Uterine Dose Research Articles

Assessment of foetal dose and occupational exposure for pregnant workers in nuclear medicine using the Taiwanese pregnancy phantom.

For pregnant workers in nuclear medicine, radiation doses can pose a risk to their foetus. However, foetal radiation doses cannot be measured directly. In this study, a method of estimating foetal radiation doses was developed through simulations and measurements of phantoms of pregnant women in the three trimesters. The uterus and abdominal surface doses for monoenergetic photons (137Cs) and medical diagnostic X-rays were measured, and uterine dose conversion coefficients (UDCCs) were calculated. The accuracy of the UDCC estimates were validated for measurements from thermoluminescent dosemeter (TLD) chips and TLD badges on the abdomen or chest. The foetal effective dose could be estimated using TLD chips and TLD badges on the abdomen or chest, or through literature estimation method. The proposed method can be used to easily and accurately estimate foetal effective doses from chest-worn TLD badges, ensuring accurate estimation in the early stage of pregnancy when a worker may not yet be wearing an abdominal badge. A flowchart for applying the UDCC method to approximate a foetal dose is also provided to ensure that total doses remain below the maximum of 1mSv recommended in the International Commission on Radiological Protection 103 guidelines.

Neurocognitive Function in Aged Survivors Exposed to Atomic Bomb Radiation In Utero: The Radiation Effects Research Foundation Adult Health Study.

Although some adverse effects on neurocognitive function have been reported in children and adolescents irradiated prenatally during the atomic bombings and the Chernobyl nuclear accident, little information is available for effects on the elderly. Here we evaluate the effects of prenatal exposure to atomic bomb radiation on subjective neurocognitive function in aged survivors. To evaluate neurocognitive impairment, we mailed the Neurocognitive Questionnaire (NCQ), a self-administered scale, to prenatally exposed survivors, including clinic visitors and non-visitors at the time of the 2011 and 2013 Adult Health Study (AHS) examinations. We received replies from 444 individuals (mean age, 66.9 ± 0.6 years). After adjusting for sex, city, and educational background, we found no significant effects of radiation, clinic visit, or interaction between radiation and clinic visit on the scores of the 4 NCQ factors of metacognition, emotional regulation, motivation/organization, and processing speed. Even in analyses considering gestational age at the time of the bombings, none of the 4 NCQ factor scores was related to maternal uterine dose. There remains the limitation that this study consisted of healthy survivors, but we found no significant radiation effect on late-life cognition in people prenatally exposed to atomic bomb radiation.

Effects of Radiation Therapy on the Female Reproductive Tract in Childhood Cancer Survivors: A PENTEC Comprehensive Review

The PENTEC (Pediatric Normal Tissue Effects in the Clinic) task force aimed to quantify effects of radiation therapy (RT) dose to the female reproductive organs after treatment for childhood cancer. Relevant studies published 1970 to 2017 were identified systematically through PubMed, Medline, and Cochrane databases with additional articles before 2021 identified by the group. Two large studies reported sufficient data to allow modeling of acute ovarian failure (AOF; loss of function ≤5 year from diagnosis) and premature ovarian insufficiency (POI; loss of function at attained age <40 years) based on maximum dose to least affected ovary. Although normal tissue complication probability modeling was not feasible for the uterus due to limited data, the relationship between ultrasound-measured uterine volume and estimated amount of RT was plotted. Limited data regarding vaginal toxicity were available. The risk of AOF increases with RT dose to least affected ovary, alkylating agent cumulative dose (cyclophosphamide equivalent dose [CED] in g/m2), age at RT, and stem cell transplantation: Two Gy to the least affected ovary resulted in AOF risk of 1% to 5% (CED = 0, risk increasing with age), 4% to 7% (CED = 10 g/m2, risk increasing with age), and 6% to 13% (CED = 30 g/m2, risk increasing with age). For patients aged 1 and 20 years at time of RT, AOF risk was ≥50% at doses of 24 Gy and 20 Gy with no alkylating chemotherapy, 22.5 Gy and 17 Gy with intermediate alkylator dose (10 g/m2), and 17 Gy and 13 Gy with high alkylator dose (30 g/m2). Risk of POI increases with survivor (attained) age (rather than age at time of RT), radiation dose to least affected ovary, and alkylator dose. Data review suggested that higher radiation doses to the uterus are associated with uterine toxicity, with uterine size considerably restricted after 12 Gy. Vaginal radiation in children is associated with high toxicity risk, although dose-volume data are not available for quantification. Risk of AOF increases with age at RT, CED exposure, and RT dose; risk of POI likewise increases with RT dose, CED exposure, and survivor age. Both AOF and POI are expected to affect fertility and estrogen production. Data suggest that RT uterine dose >12 Gy may be associated with uterine size restriction. Adult literature suggests that maintaining vaginal dose <5 Gy may limit toxicity. Treatment of life-threatening malignancy remains a priority over reproductive preservation; however, when possible, radiation and surgical techniques should be considered to minimize dose to least affected ovary, uterus, and vagina. Survivors should receive endocrine and gynecologic support; those desiring pregnancy should be counseled early to maximize reproductive options.

