 2.1; 95% confidence interval (CI), 1.4 to 3.1 ]. The risk of subsequent falls was greatest in previous fallers who had orthostatic hypotension at two or more measurements (RR = 2.6; 95% CI, 1.7 to 4.6). The association between orthostatic hypotension and recurrent falls was independent of measured demographic or clinical risk factors for falls. The timing of orthostatic hypotension (before or after meals) did not affect the risk of falls. CONCLUSIONS: Orthostatic hypotension is an independent risk factor for recurrent falls among elderly nursing home residents. Although the benefit of treating orthostatic hypotension will require further study, it may be prudent to identify high-risk residents and institute precautionary measures.

Accidental Falls↗
PubMed2000

An analysis of the safety of the single dose, two drug regimens used in programmes to eliminate lymphatic filariasis.

This review of the safety of the co-administration regimens to be used in programmes to eliminate lymphatic filariasis (albendazole + ivermectin or albendazole + diethylcarbamazine [DEC]) is based on 17 studies conducted in Sri Lanka, India, Haiti, Ghana, Tanzania, Kenya, Ecuador, the Philippines, Gabon, Papua New Guinea, and Bangladesh. The total data set comprises 90,635 subject exposures and includes individuals of all ages and both genders. Results are presented for hospital-based studies, laboratory studies, active surveillance of microfilaria-positive and microfilaria-negative individuals, and passive monitoring in both community-based studies and mass treatment programmes of individuals treated with albendazole (n = 1538), ivermectin (9822), DEC (576), albendazole + ivermectin (7470), albendazole + DEC (69,020), or placebo (1144). The most rigorous monitoring, which includes haematological and biochemical laboratory parameters pre- and post-treatment, provides no evidence that consistent changes are induced by any treatment; the majority of abnormalities appear to be sporadic, and the addition of albendazole to either ivermectin or DEC does not increase the frequency of abnormalities. Both DEC and ivermectin show, as expected, an adverse event profile compatible with the destruction of microfilariae. The addition of albendazole to either single-drug treatment regimen does not appear to increase the frequency or intensity of events seen with these microfilaricidal drugs when used alone. Direct observations indicated that the level of adverse events, both frequency and intensity, was correlated with the level of microfilaraemia. In non microfilaraemic individuals, who form 80-90% of the 'at risk' populations to be treated in most national public health programmes to eliminate lymphatic filariasis (LF), the event profile with the compounds alone or in combination does not differ significantly from that of placebo. Data on the use of ivermectin + albendazole in areas either of double infection (onchocerciasis and LF), or of loiais (with or without concurrent LF) are still inadequate and further studies are needed. Additional data are also recommended for populations infected with Brugia malayi, since most data thus far derive from populations infected with Wuchereria bancrofti.

Albendazole↗
PubMed2000

Evaluation of the cytogenetic damage and progenitor cell survival in foetal liver of mice exposed to gamma radiation during the early foetal period.

PURPOSE: To investigate the haemopoietic response to low dose gamma irradiation at the early foetal period when the liver is the major haemopoietic organ. MATERIALS AND METHODS: Pregnant Swiss albino mice were exposed to 0.1-1.5 Gy of gamma radiation on the 14th day of gestation. Twenty-four hours (15 day post conception (p.c.)) and 72 h (17 day p.c.) after exposure, the foetuses were dissected out, weighed, and liver weight and mean cellularity were determined. Cytogenetic damage in liver cells was assessed by chromosome aberration analysis and micronucleus (MN) count. The haemopoietic progenitor cell survival at 24 h and 72 h after exposure was measured by exogenous spleen colony assay on day 8 (CFU-S8) and day 12 (CFU-S12) after intravenous injection of the foetal liver cells into adult bone marrow-ablated recipient mice. RESULTS: The foetal body weight at 24 h after exposure showed a significant reduction at doses of 0.5 Gy and above, while the 72 h body weight was significantly lower than control from 0.3 Gy onwards. Liver weight showed a similar reduction for doses from 0.25 to 1.5 Gy at both the post-irradiation observation times. However, when liver weight/body weight ratios were compared, there was no significant difference between the irradiated and control values. Total liver cellularity at 24 h and 72 h after exposure showed a dose-dependent decrease, with significant depletion from control at 0.25 Gy and above. When donor cells were taken at 24 h after exposure (15 day p.c.) the CFU-S8 showed a significant decrease only at 1.0 and 1.5 Gy, while the CFU-S12 suffered such a depletion at 0.25-1.5 Gy. For donor cells recovered at 72 h after exposure, both CFU-S8 and CFU-S12 decreased linear-quadratically with radiation dose and were significantly lower than control at 0.25 Gy. A significant increase in the percent aberrant metaphases and micronucleus counts was seen at 0.1 Gy and 0.15 Gy, respectively, and increased linear-quadratically with radiation dose. CONCLUSIONS: The results demonstrate that the liver, which is the major haemopoietic organ at the early foetal period, is highly sensitive to radiation damage from maternal irradiation. At low doses, the lethal effect on the haemopoietic stem cells appears to develop more slowly than at higher doses.

