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2.
Ann Oncol ; 31(6): 780-788, 2020 06.
Article in English | MEDLINE | ID: mdl-32240793

ABSTRACT

BACKGROUND: Bromodomain and extra-terminal (BET) proteins are epigenetic readers that regulate expression of genes involved in oncogenesis. CC-90010 is a novel, oral, reversible, small-molecule BET inhibitor. PATIENTS AND METHODS: CC-90010-ST-001 (NCT03220347; 2015-004371-79) is a phase I dose-escalation and expansion study of CC-90010 in patients with advanced or unresectable solid tumors and relapsed/refractory (R/R) non-Hodgkin's lymphoma (NHL). We report results from the dose escalation phase, which explored 11 dose levels and four dosing schedules, two weekly (2 days on/5 days off; 3 days on/4 days off), one biweekly (3 days on/11 days off), and one monthly (4 days on/24 days off). The primary objectives were to determine the safety, maximum tolerated dose (MTD) and/or recommended phase II dose (RP2D) and schedule. Secondary objectives were to evaluate signals of early antitumor activity, pharmacokinetics, and pharmacodynamics. RESULTS: This study enrolled 69 patients, 67 with solid tumors and two with diffuse large B-cell lymphoma (DLBCL). The median age was 57 years (range, 21-80) and the median number of prior regimens was four (range, 1-9). Treatment-related adverse events (TRAEs) were mostly mild and manageable; grade 3/4 TRAEs reported in more than two patients were thrombocytopenia (13%), anemia, and fatigue (4% each). Six patients had dose-limiting toxicities. MTDs were 15 mg (2 days on/5 days off), 30 mg (3 days on/11 days off), and 45 mg (4 days on/24 days off). The RP2D and schedule selected for expansion was 45 mg (4 days on/24 days off). As of 8 October 2019, one patient with grade 2 astrocytoma achieved a complete response, one patient with endometrial carcinoma had a partial response, and six patients had prolonged stable disease ≥11 months. CONCLUSIONS: CC-90010 is well tolerated, with single-agent activity in patients with heavily pretreated, advanced solid tumors.


Subject(s)
Antineoplastic Agents , Lymphoma, Large B-Cell, Diffuse , Lymphoma, Non-Hodgkin , Adult , Aged , Aged, 80 and over , Antineoplastic Agents/adverse effects , Humans , Lymphoma, Large B-Cell, Diffuse/drug therapy , Lymphoma, Non-Hodgkin/drug therapy , Maximum Tolerated Dose , Middle Aged , Neoplasm Recurrence, Local/drug therapy , Young Adult
3.
Clin. transl. oncol. (Print) ; 20(6): 713-718, jun. 2018. ilus, tab, graf
Article in English | IBECS | ID: ibc-173619

ABSTRACT

Introduction: Hematologic toxicity (HT) in cervical cancer patients can cause treatment delays and reduction in chemotherapy, especially in high risk patients. Dose to PET-defined regions of active bone marrow (ABM) has been shown to correlate with cytopenias. An absolute volume of ABM spared may accurately represent hematopoietic reserve and risk of HT. This analysis evaluates whether the volume of ABM spared can more accurately predict HT compared to conventional dosimetric parameters. Methods: Thirty-one patients treated for cervical cancer with chemoradiation from 9/2011 to 8/2016 were retrospectively reviewed. Receiver operating characteristic (ROC) curve were used to assess optimal cutpoint criterions for grade 3+ HT based on the CTCAEv4. Conventional dosimetric parameters to PBM and ABM (mean dose, V10, V20, V40) were assessed as well as the absolute volume (cc) of PBM and ABM spared 10, 20, and 40 Gy. Results: The absolute volume of PBM spared 10 Gy (< 230 cc; AUC 0.732, p = 0.03) as well as volume of ABM spared 10 Gy (< 179 cc; AUC 0.815, p = 0.0002), spared 20 Gy (< 186 cc; AUC 0.774, p = 0.0015), and spared 40 Gy (< 738 cc; AUC 0.887, p < 0.0001) all predicted grade 3+ HT. In patients with < 738 cc of ABM spared 40 Gy, 18/18 (100%) had grade 3+ toxicity compared to 6/13 (46%) of patients with > 738 cc of ABM spared 40 Gy (p < 0.0001). Conclusion: The baseline volume of ABM and the fraction of ABM present in patients vary significantly. The ongoing NRG-GY006 trial and other efforts at bone marrow sparing use V10, V20, and mean dose to the ABM during planning optimization. This analysis suggests that the volume of ABM spared 40 Gy (> 738 cc) may be a stronger predictor of HT than conventional dosimetric parameters. This should be further evaluated for clinical use