Reconsidering pregnancy screening policies for minors: patient-specific estimate of fetus and effective dose for potentially pregnant minors undergoing optimized dose CT of the pelvis.

Only verbal pregnancy screening is recommended for post-menarcheal females undergoing pelvic radiographs. In contrast, usually, a urine/serum pregnancy test for pelvic computed tomographic (CT) exams is required out of concern for higher radiation exposure. To estimate patient-specific fetus absorbed dose to a potentially pregnant minor from an optimized dose CT of the pelvis for femoral version and surgical planning and provide evidence that such examinations of the pelvis can be performed with only verbal pregnancy screening. A retrospective study was performed on 102 female patients between 12-18years of age (15.4 ± 2.1years) who underwent optimized dose CT of the pelvis for orthopedic evaluation of femoral version and surgical planning. Optimized CT exams were performed with weight-adjusted kVp and tube current modulation. Patient-specific dose from the optimized dose CT was calculated using the National Cancer Institute Dosimetry System for CT (NCICT) database by matching each patient to a phantom from the NCI non-reference phantom library based on patient sex, weight, and height. The calculated absorbed uterus dose was used as a surrogate for the fetus dose. Furthermore, patient-specific organ doses were used to estimate the effective dose.The strengths of the linear relationships between the dose metrics and patient characteristics were assessed using Pearson correlation coefficients throughlinear regression. The mean patient-specific effective dose for an optimized dose CT of the pelvis was 0.54 ± 0.20mSv (range: 0.15-1.22mSv). The mean estimated absorbed uterine dose was 1.57 ± 0.67mGy (range: 0.42-4.81mGy). Both effective dose and estimated uterine dose correlated poorly with patient physical characteristics (R = -0.26; 95% CI: [-0.43, -0.007] for age, R = 0.03; 95% CI: [-0.17, 0.22] for weight) but correlated strongly (R = 0.79, 95% CI: [0.7, 0.85]) with CTDIvol. The estimated fetus dose in case of pregnancy was significantly lower than 20mGy for urine/serum pregnancy screening, suggesting that the pregnancy screening protocols in minors undergoing optimized dose CT require reassessment and may be safely performed by verbal attestation only.

UTERINE DOSE CONVERSION COEFFICIENTS FOR EXTERNAL PHOTONS FOR THE TAIWANESE PREGNANT WOMEN.

The Oak Ridge National Laboratory (ORNL) phantoms based on data of Caucasians have been widely used for fetal dosimetry. However, there are differences in body size during pregnancy among Taiwanese and Caucasians. In this study, the uterine dose conversion coefficients (DCCs) of Taiwanese pregnant women were evaluated to facilitate the use of it to estimate the possible uterine dose (usually regarded as fetal dose) of pregnant Taiwanese women during radiation practice or medical exposures. The uterine DCCs in this study were calculated based on the established Taiwanese pregnancy voxel phantoms, and were compared with the uterine DCCs of the International Commission on Radiological Protection. The applicability of evaluating uterine DCCs with different phantoms was also discussed. Results showed that if the ORNL phantoms are used to evaluate the uterine dose of Taiwanese pregnant women, the uterine dose may be underestimated. This study provides the uterine DCCs assessed with the Taiwanese pregnancy phantoms for future dose assessment of Taiwanese.

