Radiobiological Optimization in Lung Stereotactic Body Radiation Therapy: Are We Ready to Apply Radiobiological Models?

Lung tumors are often associated with a poor prognosis although different schedules and treatment modalities have been extensively tested in the clinical practice. The complexity of this disease and the use of combined therapeutic approaches have been investigated and the use of high dose-rates is emerging as effective strategy. Technological improvements of clinical linear accelerators allow combining high dose-rate and a more conformal dose delivery with accurate imaging modalities pre- and during therapy. This paper aims at reporting the state of the art and future direction in the use of radiobiological models and radiobiological-based optimizations in the clinical practice for the treatment of lung cancer. To address this issue, a search was carried out on PubMed database to identify potential papers reporting tumor control probability and normal tissue complication probability for lung tumors. Full articles were retrieved when the abstract was considered relevant, and only papers published in English language were considered. The bibliographies of retrieved papers were also searched and relevant articles included. At the state of the art, dose-response relationships have been reported in literature for local tumor control and survival in stage III non-small cell lung cancer. Due to the lack of published radiobiological models for SBRT, several authors used dose constraints and models derived for conventional fractionation schemes. Recently, several radiobiological models and parameters for SBRT have been published and could be used in prospective trials although external validations are recommended to improve the robustness of model predictive capability. Moreover, radiobiological-based functions have been used within treatment planning systems for plan optimization but the advantages of using this strategy in the clinical practice are still under discussion. Future research should be directed toward combined regimens, in order to potentially improve both local tumor control and survival. Indeed, accurate knowledge of the relevant parameters describing tumor biology and normal tissue response is mandatory to correctly address this issue. In this context, the role of medical physicists and the AAPM in the development of radiobiological models is crucial for the progress of developing specific tool for radiobiological-based optimization treatment planning.

Postpartum period: three distinct but continuous phases.

Postpartum period is distinct in three phases. The third phase is the delayed postpartum period, which can last up to 6 months. Some changes to the genitourinary system are much longer in resolving, and some may never fully revert to the prepregnant state. A burgeoning volume of literature on pelvic floor support implicates childbirth as the initiation of a whole host of conditions including stress urinary incontinence, incontinence of flatus or feces, uterine prolapse, cystocele, and rectocele. The duration and severity of these conditions affect many variables, including the patient's intrinsic collagen support, the size of the infant, the route of delivery, and the degree of perineal trauma occurring either naturally (lacerations) or iatrogenically (episiotomy).

Putative protective effects of cesarean section on pelvic floor disorders.

Pregnancy can affect the lower genitourinary tract through physiologic changes, or traumatic injury tissue stretching and tearing, besides neurologic and vascular compression and compromise, and muscle strain are inevitable during childbirth.The levator ani complex of the pubococcygeus, puborectalis, and iliococcygeus muscles must allow passage of the fetus. The perineal body and external anal sphincter may become injured, with or without episiotomy, but sometimes as a necessary maneuver to allow passage of the fetal head or shoulders. The traumatic insults may lead to permanent damage on pelvic floor and subsequent urinary or anal incontinence.In this article we aim to review the literature regarding the impact of pregnancy or childbirth on pelvic floor changes.

Antepartum haemorrhage.

OBJECTIVE: Antepartum haemorrhage (APH) defined as bleeding from the genital tract in the second half of pregnancy, remains a major cause of perinatal mortality and maternal morbidity in the developed world. RESULTS: In approximately half of all women presenting with APH, a diagnosis of placental abruption or placenta praevia will be made; no firm diagnosis will be made in the other half even after investigations. CONCLUSION: In cases presenting with APH, the evaluation consists of history, clinical signs and symptoms and once the mother is stabilized, a speculum examination and an ultrasound scan.A revision of the literature was mode only larger prospective tials or case-control study were taken into account.

Obesity and fetal-maternal outcomes.

In women Obesity has a significant impact on every aspect of female reproductive life both in terms of infertility and early pregnancy complications. It is linked to a number of adverse obstetric outcomes as well as increased maternal and neonatal morbidity and mortality. These complications include miscarriage, congenital abnormalities, pre-eclampsia, gestational diabetes mellitus, iatrogenic preterm delivery, post-dates pregangy with increased rates of induction of labour, caesarian section and complications during and following operative procedures, post-partum haemorrhage, shoulder dystocia, infection, venous thromboembolism and increased hospital day. It is important to consider obese pregnant women as a high risk group with a linear increase in risk of complications associated with their degree of obesity.