No disponible


Subject(s)
Humans , Female , Adult , Middle Aged , Aged , Positron Emission Tomography Computed Tomography/methods , Uterine Cervical Neoplasms/therapy , Chemoradiotherapy/adverse effects , Toxicity Tests/methods , Radioisotopes/administration & dosage , Uterine Cervical Neoplasms/pathology , Bone Marrow , Bone Marrow/radiation effects , Retrospective Studies
4.
Clin Transl Oncol ; 20(6): 713-718, 2018 Jun.
Article in English | MEDLINE | ID: mdl-29076030

ABSTRACT

INTRODUCTION: Hematologic toxicity (HT) in cervical cancer patients can cause treatment delays and reduction in chemotherapy, especially in high risk patients. Dose to PET-defined regions of active bone marrow (ABM) has been shown to correlate with cytopenias. An absolute volume of ABM spared may accurately represent hematopoietic reserve and risk of HT. This analysis evaluates whether the volume of ABM spared can more accurately predict HT compared to conventional dosimetric parameters. METHODS: Thirty-one patients treated for cervical cancer with chemoradiation from 9/2011 to 8/2016 were retrospectively reviewed. Receiver operating characteristic (ROC) curve were used to assess optimal cutpoint criterions for grade 3+ HT based on the CTCAEv4. Conventional dosimetric parameters to PBM and ABM (mean dose, V10, V20, V40) were assessed as well as the absolute volume (cc) of PBM and ABM spared 10, 20, and 40 Gy. RESULTS: The absolute volume of PBM spared 10 Gy (< 230 cc; AUC 0.732, p = 0.03) as well as volume of ABM spared 10 Gy (< 179 cc; AUC 0.815, p = 0.0002), spared 20 Gy (< 186 cc; AUC 0.774, p = 0.0015), and spared 40 Gy (< 738 cc; AUC 0.887, p < 0.0001) all predicted grade 3+ HT. In patients with < 738 cc of ABM spared 40 Gy, 18/18 (100%) had grade 3+ toxicity compared to 6/13 (46%) of patients with > 738 cc of ABM spared 40 Gy (p < 0.0001). CONCLUSION: The baseline volume of ABM and the fraction of ABM present in patients vary significantly. The ongoing NRG-GY006 trial and other efforts at bone marrow sparing use V10, V20, and mean dose to the ABM during planning optimization. This analysis suggests that the volume of ABM spared 40 Gy (> 738 cc) may be a stronger predictor of HT than conventional dosimetric parameters. This should be further evaluated for clinical use.


Subject(s)
Bone Marrow/pathology , Chemoradiotherapy/adverse effects , Hematologic Diseases/diagnosis , Positron-Emission Tomography/methods , Uterine Cervical Neoplasms/therapy , Adult , Aged , Bone Marrow/diagnostic imaging , Bone Marrow/drug effects , Bone Marrow/radiation effects , Female , Follow-Up Studies , Hematologic Diseases/diagnostic imaging , Hematologic Diseases/etiology , Humans , Middle Aged , Prognosis , Retrospective Studies , Uterine Cervical Neoplasms/diagnostic imaging , Uterine Cervical Neoplasms/pathology
7.
Clin Pharmacol Ther ; 101(6): 745-753, 2017 Jun.
Article in English | MEDLINE | ID: mdl-27859030