Assessment of the uterine dose in digital mammography and digital breast tomosynthesis

IntroductionDigital Mammography (DM-2D) and more recently Digital Breast Tomosynthesis (DBT), are two of the most effective imaging modalities for breast cancer detection, often used in screening programmes. It may happen that exams using these two imaging modalities are inadvertently performed to pregnant women. The objective of this study is to assess the dose in the uterus due to DM-2D and DBT exams, according to two main irradiation scenarios: in the 1st scenario the exposure parameters were pre-selected directly by the imaging system, while in the 2nd scenario, the maximum exposure parameters were chosen. MethodsThe mammography equipment used was a Siemens Mammomat Inspiration. A physical anthropomorphic phantom, PMMA plates (simulating a breast thickness of 6 cm) and thermoluminescent dosimeters (TLDs) were used to measure entrance air kerma values on the phantom's breast and abdomen in order to successively estimate the mean glandular dose (MGD) and the dose in the uterus. For the two irradiation scenarios chosen, two-breast imaging modalities were selected: 1) DBT in Cranio-Caudal (CC) view (with 28 kV and 160 mAs as exposure parameters), 2) DBT and DM in Medio Lateral-Oblique (MLO) and CC views (with 34 kV and 250 mAs as exposure parameters). ResultsIn the 1st scenario, the TLD measurements did not detect significant dose values in the abdomen whereas the MGD estimated using the D.R. Dance model was in close agreement with data available in the literature. In the 2nd scenario, there was no significant difference in MGD estimation between the different views, whereas the air kerma values in the abdomen (in DBT mode, CC and MLO) were 0.049 mGy and 0.004 mGy respectively. In CC DM-2D mode the abdomen air kerma value was 0.026 mGy, with no significant detected value in MLO view. ConclusionsFor the dose in the uterus, the obtained values seem to indicate that DM-2D and DBT examinations inadvertently performed during pregnancy do not pose a significant radiological risk, even considering the case of overexposure in both breasts. Implications for practiceThe accurate knowledge of the doses in DM-2D and DBT will contribute to raise the awareness among medical practitioners involved in breast imaging empowering them to provide accurate information about dose levels in the uterus, improving their radiation risk communication skills and consequently helping to reduce the anxiety of pregnant women undergoing this type of examinations.

Mortality among individuals exposed to atomic bomb radiation in utero: 1950\u20132012

We examined the mortality risks among 2463 individuals who were exposed in utero to atomic bomb radiation in Hiroshima or Nagasaki in August 1945 and were followed from October 1950 through 2012. Individual estimates of mother’s weighted absorbed uterine dose (DS02R1) were used. Poisson regression method was used to estimate the radiation-associated excess relative risk per Gy (ERR/Gy) and 95% confidence intervals (CI) for cause-specific mortality. Head size, birth weight, and parents’ survival status were evaluated as potential mediators of radiation effect. There were 339 deaths (216 males and 123 females) including deaths from solid cancer (n = 137), lymphohematopoietic cancer (n = 8), noncancer disease (n = 134), external cause (n = 56), and unknown cause (n = 4). Among males, the unadjusted ERR/Gy (95% CI) was increased for noncancer disease mortality (1.22, 0.10–3.14), but not for solid cancer mortality (− 0.18, < − 0.77–0.95); the unadjusted ERR/Gy for external cause mortality was not statistically significant (0.28, < − 0.60–2.36). Among females, the unadjusted ERRs/Gy were increased for solid cancer (2.24, 0.44–5.58), noncancer (2.86, 0.56–7.64), and external cause mortality (2.57, 0.20–9.19). The ERRs/Gy adjusted for potential mediators did not change appreciably for solid cancer mortality, but decreased notably for noncancer mortality (0.39, < − 0.43–1.91 for males; 1.48, − 0.046–4.55 for females) and external cause mortality (0.10, < − 0.57–1.96 for males; 1.38, < − 0.46–5.95 for females). In conclusion, antenatal radiation exposure is a consistent risk factor for increased solid cancer mortality among females, but not among males. The effect of exposure to atomic bomb radiation on noncancer disease and external cause mortality among individuals exposed in utero was mediated through small head size, low birth weight, and parental loss.