Uterine artery Doppler flow studies in obstetric practice.

In women who develop preeclampsia there is a pathological increase in placental vascular resistance should be detectable by abnormal Dopplerf low studies of the maternal uterine vessels. In women considered at low risk with abnormal early pregnancy uterine artery Doppler studies are needed. Until such time as these are available, routine uterine artery Doppler screening of women considered at low risk is not recommended. Uterine artery Doppler screening of high-risk women appears to identify those at substantially increased risk for adverse pregnancy outcomes and interventions that might improve clinical outcomes.Abnormal testing in these women could potentially lead to increased surveillance and interventions that might improve clinical outcomes.

Post partum pelvic floor changes.

Pelvic-perineal dysfunctions, are the most common diseases in women after pregnancy. Urinary incontinence and genital prolapsy, often associated, are the most important consequences of childbirth and are determined by specific alterations in the structure of neurological and musculo-fascial pelvic support.Causation is difficult to prove because symptom occur remote from delivery.Furthermore it is unclear whether changes are secondary to the method of childbirth or to the pregnancy itself.This controversy fuels the debate about whether or not women should be offered the choice of elective caesarean delivery to avoid the development of subsequent pelvic floor disfunction.But it has been demonstrated that pregnancy itself, by means of mechanical changes of pelvic statics and changes in hormones, can be a significant risk factor for these diseases. Especially is the first child to be decisive for the stability of the pelvic floor.During pregnancy, the progressive increase in volume of the uterus subject perineal structures to a major overload. During delivery, the parties present and passes through the urogenital hiatus leading to growing pressure on the tissues causing the stretching of the pelvic floor with possible muscle damage, connective tissue and / or nervous.In this article we aim to describe genitourinary post partum changes with particular attention to the impact of pregnancy or childbirth on these changes.

Fetal cystic lymphangioma of the neck: a case report.

OBJECTIVE: A case of fetal neck lymphangioma is reported METHODS: A 34-year-old primigravida presented with a fetus at 21+5 weeks' gestation with a neckl cystic mass. RESULTS: Diagnosis of neck lymphangioma was made; the couple opted for termination of pregnancy a 22 weeks; they refused fetal autopsy. CONCLUSION: Counseling in case of neck lynphangioma is still difficult. Prognosis in guarded as many patients decide for interruption of pregnancy.

Echotomography of craniosynostosis: review of literature.

Ultrasound examination of the foetal cranium can diagnose fetal cranial defects and abnormal skull shape and it's aim is to detect in prenatal age most various abnormalities of the skull, brain and foetal face. The changes of each of these components frequently determine the growth of the other two.The abnormalities of the foetal head frequently appear and can associate serious pathological sceneries of high foetal and perinatal morbidity and mortality.Anomalies of the head have been observed using ultrasound study during the early second trimester. To establish diagnosis and long term prognosis is particularly important and helpful correct detection of the nature of the malformation.

Obstetric management in Rh alloimmunizated pregnancy.

Rh alloimmunization occurs when maternal immune system is sensitized to D(Rh) erythrocyte surface antigens.The most common causes of maternal Rh alloimmunisation are blood transfusion and antepartum or intrapartum fetomaternal hemorrhage (abdominal trauma, abortion, ectopic pregnancy, invasive obstetric procedures, placental abruption, external cephalic version).The risk of alloimmunization is affected by several factors, including the degree of fetomaternal hemorrhage and maternal immune respons.Although the introduction of anti D prophylaxis reduced dramatically the rate of alloimmunization in susceptible women, his prevention is not universal and about 0.3% of susceptible women still become Rh D alloimmunized.The aim of this article is to review the management of the Rh alloimmunizated pregnant.

Abnormal skull findings in neural tube defects.

The human neural tube develops and closes during the third and fourth week after conception and is normally completed by 28 days post-conception. Malformations, knows as neural tube defects, occure, when the normal closure process fails. Several clinical types of neural tube defects are recognized, anencefaly and spina bifida being the most common. Such malformations are generally associated with cranial abnormlities.