ABSTRACT

Extended-release (XR) formulations enable less frequent dosing vs. conventional (e.g., immediate release (IR)) formulations. Regulatory registration of such formulations typically requires pharmacokinetic (PK) and clinical efficacy data. Here we illustrate a model-informed, exposure-response (E-R) approach to translate controlled trial data from one formulation to another without a phase III trial, using a tofacitinib case study. Tofacitinib is an oral Janus kinase (JAK) inhibitor for the treatment of rheumatoid arthritis (RA). E-R analyses were conducted using validated clinical endpoints from phase II dose-response and nonclinical dose fractionation studies of the IR formulation. Consistent with the delay in clinical response dynamics relative to PK, average concentration was established as the relevant PK parameter for tofacitinib efficacy and supported pharmacodynamic similarity. These evaluations, alongside demonstrated equivalence in total systemic exposure between IR and XR formulations, provided the basis for the regulatory approval of tofacitinib XR once daily by the US Food and Drug Administration.


Subject(s)
Antineoplastic Agents/administration & dosage , Antineoplastic Agents/pharmacokinetics , Janus Kinases/antagonists & inhibitors , Models, Biological , Neoplasms/drug therapy , Piperidines/administration & dosage , Protein Kinase Inhibitors/administration & dosage , Protein Kinase Inhibitors/pharmacokinetics , Pyrimidines/administration & dosage , Pyrroles/administration & dosage , Administration, Oral , Animals , Antineoplastic Agents/adverse effects , Antineoplastic Agents/chemistry , Area Under Curve , Delayed-Action Preparations , Drug Administration Schedule , Drug Approval , Humans , Janus Kinases/metabolism , Male , Metabolic Clearance Rate , Models, Animal , Neoplasms/enzymology , Neoplasms/pathology , Piperidines/chemistry , Piperidines/pharmacokinetics , Protein Kinase Inhibitors/adverse effects , Protein Kinase Inhibitors/chemistry , Pyrimidines/chemistry , Pyrimidines/pharmacokinetics , Pyrroles/chemistry , Pyrroles/pharmacokinetics , Rats, Sprague-Dawley , Therapeutic Equivalency , Treatment Outcome , United States , United States Food and Drug Administration
8.
Am J Transplant ; 15(6): 1644-53, 2015 Jun.
Article in English | MEDLINE | ID: mdl-25649117

ABSTRACT

Tofacitinib fixed-dose regimens attained better kidney function and comparable efficacy to cyclosporine (CsA) in kidney transplant patients, albeit with increased risks of certain adverse events. This post-hoc analysis evaluated whether a patient subgroup with an acceptable risk-benefit profile could be identified. Tofacitinib exposure was a statistically significant predictor of serious infection rate. One-hundred and eighty six kidney transplant patients were re-categorized to above-median (AME) or below-median (BME) exposure groups. The 6-month biopsy-proven acute rejection rates in AME, BME and CsA groups were 7.8%, 15.7% and 17.7%, respectively. Measured glomerular filtration rate was higher in AME and BME groups versus CsA (61.2 and 67.9 vs. 53.9 mL/min) at Month 12. Fewer patients developed interstitial fibrosis and tubular atrophy (IF/TA) at Month 12 in AME (20.5%) and BME (27.8%) groups versus CsA (48.3%). Serious infections occurred more frequently in the AME group (53.0%) than in BME (28.4%) or CsA (25.5%) groups. Posttransplant lymphoproliferative disorder (PTLD) only occurred in the AME group. In kidney transplant patients, the BME group preserved the clinical advantage of comparable acute rejection rates, improved renal function and a lower incidence of IF/TA versus CsA, and with similar rates of serious infection and no PTLD.


