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Radiotherapy and Oncology : Journal of... Jan 2014A substantial reduction of uncertainties in clinical brachytherapy should result in improved outcome in terms of increased local control and reduced side effects. Types... (Review)
Review
BACKGROUND AND PURPOSE
A substantial reduction of uncertainties in clinical brachytherapy should result in improved outcome in terms of increased local control and reduced side effects. Types of uncertainties have to be identified, grouped, and quantified.
METHODS
A detailed literature review was performed to identify uncertainty components and their relative importance to the combined overall uncertainty.
RESULTS
Very few components (e.g., source strength and afterloader timer) are independent of clinical disease site and location of administered dose. While the influence of medium on dose calculation can be substantial for low energy sources or non-deeply seated implants, the influence of medium is of minor importance for high-energy sources in the pelvic region. The level of uncertainties due to target, organ, applicator, and/or source movement in relation to the geometry assumed for treatment planning is highly dependent on fractionation and the level of image guided adaptive treatment. Most studies to date report the results in a manner that allows no direct reproduction and further comparison with other studies. Often, no distinction is made between variations, uncertainties, and errors or mistakes. The literature review facilitated the drafting of recommendations for uniform uncertainty reporting in clinical BT, which are also provided. The recommended comprehensive uncertainty investigations are key to obtain a general impression of uncertainties, and may help to identify elements of the brachytherapy treatment process that need improvement in terms of diminishing their dosimetric uncertainties. It is recommended to present data on the analyzed parameters (distance shifts, volume changes, source or applicator position, etc.), and also their influence on absorbed dose for clinically-relevant dose parameters (e.g., target parameters such as D90 or OAR doses). Publications on brachytherapy should include a statement of total dose uncertainty for the entire treatment course, taking into account the fractionation schedule and level of image guidance for adaptation.
CONCLUSIONS
This report on brachytherapy clinical uncertainties represents a working project developed by the Brachytherapy Physics Quality Assurances System (BRAPHYQS) subcommittee to the Physics Committee within GEC-ESTRO. Further, this report has been reviewed and approved by the American Association of Physicists in Medicine.
Topics: Brachytherapy; Dose Fractionation, Radiation; Humans; Neoplasms; Practice Guidelines as Topic; Uncertainty
PubMed: 24299968
DOI: 10.1016/j.radonc.2013.11.002 -
Radiotherapy and Oncology : Journal of... Mar 2018Model-based dose calculation algorithms (MBDCAs) have evolved from serving as a research tool into clinical practice in brachytherapy. This study investigates primary... (Review)
Review
BACKGROUND AND PURPOSE
Model-based dose calculation algorithms (MBDCAs) have evolved from serving as a research tool into clinical practice in brachytherapy. This study investigates primary sources of tissue elemental compositions used as input to MBDCAs and the impact of their variability on MBDCA-based dosimetry.
MATERIALS AND METHODS
Relevant studies were retrieved through PubMed. Minimum dose delivered to 90% of the target (D), minimum dose delivered to the hottest specified volume for organs at risk (OAR) and mass energy-absorption coefficients (μ/ρ) generated by using EGSnrc "g" user-code were compared to assess the impact of compositional variability.
RESULTS
Elemental composition for hydrogen, carbon, oxygen and nitrogen are derived from the gross contents of fats, proteins and carbohydrates for any given tissue, the compositions of which are taken from literature dating back to 1940-1950. Heavier elements are derived from studies performed in the 1950-1960. Variability in elemental composition impacts greatly D for target tissues and doses to OAR for brachytherapy with low energy sources and less for Ir-based brachytherapy. Discrepancies in μ/ρ are also indicative of dose differences.
CONCLUSIONS
Updated elemental compositions are needed to optimize MBDCA-based dosimetry. Until then, tissue compositions based on gross simplifications in early studies will dominate the uncertainties in tissue heterogeneity.
Topics: Algorithms; Body Composition; Brachytherapy; Humans; Organs at Risk; Radiotherapy Dosage; Uncertainty
PubMed: 29428259
DOI: 10.1016/j.radonc.2018.01.007 -
Health Physics Feb 2019Radiation protection in brachytherapy entails protecting members of the public, radiation professionals, and the patient from unnecessary radiation, as well as making...