Predictors of Premature Ovarian Failure (POF) in Young Women with Locally Advanced Rectal Cancer (LARC) Treated with Pelvic Radiation Therapy (RT)

Pelvic RT is standard of care for patients with LARC. POF in pre-menopausal women is a possible side effect of this treatment. The predicted rise in rectal cancer in 2030 is 124% for patients 20-34 and 6% for patients 35-49 yrs. The purpose of our study was to evaluate the clinical and dosimetric predictors of POF in women younger than 50 years, treated with pelvic RT for LARC, including those who underwent ovarian transposition (OT). We retrospectively reviewed the medical records of women younger than 50 treated with pelvic RT for LARC at our institution between 2001-2019. Clinical [date of last menstrual period], and hormonal data [FSH, LH, and estradiol levels] were used to determine ovarian function. The ovaries and uterine body/fundus were contoured on the simulation scans by a single dosimetrist, and dose volume histograms were generated. Association of factors with POF was evaluated using Cox regression and optimal dosimetry cut-offs were based on maximum log rank statistic. The study identified 76 women who were premenopausal at time of RT. Median age at RT was 43 years [range 20-49]. Fertility preservation [FP] referral was done for 53% of the women, and 34% underwent OT. Neoadjuvant, concurrent and adjuvant chemotherapy was administered in 74%, 91%, and 34% of women respectively. Median RT dose was 50Gy in 25 fractions. Intensity modulated RT was used in 61% and 39% had 3D-RT. Only 26% had preservation of ovarian function, all in the OT group, and 1 woman carried a high-risk pregnancy 15 years after end of treatments, with premature birth at 25 weeks. Ovarian function was preserved in 77% of women who underwent OT. Median time from start of RT to POF was 17 days [7-54 days], and those patients did not resume menses >1 year after competing treatments. Compared to patients who underwent OT, those who haven’t had significantly higher means of ovarian doses (p<0.001): maximum dose [Right (R): 47.1 vs. 2.7 Gy, Left (L): 46.9 vs. 5.8 Gy], minimum dose [R: 40.6 vs. 0.5 Gy, L: 30.6 vs. 0.8 Gy], and mean dose [R: 45.1 vs. 1.1 Gy, L: 43.7 vs. 1.5 Gy]. Uterine doses were similar [medians >40Gy in both groups]. On univariable analysis, OT (HR: 0.05) and age at RT (HR: 1.18) were significantly associated with POF (p <0.001). At the optimal threshold for ovarian doses, patients with mean R ovarian dose >5.322 Gy had L>4.90 and bilateral >4.12 Gy and were significantly associated with higher risk of POF (HR 16.9, p<.001). However, on multivariable analysis, only OT remained independently associated with risk of POF. RT modality and chemotherapy had no significant effect. OT significantly reduced the risk of POF in our cohort, and should be considered in premenopausal women undergoing pelvic RT. Even with OT, ovarian doses approached 6Gy in some patients. We are currently investigating the role of protons therapy in further sparing the ovaries and uterus.

Mesure de la dose délivrée hors champ à l’utérus lors d’un traitement ORL par protons

The decision to irradiate during pregnancy is based on a risk benefit compromise of two kinds: maternal risk and fetal risk. The aim of this work is to determine the foetal risk, and uterine dose measurement in proton therapy. Foetal exposure during treatment is linked to two sources: the treatment phase, and the repositioning phase. An Alderson-Rando anthropomorphic ghost (170cm, 74kg) was positioned on the table in the treatment position. A tissue-equivalent proportional counter (TEPC), adapted to the analysis of complex radiation fields (neutron and photonics), was used to determine the irradiation related to the treatment phase. An AT1123 radiation survey meter was used to measure photons generated by X-ray radiation. I dosimetry was proposed using radio-photoluminescent dosimeters, allowing for a daily check of the dose received in the uterus. The treatment phase produces higher uterine doses than the positioning phase, but these remain very low. The equivalent dose received in the uterus for the entire treatment is estimated at 840 μSv. Using a methodology for measuring the out-of-field dose with pencil beam scanning proton therapy, the foetal dose in the first trimester was well below the acceptance dose of 100 mGy determined by the International Commission on Radiological Protection.