Subject(s)
Graft Rejection/prevention & control , Immunosuppressive Agents/adverse effects , Kidney Transplantation , Kidney/physiopathology , Piperidines/adverse effects , Pyrimidines/adverse effects , Pyrroles/adverse effects , Adult , Biopsy , Cyclosporine/adverse effects , Cyclosporine/pharmacology , Cyclosporine/therapeutic use , Dose-Response Relationship, Drug , Female , Glomerular Filtration Rate/drug effects , Glomerular Filtration Rate/physiology , Graft Rejection/epidemiology , Humans , Immunosuppressive Agents/pharmacology , Immunosuppressive Agents/therapeutic use , Kidney/drug effects , Kidney/pathology , Lymphoproliferative Disorders/epidemiology , Male , Middle Aged , Piperidines/pharmacology , Piperidines/therapeutic use , Pyrimidines/pharmacology , Pyrimidines/therapeutic use , Pyrroles/pharmacology , Pyrroles/therapeutic use , Randomized Controlled Trials as Topic , Risk Assessment , Risk Factors
9.
Head Neck Pathol ; 7(4): 381-8, 2013 Dec.
Article in English | MEDLINE | ID: mdl-23821219

ABSTRACT

Salivary gland lymphoproliferative disorders (SGLD) are very rare tumors and clinicopathological data is sparse. In a Canadian series of 30 cases, extracted from the surgical pathology files of The Ottawa Hospital between 1990 and 2010, a clinical, histopathological, and immunophenotypic analysis was conducted. Tumors were staged using the Ann Arbor staging and classified using the World Health Organization 2008 classification. There were 15 salivary gland (SG) primary lymphomas with localized disease, predominantly mucosa associated lymphoid tissue type marginal zone lymphoma (MALT-L), but with a significant incidence of low grade follicular lymphoma (FL) and diffuse large B cell phenotype as well. There were 7 systemic SG lymphomas and 5 patients were diagnosed with lymphoproliferative disorders originating from intra-parotid lymph nodes. Finally, the remaining 3 cases represented reactive sialadenitis. A literature review was conducted and our primary lymphoma group was compared to those from other countries. SGLDs are predominantly B cell lymphomas that develop in older adults. Primary tumors, which have MALT-L and low grade FL characteristics, have a favorable survival, however MALT-L have a high rate of relapse. A minority of SG lesions are excised secondary to lymphomas that definitely arose from intra-parotid lymph nodes.


Subject(s)
Lymphoma/pathology , Salivary Gland Neoplasms/pathology , Canada/epidemiology , Female , Humans , Lymphoma/epidemiology , Lymphoproliferative Disorders/epidemiology , Lymphoproliferative Disorders/pathology , Male , Middle Aged , Salivary Gland Diseases/epidemiology , Salivary Gland Diseases/pathology , Salivary Gland Neoplasms/epidemiology , Tertiary Care Centers
10.
Br J Dermatol ; 169(1): 137-45, 2013 07.
Article in English | MEDLINE | ID: mdl-23387374

ABSTRACT

BACKGROUND: Tofacitinib (CP-690,550) is a novel Janus kinase inhibitor in development as an oral formulation for the treatment of several inflammatory diseases including psoriasis. OBJECTIVES: This phase 2a study aimed to assess the efficacy, systemic safety, local tolerability and systemic pharmacokinetics of topical tofacitinib in mild-to-moderate plaque psoriasis. METHODS: Two tofacitinib ointment formulations were evaluated in this multicentre, double-blind, vehicle-controlled trial (NCT01246583). Seventy-one patients were randomized 2 : 1 : 2 : 1 to 2% tofacitinib ointment 1, vehicle 1, 2% tofacitinib ointment 2 and vehicle 2, each administered twice daily for 4 weeks to a single fixed 300 cm(2) treatment area containing a target plaque with or without one or more nontarget plaques and normal skin. RESULTS: The primary endpoint of percentage change from baseline in the Target Plaque Severity Score at week 4 demonstrated statistically significant improvement for ointment 1 [least squares mean (LSM) -54.4%] vs. vehicle 1 (LSM -41.5%), but not ointment 2 (LSM -24.2%) vs. vehicle 2 (LSM -17.2%). Secondary endpoints (target plaque area and Itch Severity Item) improved similarly for tofacitinib ointment vs. corresponding vehicle. Adverse event (AE) occurrence was similar across treatment groups. All AEs were mild or moderate and none were serious or led to subject discontinuation. One application-site AE (erythema) was reported. Tofacitinib mean systemic exposure was minimal and was greater for ointment 1 than for ointment 2. CONCLUSIONS: Tofacitinib ointment 1 was well tolerated and efficacious compared with vehicle for the treatment of plaque psoriasis. Further study of topical tofacitinib for psoriasis treatment is warranted.