Radiation protection in brachytherapy entails protecting members of the public, radiation professionals, and the patient from unnecessary radiation, as well as making sure that the radiation used in the patient's treatment is placed correctly with the correct dose distribution. Protecting members of the public from radiation emanating from brachytherapy sources implanted in a patient was an issue several decades ago, but with modern brachytherapy, the problem has mostly disappeared. The most frequent treatments are either low-dose-rate permanent implants for prostate cancer, or high-dose-rate procedures for gynecological, breast, or skin cancers. Almost all current permanent implants use low-energy photon sources that are shielded by the patient. Similarly, some temporary implants, such as eye plaques that also use low-energy photon sources, incorporate a metallic shield into the applicator. All high-dose-rate brachytherapy takes place in a treatment vault, in a manner similar to external-beam radiotherapy, thus eliminating exposure to members of the public, in the absence of some terrible error or mistake. Modern brachytherapy techniques either eliminate or greatly reduce radiation exposures to the brachytherapy staff also. As noted above, high-dose-rate treatments take place in a heavily shielded vault, and staff remain outside the vault when the source is out of its shielded housing. For low-energy permanent implants, facilities often order the sources loaded into the implant needles by the vendor, reducing the time the procedure staff is exposed to the source. Often, the loaded needles can be shielded while awaiting implantation. Alternatively, individual sources may be placed using a special applicator that shields the staff. Radiation protection of the patient in many respects differs little from how it was decades ago except for greatly increased precision. Assaying the strength of a source of any kind is still essential. As important as verifying the source strength is ensuring that the source will be in the correct location for the desired time. Imaging serves as the main mechanism to guide the implantation and verify source or applicator position. Modern imaging has unveiled anatomy exquisitely and often permits definition of target disease and neighboring normal structures sufficiently to allow very conformal dose distributions. Despite these great advances and capabilities, errors and mistakes (together called failures) still occur. Failures in health care overall are the third leading cause of death in the United States. Most treatment failures result not from equipment problems but from procedures gone wrong. Attention to comprehensive commissioning of both equipment and procedures and risk-based development of quality management procedures helps protect the patient. Patient safety organizations, established by the Agency for Healthcare Research and Quality, work with client facilities to help identify weaknesses in both treatment procedures and quality management and to develop improvements to enhance protection.
Topics: Brachytherapy; Humans; Patient Safety; Quality of Health Care; Radiation Protection
PubMed: 30585963
DOI: 10.1097/HP.0000000000001005 -
Medical Physics Oct 2015The authors present a novel paddle-based rotating-shield brachytherapy (P-RSBT) method, whose radiation-attenuating shields are formed with a multileaf collimator (MLC),...
PURPOSE
The authors present a novel paddle-based rotating-shield brachytherapy (P-RSBT) method, whose radiation-attenuating shields are formed with a multileaf collimator (MLC), consisting of retractable paddles, to achieve intensity modulation in high-dose-rate brachytherapy.
METHODS
Five cervical cancer patients using an intrauterine tandem applicator were considered to assess the potential benefit of the P-RSBT method. The P-RSBT source used was a 50 kV electronic brachytherapy source (Xoft Axxent™). The paddles can be retracted independently to form multiple emission windows around the source for radiation delivery. The MLC was assumed to be rotatable. P-RSBT treatment plans were generated using the asymmetric dose-volume optimization with smoothness control method [Liu et al., Med. Phys. 41(11), 111709 (11pp.) (2014)] with a delivery time constraint, different paddle sizes, and different rotation strides. The number of treatment fractions (fx) was assumed to be five. As brachytherapy is delivered as a boost for cervical cancer, the dose distribution for each case includes the dose from external beam radiotherapy as well, which is 45 Gy in 25 fx. The high-risk clinical target volume (HR-CTV) doses were escalated until the minimum dose to the hottest 2 cm(3) (D(2cm(3)) of either the rectum, sigmoid colon, or bladder reached their tolerance doses of 75, 75, and 90 Gy3, respectively, expressed as equivalent doses in 2 Gy fractions (EQD2 with α/β = 3 Gy).