Animals↗
PubMed2000

Induction of solid tumours in the Swiss albino mouse by low-dose foetal irradiation.

PURPOSE: To study the tumourigenic effect of prenatal low-dose gamma-irradiation in the mouse. METHODS AND MATERIALS: Pregnant Swiss albino mice were exposed to 0.1-1.5 Gy gamma-radiation on days 14 or 17 of gestation. The F1 offspring were observed up to 18 months of age. All the mice were killed at 18 months and the incidence of tumours in different organs was recorded. RESULTS: Exposure to doses from 0.1 to 1.5 Gy on days 14 or 17 of gestation produced a linear-quadratic dose-dependent increase in tumour incidence in adult F1 mice. The main organs affected were the ovary, uterus, liver and spleen. The highest incidence was observed in the ovaries, which was significantly higher than spontaneous incidence, even at 0.25 Gy. In other organs the tumour incidence was not significant compared with controls at doses < 0.5-1.0 Gy. Tumours in the ovary and uterus developed at an earlier age than in the liver and spleen. CONCLUSIONS: Exposure to gamma-radiation < 1.0 Gy at the foetal period (days 14 or 17 of gestation) can cause induction of tumours in the Swiss albino mouse. The carcinogenic effect, particularly on the ovary among the female mouse, is detectable after low-dose foetal irradiation.

Animals↗
PubMed2000

Effect of irradiation at the early fetal stage on adult brain function in the mouse: locomotor activity.

PURPOSE: To study long-term changes in the adult locomotor activity of mice after exposure to gamma radiation at the early fetal stage of development. MATERIALS AND METHODS: Pregnant Swiss albino mice were exposed locally on the abdominal area to a single dose of 0.25-1.5 Gy of 60Co gamma radiation at the dose rate of 1 Gy/min. When the F1 offspring were 6 months old, their locomotor and exploratory behaviour was assessed by the open-field and dark/bright arena tests. Animals were again subjected to the dark/bright arena test at 12 and 18 months of age in order to study the persistence of the effects. RESULTS: Irradiation produced a noticeable disturbance in the normal behaviour pattern of the mice. There was a significant dose-dependent decrease in the open-field activity of 6-month-old mice. In the dark/bright arena test, the time spent and lines crossed in the dark area showed a significant decrease, while their activities in the brightly lit area increased significantly, indicating a reduced aversion to bright light. These effects were evident even at a dose of 0.3 Gy and increased linearly with dose. The significant behavioural changes persisted at 12 months, but at 18 months the difference in the time spent and lines crossed in the dark and bright areas were not significantly different from sham-irradiated control values below 0.5 Gy. CONCLUSIONS: These results show that day 14 of gestation in Swiss albino mice is a time of high risk for inducing long-term changes in the adult locomotor function by gamma-radiation doses below 1 Gy. Using a range of radiation doses and different observation times we have demonstrated that the effect increases linearly with dose, but there appears to be a threshold of 0.3-0.5 Gy for producing significant persistent changes in the adult ambulatory activity.

Age Factors↗
PubMed2000

Removal effects of the Nd:YAG laser and Carisolv on carious dentin.

OBJECTIVE: The purpose of this study was to investigate the removal effect of the Nd:YAG laser irradiation and Carisolv on carious dentin. BACKGROUND DATA: Many previous studies have reported several simple and alternative techniques, such as lasers and chemicals, for caries removal. METHODS: Carisolv was applied on the surface of 20 extracted human anterior and molar teeth for 1 min and then the Nd:YAG laser was irradiated with a continuous water spray for another 1 min. The energy densities were varied from 2 to 6W with a repetition rate of 20 pps. As caries removal progressed, the cavity was carefully assessed by DIAGNOdent. Each lesion was photographed before and after treatment, and the treated cavity was observed microscopically using a stereoscope and with scanning electron microscope (SEM). Thermal change at the time of laser irradiation was measured by thermovision. RESULTS: Our results revealed that application of Carisolv followed by Nd:YAG laser irradiation at 4-6W pulse energy effectively removed dentin caries. The total procedure was usually repeated once or twice for complete caries removal. From the SEM study, it was found that the cavity surface treated with the laser revealed various patterns of microirregularity, often accompanied by microfissure propagation. There was also no smear layer. CONCLUSIONS: It was revealed that Nd:YAG laser and Carisolv could provide an alternative technique for caries removal instead of the conventional mechanical drilling and cutting.