Subject(s)
Dermatologic Agents/administration & dosage , Piperidines/administration & dosage , Protein Kinase Inhibitors/administration & dosage , Psoriasis/drug therapy , Pyrimidines/administration & dosage , Pyrroles/administration & dosage , Administration, Cutaneous , Adult , Aged , Chronic Disease , Dermatologic Agents/adverse effects , Dermatologic Agents/pharmacokinetics , Double-Blind Method , Drug Administration Schedule , Female , Humans , Male , Middle Aged , Ointments , Piperidines/adverse effects , Piperidines/pharmacokinetics , Protein Kinase Inhibitors/adverse effects , Protein Kinase Inhibitors/pharmacokinetics , Pyrimidines/adverse effects , Pyrimidines/pharmacokinetics , Pyrroles/adverse effects , Pyrroles/pharmacokinetics , Treatment Outcome , Young Adult
13.
J Pediatr Endocrinol Metab ; 12(4): 525-30, 1999.
Article in English | MEDLINE | ID: mdl-10417968

ABSTRACT

UNLABELLED: It is known that in thalassemic patients there is a disproportion between lower and upper segments whose causes have not yet been identified. We evaluated whether the administration of estrogens to induce puberty in hypogonadic thalassemic girls caused an inappropriate acceleration of bone maturation and whether this had a negative influence on final and sitting height. MATERIALS AND METHODS: Twelve thalassemic patients with spontaneous puberty (Group A) and seven patients with hypogonadism (Group B) were studied. The mutations of the beta gene were identified by DNA analysis. We took into account four observations, ranging from the onset of spontaneous puberty in group A or the start of substitutive therapy in group B, to 5 years later. At each observation we considered: chronological age (CA), bone age (BA), height (Ht) expressed in cm and as standard deviation score (HtSDS) calculated with respect to CA (HtSDSCA) and BA (HtSDSBA), growth spurt, sitting height, expressed as SDS (SH-SDS), and height gain (HG). The delta BA and delta CA were calculated between the first and the final observation values to evaluate the bone age acceleration (delta BA/delta CA). RESULTS: No acceleration of BA was noted. delta BA/delta CA was 0.98 +/- 0.1 in group A and 0.89 +/- 0.1 in group B (p > 0.05). All patients in group B had the most severe form (beta degree/beta degree) of thalassemia. During the final observation, SH-SDS was -1.43 +/- 1.2 and -2.9 +/- 0.6 in group A and B respectively (p < 0.002), while no difference between the two groups for HtSDSCA and HtSDSBA was observed. HG was greater in group A than in group B (17.7 +/- 5.4 cm vs 10.8 +/- 5.2 cm) (p < 0.002), such as the spurt 8.6 +/- 1.4 cm (group A) and 6.1 +/- 2.6 cm (group B) (p < 0.05). CONCLUSIONS: Girls with hypogonadism did not show an inappropriate acceleration of BA, as they reached near final height similar to girls with spontaneous puberty. The auxological parameters showed a more severe body disproportion with the prevalence of the lower segment in the hypogonadic girls. This could be explained by a higher degree of bone marrow hyperplasia related to the most severe form of thalassemia and a higher blood consumption. As a consequence, damage at the vertebral level might determine an inability of the bone tissue to respond to estrogens. We suggest beginning estrogen therapy earlier in order to obtain better truncal growth.