RESULTS
P-RSBT outperformed the two other RSBT delivery techniques, single-shield RSBT (S-RSBT) and dynamic-shield RSBT (D-RSBT), with a properly selected paddle size. If the paddle size was angled at 60°, the average D90 increases for the delivery plans by P-RSBT on the five cases, compared to S-RSBT, were 2.2, 8.3, 12.6, 11.9, and 9.1 Gy10, respectively, with delivery times of 10, 15, 20, 25, and 30 min/fx. The increases in HR-CTV D90, compared to D-RSBT, were 16.6, 12.9, 7.2, 3.7, and 1.7 Gy10, respectively. P-RSBT HR-CTV D90-values were insensitive to the paddle size for paddles angled at less than 60°. Increasing the paddle angle from 5° to 60° resulted in only a 0.6 Gy10 decrease in HR-CTV D90 on average for five cases when the delivery times were set to 15 min/fx. The HR-CTV D90 decreased to 2.5 and 11.9 Gy10 with paddle angles of 90° and 120°, respectively.
CONCLUSIONS
P-RSBT produces treatment plans that are dosimetrically and temporally superior to those of S-RSBT and D-RSBT, although P-RSBT systems may be more mechanically challenging to develop than S-RSBT or D-RSBT. A P-RSBT implementation with 4-6 shield paddles would be sufficient to outperform S-RSBT and D-RSBT if delivery times are constrained to less than 15 min/fx.
Topics: Brachytherapy; Humans; Neoplasms; Organs at Risk; Radiotherapy Dosage; Radiotherapy Planning, Computer-Assisted; Rotation
PubMed: 26429274
DOI: 10.1118/1.4930807 -
Cancer Radiotherapie : Journal de La... Oct 2014Brachytherapy has come a long way from its beginnings nearly a century ago. In recent years, brachytherapy has become ever more sophisticated thanks to a multitude of... (Review)
Review
Brachytherapy has come a long way from its beginnings nearly a century ago. In recent years, brachytherapy has become ever more sophisticated thanks to a multitude of technological developments, including high-dose rate afterloading machines, image-guidance, and advanced planning systems. One of the advantages of brachytherapy, apart from the well-known capability of delivering highly conformal doses directly to the target, is that it is highly adaptable and can be used as a primary, adjunct, or salvage treatment. However, despite the existence of international treatment guidelines, the clinical practice of brachytherapy varies greatly by region, country, and even institution. In the present article, we provide an overview of recent findings from the Patterns of Care for Brachytherapy in Europe (PCBE) Study and we discuss new technologies used in brachytherapy and the emerging concept of "new biology" that supports the use of high-dose brachytherapy. Compared to the 1990s, the use of brachytherapy has increased substantially and it is expected to continue growing in the future as it becomes ever more precise and efficient.
Topics: Brachytherapy; Bystander Effect; Dose Fractionation, Radiation; Europe; Humans; Intraoperative Care; Neoplasms; Organs at Risk; Policy Making; Practice Guidelines as Topic; Practice Patterns, Physicians'; Radiation Oncology; Radiosurgery; Radiotherapy Dosage; Radiotherapy, Image-Guided; Signal Transduction; Surveys and Questionnaires
PubMed: 25175344
DOI: 10.1016/j.canrad.2014.07.143 -
Heart (British Cardiac Society) Jun 2005
Review
Topics: Brachytherapy; Coronary Restenosis; Drug Implants; Forecasting; Humans; Stents; Treatment Failure
PubMed: 15919650
DOI: 10.1136/hrt.2004.058891 -
Cancer Nov 1995With the discovery of radium by Curie in 1898, researchers recognized that this unique radionuclide had specific biologic properties that were applicable to treating... (Review)
Review
With the discovery of radium by Curie in 1898, researchers recognized that this unique radionuclide had specific biologic properties that were applicable to treating patients with cancer. In the beginning, the radium sources were placed within cavities as independent sources and, when needles were available, implanted into tissues. The first combination of brachytherapy, technologies with external-beam radiation therapy was reported by Wright at the Memorial Sloan-Kettering Cancer Center in New York in 1914 in the treatment of a patient with cervical cancer. Next, there was a rapid implementation of brachytherapy in the treatment of cancer by intracavitary placement of radionuclides, interstitial implantation technologies, and systemic administrations. With the development of new radionuclides, including cesium-137, cobalt-60, iridium-192, iodine-125, palladium-103, ruthenium-109, strontium-90, iodine-131, and californium-225, which had varying types of radiation emissions appropriate when properly selected in treatment of cancer, there was a rapid development of innovative technologies to treat all malignancies, especially gynecologic cancer. The evolution of events brought forth new applicators and techniques that allowed for better distribution of the radiation dosage within the tumor being treated, safer use of radionuclides, and the development of computer programs allowing for varying source applications and dose distributions within the volume implanted.