Dental Caries↗
PubMed2000

Removal of gingival melanin pigmentation with the semiconductor diode laser: a case report.

OBJECTIVE: This investigation was performed to evaluate the possibility of the removal of canine gingival melanin pigmentation with the semiconductor diode (SCD) laser in vivo. SUMMARY BACKGROUND DATA: Recently, a semiconductor laser, which can ablate soft tissue, has been developed. It is already used in dentistry as well as in medicine. METHODS: The SCD laser was irradiated on the pigmented area of canine gingival surface with the irradiation output of 3W. The effect of the SCD laser irradiation was evaluated at the two intervals: immediately after irradiation and at 3 weeks following irradiation. In addition, histological examination was performed before irradiation and at the same intervals from the biopsies (4 microm) of unlased and lased areas. RESULTS: The SCD laser was effective in removing melanin pigmentation. In histological examination, neither inflammatory cell nor any tissue damage was observed with hematoxylin-eosin staining. At 3 weeks, there was a continuous healing process with the proliferation of squamous epithelial cells. CONCLUSIONS: SCD laser irradiation can be considered an alternative procedure for removal of melanin pigmentation.

Animals↗
PubMed2000

Caries-preventive effect of Er:YAG laser irradiation with or without water mist.

OBJECTIVE: This investigation was performed to evaluate the effect of Er:YAG laser irradiation on the acquired acid resistance of sound dental hard tissues to artificial caries formation by spectrophotometry, and the ultrastructure of lased areas was investigated by scanning electron microscopy (SEM) in vitro. BACKGROUND DATA: Although an Er:YAG laser has shown the most promise for hard tissue ablation, there have not been any dissolution studies to determine if this laser is suitable for caries preventive treatments. METHODS: An Er:YAG laser was used to irradiate the enamel and dentin samples from 20 extracted human molars at 400 mJ pulse energy with or without water mist. Samples were subjected to 2 microL of 0.1 M lactic acid solution (pH 4.8) for 24 hours at 36 degrees C. The parts per million (ppm) of calcium ion (Ca2+) dissolved in each solution was determined by atomic absorption spectrophotometry and the morphological changes were investigated by SEM. RESULTS: The lowest mean Ca2+ ppm was recorded in the samples irradiated without water mist, in those by irradiated with water mist, and in the unlased samples. SEM observation showed that the lased areas had melted and seemed to be thermally degenerated when irradiated without water mist. After acid demineralization, the thermally degenerated enamel or dentin surfaces were almost unchanged. CONCLUSIONS: The results of this study suggest that Er:YAG laser irradition with and without water mist appears to be more effective for caries prevention.

Dental Caries↗
PubMed2000

An optimized forward-planning technique for intensity modulated radiation therapy.

Intensity modulated radiation therapy (IMRT) has stirred considerable excitement in the radiation oncology community. Its objective is to make the dose conform to the tumor and spare other organs. Instead of resorting to the rather complex inverse-planning, the technique described here is an extension of the conventional treatment planning technique. The beam orientation and wedge angles are chosen in the conventional rule-based manner. However, within each conformal beam's eye view (BEV) field including margin, a number of sub-field openings are added. The smaller field openings are designed to irradiate the tumor, while sparing the normal tissue of the organs at risk (OARs) that intrude into the target region in the BEV. As the number of intrusions into the target BEV increases, the number of sub-fields for each beam increases. The Cimmino simultaneous projection method was employed to obtain the optimized weighting for each field of each beam. In cases where the dose constraints for the tumor and for the OARs are reasonable, it is possible to obtain a plan with a fairly small number of beams that satisfies the specified dose objectives. This is illustrated for the treatment of prostate cancer, where the rectum creates a concavity in the planning target volume. An advantage of this technique is that the quality assurance for the delivery of these plans does not require extensive special efforts.

Algorithms↗