Subject(s)
Age Determination by Skeleton , Body Height , Ethinyl Estradiol/therapeutic use , Puberty, Delayed/drug therapy , beta-Thalassemia/complications , Adolescent , Adult , Chelating Agents/adverse effects , Chelating Agents/therapeutic use , Deferoxamine/adverse effects , Deferoxamine/therapeutic use , Ethinyl Estradiol/administration & dosage , Female , Humans , Hypogonadism/drug therapy , Hypogonadism/etiology , Medroxyprogesterone Acetate/administration & dosage , Medroxyprogesterone Acetate/therapeutic use , Posture , Puberty, Delayed/etiology , beta-Thalassemia/drug therapy
14.
Free Radic Res ; 30(6): 453-62, 1999 Jun.
Article in English | MEDLINE | ID: mdl-10400457

ABSTRACT

It has been reported that iron overload in beta-thalassemia leads to an enhanced generation of reactive oxygen species and to oxidative stress. We have studied the oxidant/antioxidant imbalance in the blood of 48 transfusion-dependent beta-thalassemic patients (TLP) (17 males, 31 females, 11-22 year), under chelation therapy, and in 40 sex and age matched healthy controls (CTR). Plasma and lymphocyte levels of vitamin E (Vit E), ubiquinol (CoQ10H2), ubiquinone (CoQ10), plasma concentrations of vitamin A (Vit A), beta-carotene, lycopene, vitamin C (Vit C), total thiols, fatty acid patterns of phospholipids (PL-FA), and plasma and urinary markers of lipoperoxidation (TBA-RM, conjugated dienes, and azelaic acid (AZA), as well as the urinary levels of catecholamine and serotonin metabolites, were evaluated by gas chromatography-mass spectrometry (GC-MS), HPLC and spectrophotometry. Routine laboratory blood analyses were performed on the same samples; 39/48 TLP were HCV positive. Blood samples were collected just before transfusion, the 24 h urine samples the day before. Our results clearly showed that a severe oxidative stress occurs in the plasma of TLP in comparison with CTR. In fact, the levels of lipophilic antioxidants and ascorbate were severely depleted: CoQ10H2 (-62.5%), total CoQ10 (-35.1%), Vit E (-43.8%), beta-carotene (-31.1%), lycopene (-63.7%), Vit A (-35.9%), Vit C (-23.1%). The impairment of the antioxidant status was associated with elevated plasma levels of by-products of lipoperoxidation and urinary concentrations of catecholamine metabolites and of AZA, indicating a high degree of both neurological stress and lipoperoxidation. A significant positive correlation was found between vitamin E and non-transferrin-bound iron (NTBI) (r = -0.81; p < 0.001), while no correlation was found between antioxidant depletion and ferritin serum levels, average blood consumption, or the presence of clinical complications. The administration of selective antioxidants along with an appropriate diet might represent a promising way of counteracting oxidative damage and its deleterious effects on the progression of the disease.


Subject(s)
Antioxidants/analysis , Catecholamines/urine , beta-Thalassemia/metabolism , Adolescent , Adult , Bilirubin/blood , Carotenoids/blood , Catecholamines/metabolism , Child , Fatty Acids/blood , Fatty Acids/metabolism , Female , Ferritins/blood , Humans , Iron/blood , Lipid Peroxidation , Male , Oxidative Stress , Serotonin/metabolism , Serotonin/urine , Sulfhydryl Compounds/blood , Ubiquinone/analogs & derivatives , Ubiquinone/blood , Uric Acid/blood , Vitamins/blood , beta-Thalassemia/blood , beta-Thalassemia/urine
15.
Phys Med Biol ; 43(5): 1147-58, 1998 May.
Article in English | MEDLINE | ID: mdl-9623646

ABSTRACT

A position-sensitive detector chamber is introduced for the three-dimensional (3D) dosimetry of photon-emitting brachytherapy sources. The detector is based on an extremely fine suspension of monochloropentafluoroethane droplets emulsified in a gel. The droplets are highly superheated at room temperature and their evaporation can be triggered by photon interactions, leading to the formation of microscopic bubbles. Thus, when photon-emitting brachytherapy sources are inserted into the detector, bubble distributions form around them, enabling visualization of the radiation field. The tissue-equivalent emulsifier gel is highly viscous and keeps the bubbles immobilized at the location of their formation. Bubbles can then be imaged by nuclear magnetic resonance or optical scanning techniques. After the imaging, the detector can be pressurized in order to recondense the bubbles to the liquid phase. In a few minutes, the device is annealed and ready to be used again for repeated measurements improving the counting statistics. The photon sensitivity of the monochloropentafluoroethane droplets was determined with highly filtered, quasi-monochromatic x-ray beams and radionuclide gamma sources. The air-kerma response presents a broad maximum at low energies, due to the relatively high effective atomic number of the halocarbon molecule. A prototype chamber was built and successfully tested: bubble distributions deriving from the insertion of a 125I source were imaged by means of a slice-selective 3D gradient-echo technique. These experiments confirm the potential and viability of this new approach to 3D photon dosimetry.