Effect of Dayak Onion (Eleutherine bulbosa (Mill.) Urb) on Uterine wall and Lipid Profiles of Ovariectomized Rat

Menopause is a physiologic condition, in which women no longer experience menstruation. Decreased estrogen during and after menopause causes structural, physiological and biochemical changes that alter the health of women in general, both in organs and non-reproductive organs. Dayak onion contains eleuterinol, an naphtoqunone derivative that can be as SERM. Therefore, we evaluated the effects of dayak onions on lipid profiles and uterine wall. This study used female white rats of Sprague-Dawley. All groups, except the sham group, is ovariectomized to obtain the conditions of hypoestrogen. Rats were divided into 6 groups. SHAM (CMC Na 0,5%), OVX (CMC Na 0,5%), TAM (tamoxifen), DOE dose 1 (dayak onion extract 8 mg/200), DOE dose 2 (dayak onion extract 12 mg/200 g) and DOE dose 3 (dayak onion extract 18 mg/200 g). Mouse model of ovariectomy given 3 doses of extract, from giving each extract it was seen that the weight of uterine DOE dose 1, DOE dose 2 and DOE dose 3 respectively 55,24, 53,38 and 61,85 mg had lower uterine weight when compared with Positive control given tamoxifen 72.2 mg. The effects of onion on uterine weight reduction are greater than that of tamoxifen on the animal model menopause.

Fetal radiation dose in three common CT examinations during pregnancy – Monte Carlo study

PurposeTo determine fetal doses in different stages of pregnancy in three common computed tomography (CT) examinations: pulmonary CT angiography, abdomino-pelvic and trauma scan with Monte Carlo (MC) simulations. MethodsAn adult female anthropomorphic phantom was scanned with a 64-slice CT using pulmonary angiography, abdomino-pelvic and trauma CT scan protocols. Three different sized gelatin boluses placed on the phantom’s abdomen simulated different stages of pregnancy. Intrauterine dose was used as a surrogate to a dose absorbed to the fetus. MC simulations were performed to estimate uterine doses. The simulation dose levels were calibrated with volumetric CT dose index (CTDIvol) measurements and MC simulations in a cylindrical CTDI body phantom and compared with ten point doses measured with metal-oxide-semiconductor field-effect-transistor dosimeters. Intrauterine volumes and uterine walls were segmented and the respective dose volume histograms were calculated. ResultsThe mean intrauterine doses in different stages of pregnancy varied from 0.04 to 1.04mGy, from 4.8 to 5.8mGy, and from 9.8 to 12.6mGy in the CT scans for pulmonary angiography, abdomino-pelvic and trauma CT scans, respectively. MC simulations showed good correlation with the MOSFET measurement at the measured locations. ConclusionsThe three studied examinations provided highly varying fetal doses increasing from sub-mGy level in pulmonary CT angiography to notably higher levels in abdomino-pelvic and trauma scans where the fetus is in the primary exposure range. Volumetric dose distribution offered by MC simulations in an appropriate anthropomorphic phantom provides a comprehensive dose assessment when applied in adjunct to point-dose measurements.

Predelivery uterine arteries embolization in patients affected by placental implant anomalies.