Subject(s)
Brachytherapy/methods , Phantoms, Imaging , Photons/therapeutic use , Radiotherapy Planning, Computer-Assisted/methods , Chlorofluorocarbons, Methane , Emulsions , Gamma Rays , Gels , Magnetic Resonance Imaging , Magnetic Resonance Spectroscopy , Radiotherapy Dosage , Viscosity , X-Rays
16.
Med Dosim ; 23(1): 27-9, 1998.
Article in English | MEDLINE | ID: mdl-9586716

ABSTRACT

The use of non-coplanar conformal therapy necessitates the use of unusual beam projections that may not be accomplished with a conventional linear accelerator table top. Modification of the table top can increase the available combinations of gantry and couch rotation. A standard Philips table top, supplied with an SL 75-5 linear accelerator, was modified to increase available combinations of gantry and couch rotation. This was accomplished by shortening the length and decreasing the width of the table top. The modified table top increases the combinations of gantry and couch angles significantly, simplifying the delivery of non-coplanar conformal therapy without significant compromise to routine treatment. The modification of a standard linear accelerator table top has increased the available combinations of gantry and couch rotation to accommodate non-coplanar conforrmal radiotherapy.


Subject(s)
Brain Neoplasms/radiotherapy , Particle Accelerators/instrumentation , Humans , Radiotherapy/instrumentation , Radiotherapy/methods
17.
J Pediatr Endocrinol Metab ; 11 Suppl 3: 997-9, 1998.
Article in English | MEDLINE | ID: mdl-10091184

ABSTRACT

We describe the occurrence of hypothyroidism and hypogonadotropic hypogonadism in an XY pseudohermaphrodite subject affected by beta-thalassemia. The patient, reared as female, diagnosed at 14 months of age as having a beta 39/Lepore hemoglobinopathy, treated with multiple transfusion therapy, was referred at age of 15 years because of delayed puberty. Complete endocrine evaluation showed low levels, both basal and after combined LHRH-TRH and hCG stimuli, of FSH, LH, TSH, estradiol (E2), testosterone (T), progesterone (P), androstenedione (A), and FT4 levels, and normal PRL, cortisol, 17OHP and ACTH levels. Imaging studies (ultrasound, magnetic resonance, radioisotope scanning and gonadal vessels phlebography) did not show internal genitalia and gonads. Karyotype resulted 46,XY. PCR amplification of the SRY gene confirmed the presence of the Y chromosome. Female genitalia without uterus in a subject with Y chromosome SRY gene, and no detectable testes indicate a condition of male pseudohermaphroditism associated with testicular regression. Low gonadotropin and sex steroid levels are suggestive of combined acquired hypothalamic-pituitary and gonadal impairment, due to iron deposition in both organs. We cannot exclude congenital failure of testosterone synthesis and action in this case, because lack of gonads is an unusual finding in thalassemic hypogonadic subjects.


Subject(s)
Disorders of Sex Development/complications , Hemoglobinopathies/complications , Hemoglobins, Abnormal , Hypogonadism/complications , Hypothyroidism/complications , beta-Thalassemia/complications , Adolescent , Gonadal Steroid Hormones/blood , Gonadotropin-Releasing Hormone , Gonadotropins, Pituitary/blood , Humans , Karyotyping , Male , Pituitary Diseases/complications , Puberty, Delayed , Thyroid Hormones/blood , Thyrotropin-Releasing Hormone
18.
Med Phys ; 25(12): 2316-25, 1998 Dec.
Article in English | MEDLINE | ID: mdl-9874823

ABSTRACT

This paper describes development of magnetic resonance imaging (MRI) techniques for three-dimensional (3D) imaging of a position-sensitive detector for brachytherapy dosimetry. The detector is a 0.5 l chamber containing an emulsion of halocarbon-115 droplets in a tissue-equivalent glycerin-based gel. The halocarbon droplets are highly superheated and expand into vapor microbubbles upon irradiation. Brachytherapy sources can be inserted into the superheated emulsion chamber to create distributions of bubbles. Three-dimensional MRI of the chamber is then performed. A 3D gradient-echo technique was optimized for spatial resolution and contrast between bubbles and gel. Susceptibility gradients at the interfaces between bubbles and gel are exploited to enhance contrast so microscopic bubbles can be imaged using relatively large voxel sizes. Three-dimensional gradient-echo images are obtained with an isotropic resolution of 300 microns over a 77 mm x 77 mm x 9.6 mm field-of-view in an imaging time of 14 min. A post-processing technique was developed to semi-automatically segment the bubbles from the images and to assess dose distributions based on the measured bubble densities. Relative dose distributions are computed from MR images for a 125I brachytherapy source and the results compare favorably to relative radial dose distributions calculated as recommended by Task Group 43 of the American Association of Physicists in Medicine.


Subject(s)
Brachytherapy/statistics & numerical data , Magnetic Resonance Imaging/methods , Radiometry/instrumentation , Algorithms , Emulsions , Equipment Design , Hot Temperature , Humans , Models, Theoretical , Radiometry/statistics & numerical data
19.
Med Phys ; 24(9): 1527-9, 1997 Sep.
Article in English | MEDLINE | ID: mdl-9304583

ABSTRACT

This study compared the relative effectiveness of TLD crystals LiF:Mg,Ti (TLD-100) and LiF:Mg,Cu,P (TLD-700H) for clinical dosimetry, focusing on reproducibility, linearity, and energy response. Experimental results indicated that TLD-700H was superior to TLD-100 with regard to reproducibility, lack of supralinearity, and the absence of variation in TL signal with radiation quality. TLD-700H also had the additional advantages of higher sensitivity and immediate readability. The investigators conclude that this relatively new TLD crystal shows promising potential for clinical dosimetry.


Subject(s)
Thermoluminescent Dosimetry/methods , Biophysical Phenomena , Biophysics , Copper , Crystallization , Evaluation Studies as Topic , Fluorides , Humans , Lithium Compounds , Magnesium , Phosphorus , Reproducibility of Results , Sensitivity and Specificity , Thermoluminescent Dosimetry/instrumentation , Thermoluminescent Dosimetry/statistics & numerical data , Titanium
20.
Med Phys ; 24(2): 241-9, 1997 Feb.
Article in English | MEDLINE | ID: mdl-9048364

ABSTRACT

The algorithm presented here for optimizing brachytherapy dose distributions is based on the idea that the seed distribution can be modeled as an activity distribution determined analogously to gamma camera imaging. The peripheral dose to the tumor is converted to a set of uncollimated projection data that are then filtered and backprojected to produce an initial seed distribution. The actual doses resulting from the seed placement are used to correct the initial projection data for attenuation, scatter, and lack of collimation. The corrected projection data are backprojected a second time to yield the optimized but unconstrained seed distribution. Clinical constraints such as the number of different seed activities, the maximum seed activity, the minimum peripheral tumor dose, and the minimum percentage of the volume which receives less than a specified dose are then applied to the unconstrained solution. Through the entire process, the dose calculations are functions of source anisotropy, scatter, and attenuation. When applied to a set of elliptical contours, the algorithm produces elliptical peripheral dose isodose contours and reasonable dose volume histograms for a constrained solution. The results for actual patient prostate contours were not as good, primarily because of the difficulties encountered in dealing with the irregular geometry of the prostate. However, the algorithm shows promise for further research.


Subject(s)
Algorithms , Brachytherapy/methods , Iodine Radioisotopes/therapeutic use , Prostatic Neoplasms/radiotherapy , Biophysical Phenomena , Biophysics , Humans , Male , Prostatic Neoplasms/diagnostic imaging , Radionuclide Imaging , Radiotherapy Dosage
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