The aim of this study is to report on a single center experience of managing patients affected by placenta previa major and/or accretism by embolizing uterine arteries immediately before the cesarean delivery to reduce blood loss and secondary the rate of hysterectomies. Sixty-nine patients have been prospectively enrolled. Inclusion criteria were radiological diagnosis of placenta anomalies and risk factors for peri/postpartum hemorrhage. The delivery was electively scheduled between the 35th week and the 36th week of pregnancy. The embolization procedure was performed in the gynecological operating room with a mobile C-arm by injecting calibrated microparticles 500-700μm. A contrast-enhanced MRI was acquired in a subgroup of 10 patients 6months after the delivery to evaluate the uterine wall status. Hysterectomy had been performed in 43.5%; 52.2% did not require blood transfusions; 1.2 blood units per patient had been meanly transfused. The mean fluoroscopy beam-on time was 195s per patient. The mean uterine dose was 26.75mGy. No pH anomalies were measured from the umbilical cord blood; the Apgar score at 5min was ≥8. The analysis of the neuro-developmental milestones showed normal cognitive development in all children at 6months. The uterine wall enhancement evaluated with contrast-enhanced MRI 6months after the embolization procedure showed preserved myometrial perfusion without area of necrosis. In this series of patients, the predelivery uterine arteries' embolization was a safe and effective procedure; this may represent a technical alternative that interventional radiologists can consider when facing this challenging scenario.

SU‐F‐I‐36: In‐Utero Dose Measurements Within Postmortem Subjects for Estimating Fetal Doses in Pregnant Patients Examined with Pulmonary Embolism, Trauma, and Appendicitis CT

Purpose:The imaging of pregnant patients is medically necessary in certain clinical situations. The purpose of this work was to directly measure uterine doses in a cadaver scanned with CT protocols commonly performed on pregnant patients in order to estimate fetal dose and assess potential risk.Method:One postmortem subject was scanned on a 320‐slice CT scanner with standard pulmonary embolism, trauma, and appendicitis protocols. All protocols were performed with the scan parameters and ranges currently used in clinical practice. Exams were performed both with and without iterative reconstruction to highlight the dose savings potential. Optically stimulated luminescent dosimeters (OSLDs) were inserted into the uterus in order to approximate fetal doses.Results:In the pulmonary embolism CT protocol, the uterus is outside of the primary beam, and the dose to the uterus was under 1 mGy. In the trauma and appendicitis protocols, the uterus is in the primary beam, the fetal dose estimates were 30.5 mGy for the trauma protocol, and 20.6 mGy for the appendicitis protocol. Iterative reconstruction reduced fetal doses by 30%, with uterine doses at 21.3 for the trauma and 14.3 mGy for the appendicitis protocol.Conclusion:Fetal doses were under 1 mGy when exposed to scatter radiation, and under 50 mGy when exposed to primary radiation with the trauma and appendicitis protocols. Consistent with the National Council on Radiation Protection &amp; Measurements (NCRP) and the International Commission on Radiological Protection (ICRP), these doses exhibit a negligible risk to the fetus, with only a small increased risk of cancer. Still, CT scans are not recommended during pregnancy unless the benefits of the exam clearly outweigh the potential risk. Furthermore, when possible, pregnant patients should be examined on CT scanners equipped with iterative reconstruction in order to keep patient doses as low as reasonable achievable.

Modelling maternal obesity: the effects of a chronic high-fat, high-cholesterol diet on uterine expression of contractile-associated proteins and ex vivo contractile activity during labour in the rat.

Maternal obesity is associated with prolonged and dysfunctional labour and emergency caesarean section, but the mechanisms are unknown. The present study investigated the effects of an adiposity-inducing high-fat, high-cholesterol (HFHC) diet on uterine contractile-associated protein (CAP) expression and ex vivo uterine contractility in term non-labouring (TNL) and term labouring (TL) rats. Female rats were fed either control chow (CON n=20) or HFHC (n=20) diet 6weeks before conception and during pregnancy. On gestational day 21 (TNL) or day 22 (TL) CON and HFHC (n=10) rats were killed to determine plasma cholesterol, triacylglycerol and progesterone concentrations and collection of myometrium for contractility studies and expression of CAPs caveolin-1 (Cav-1), connexin-43 (CX-43) and it's phosphorylated form (pCX-43), oxytocin receptor (OXTR) and cyclooxygenase-2 (COX-2). HFHC feeding increased visceral fat (P≤0.001), plasma cholesterol (P≤0.001) and triacylglycerol (P=0.039) concentrations. Stage of labour effected uterine expression of CAV-1 (P<0.02), pCX43 and COX-2 (both P<0.03). CAV-1 and pCX43 decreased but COX-2 increased with parturition. Significant diet- and labour-stage interactions were evident for CX-43 and pCX43 (P<0.03 and P<0.004 respectively). CX-43 decreased with TL in HFHC animals but was unaltered in CON. pCX-43 fell with labour in CON but remained high in HFHC. OXTR expression was significantly higher in HFHC compared with CON animals (P<0.03). Progesterone was higher in HFHC rats at term (P<0.014) but fell significantly with labour to similar concentrations as CON. Contractility studies identified synchronous contractions of stable amplitude in lean animals, but unstable asynchronous contractions with obesity. Uterine dose response to oxytocin was blunted during labour in HFHC rats with a log EC50 of -8.84 compared with -10.25M in CON for integral activity (P<0.05). In conclusion, our adiposity model exhibits adverse effects on contractile activity during labour that can be investigated further to unravel the mechanisms causing uterine dystocia in obese women.

EP-1515: Evaluation of organ motion and uterine dose summation for IMRT in locally advanced cervical cancer

EP-1515: Evaluation of organ motion and uterine dose summation for IMRT in locally advanced cervical cancer

Preserving Fertility in Adolescent Girls and Young Women Requiring Craniospinal Irradiation: A Case Report and Discussion of Options to Be Considered Prior to Treatment.

Craniospinal irradiation (CSI) is associated with infertility risk for adolescent/young adult women. We explore two methods of reducing ovarian exposure: oophoropexy (surgical removal of the ovaries from the path of the X-ray beam) and proton therapy (to allow the beam to stop without exposing the ovaries/uterus). In the case discussed, oophoropexy followed by X-ray CSI reduced ovarian dose to that at which 50% of oocytes are expected to survive, and the patient appears to have viable oocytes; this technique did not reduce uterine dose. Proton therapy would have eliminated the ovarian and uterine dose and the need for oophoropexy.

SU‐E‐T‐346: Dosimetric Evaluation of a High‐Dose‐Rate Modified‐Rotte “Y” Applicator for Treatment of Inoperable Endometrial Cancer

Purpose: Evaluate dosimetrically the use of a modified Rotte Y‐tandem applicator for HDR brachytherapy treatment of endometrial cancer. Methods: For inoperable endometrial cancer or patients of morbid obesity, the use of a Rotte Y‐dual tandem applicator has been an integral part of treating patients with large uterine widths. Ten patient plans were selected to dosimetrically evaluate the use of a modified Rotte applicator. A third tandem was placed anteriorly and superiorly to the two lateral dual tandems inside the uterine cavity. Each patient fraction was scanned with 5 mm slice thicknesses and exported to the Oncentra v4.1 treatment planning system. A second plan was created with the use the dual‐tandem applicator only. The maximum doses to the bladder, rectum, sigmoid, and intestines were found for each plan. Dose volume histograms were created to evaluate the treatments delivered. Oncentra Plan Analysis module was use to compare both plans. Results: Using the dose volume histograms, the uterine dose coverage for one treatment was at 20% when the modified Rotte applicator was used. The plan with the unmodified, dual‐tandem applicator covered 12% of uterine volume. Doses to the structures of interest were higher when the modified Rotte applicator was used, but all were still well below their dose tolerances. Conclusion: The use of the modified Rotte applicator with a third tandem can be used to effectively cover large uterine widths for the treatment of endometrial cancer.

Cancer Mortality FollowingIn UteroExposure Among Offspring of Female Mayak Worker Cohort Members

Little is known about long-term cancer risks following in utero radiation exposure. We evaluated the association between in utero radiation exposure and risk of solid cancer and leukemia mortality among 8,000 offspring, born from 1948-1988, of female workers at the Mayak Nuclear Facility in Ozyorsk, Russia. Mother's cumulative gamma radiation uterine dose during pregnancy served as a surrogate for fetal dose. We used Poisson regression methods to estimate relative risks (RRs) and 95% confidence intervals (CIs) of solid cancer and leukemia mortality associated with in utero radiation exposure and to quantify excess relative risks (ERRs) as a function of dose. Using currently available dosimetry information, 3,226 (40%) offspring were exposed in utero (mean dose = 54.5 mGy). Based on 75 deaths from solid cancers (28 exposed) and 12 (6 exposed) deaths from leukemia, in utero exposure status was not significantly associated with solid cancer: RR = 0.94, 95% CI 0.58 to 1.49; ERR/Gy = -0.1 (95% CI < -0.1 to 4.1), or leukemia mortality; RR = 1.65, 95% CI 0.52 to 5.27; ERR/Gy = -0.8 (95% CI < -0.8 to 46.9). These initial results provide no evidence that low-dose gamma in utero radiation exposure increases solid cancer or leukemia mortality risk, but the data are not inconsistent with such an increase. As the offspring cohort is relatively young, subsequent analyses based on larger case numbers are expected to provide more precise estimates of adult cancer mortality risk following in utero exposure to ionizing radiation.

Genetic Disease in the Children of Danish Survivors of Childhood and Adolescent Cancer

Preconception radiation and chemotherapy have the potential to produce germ cell mutations leading to genetic disease in the next generation. Dose-response relationships were evaluated between cancer treatments and untoward pregnancy outcomes. A case-cohort study was conducted involving 472 Danish survivors of childhood and adolescent cancer and their 1,037 pregnancies. Adverse outcomes included 159 congenital malformations, six chromosomal abnormalities, seven stillbirths, and nine neonatal deaths. Preconception radiation doses to the gonads, uterus, and pituitary gland and administered chemotherapy were quantified based on medical records and related to adverse outcomes using a generalized estimating equation model. No statistically significant associations were found between genetic disease in children and parental treatment with alkylating drugs or preconception radiation doses to the testes in male and ovaries in female cancer survivors. Specifically, the risk of genetic disease was similar among the children of irradiated survivors when compared with nonirradiated survivors (relative risk [RR], 1.02; 95% CI, 0.59 to 1.44; P = .94). A statistically significant association between abdomino-pelvic irradiation and malformations, stillbirths, and neonatal deaths was not seen in the children of female survivors overall (P = .07) or in the children of mothers receiving high uterine doses (mean, 13.5 Gy; max, 100 Gy; RR, 2.3; 95% CI, 0.95 to 5.56). Mutagenic chemotherapy and radiotherapy doses to the gonads were not associated with genetic defects in children of cancer survivors. However, larger studies need to be conducted to further explore potential associations between high-dose pelvic irradiation and specific adverse pregnancy outcomes.

The development of fetal dosimetry and its application to A-bomb survivors exposed in utero

The cohort of the atomic bomb survivors of Hiroshima and Nagasaki comprises the major basis for investigations of health effects induced by ionising radiation in humans. To study the health effects associated with radiation exposure before birth, fetal dosimetry is needed if significant differences exist between the fetal absorbed dose and the mother's uterine dose. Combining total neutron and gamma ray free-in-air fluences at 1 m above ground with fluence-to-absorbed dose conversion coefficients, fetal doses were calculated for various exposure orientations at the ground distance of 1500 m from the hypocentres in Hiroshima and Nagasaki. The results showed that the mother's uterine dose can serve as a good surrogate for the dose of the embryo and fetus in the first trimester. However, significant differences exist between doses of the fetus of different ages. If the mother's uterine dose were used as a surrogate, doses to the fetus in the last two trimesters could be overestimated by more than 20 % for exposure orientations facing towards and away from the hypocentre while significantly underestimated for lateral positions relative to the hypocentre. In newer fetal models, the brain is modelled for all fetal ages. Brain doses to the 3-month fetus are generally higher than those to an embryo and fetus of other ages. In most cases, brain absorbed doses differ significantly from the doses to the entire fetal body. In order to accurately assess radiation effects to the fetal brain, it is necessary to determine brain doses separately.