Topics: Brachytherapy; Female; Genital Neoplasms, Female; Humans
PubMed: 8635014
DOI: 10.1002/1097-0142(19951115)76:10+<2143::aid-cncr2820761339>3.0.co;2-4 -
Seminars in Radiation Oncology Jul 2000The goal of palliative radiation is to alleviate symptoms in a short amount of time and maintain an optimal functional and quality-of-life level while minimizing... (Review)
Review
The goal of palliative radiation is to alleviate symptoms in a short amount of time and maintain an optimal functional and quality-of-life level while minimizing toxicity and patient inconvenience. Despite advances in multimodality antineoplastic therapies, failure to control the tumor at its primary site frustratingly remains the predominant source of morbidity and mortality in many patients with cancer. Escalation of doses of radiation using external beam irradiation has been shown to improve local tumor control, but limits are imposed by the tolerance of normal surrounding structures. The highly conformal nature of brachytherapy enables the radiation oncologist to accomplish safe escalation of radiation doses to the tumor while minimizing doses to normal surrounding structures. Thus, by enhancing the potential for local control, brachytherapy used alone or as a supplement to external beam radiation therapy retains a significant and important role in achieving the goals of palliation. Proper patient selection, excellent technique, and adherence to implant rules will minimize the risk of complications. The advantages realized with the use of brachytherapy include good patient tolerance, short treatment time, and high rates of sustained palliation. This article reviews various aspects of palliative brachytherapy, including patient selection criteria, implant techniques, treatment planning, dose and fractionation schedules, results, and complications of treatment. Tumors of the head and neck, trachea and bronchi, esophagus, biliary tract, and brain, all in which local failure represents the predominant cause of morbidity and mortality, are highlighted.
Topics: Brachytherapy; Humans; Neoplasm Recurrence, Local; Neoplasms; Palliative Care; Patient Selection; Radiotherapy Dosage; Treatment Outcome
PubMed: 11034633
DOI: 10.1053/srao.2000.6723 -
International Journal of Radiation... Jul 2015Although brachytherapy had been established as a highly effective modality for the treatment of cancer, its application was threatened by mid-20th century due to... (Review)
Review
Although brachytherapy had been established as a highly effective modality for the treatment of cancer, its application was threatened by mid-20th century due to appreciation of the radiation hazard to health care workers. This review examines how the introduction of afterloading eliminated exposure and ushered in a brachytherapy renaissance.
Topics: Brachytherapy; History, 20th Century; Humans; Occupational Exposure; Radiation Injuries; Radioisotopes; Technology, Radiologic
PubMed: 26068477
DOI: 10.1016/j.ijrobp.2015.02.014 -
Clinical Oncology (Royal College of... Aug 2023Brachytherapy is an integral component of cancer care. Widespread concerns have been expressed though about the need for greater brachytherapy availability across many...
Brachytherapy is an integral component of cancer care. Widespread concerns have been expressed though about the need for greater brachytherapy availability across many jurisdictions. Yet, health services research in brachytherapy has lagged behind that in external beam radiotherapy. Optimal brachytherapy utilisation, to help inform expected demand, have not been defined beyond the New South Wales region in Australia, with few studies having reported observed brachytherapy utilisation. There is also a relative lack of robust cost and cost-effectiveness studies, making investment decisions in brachytherapy even more uncertain and challenging to justify, despite its key role in cancer control. As the range of indications for brachytherapy expands, providing organ/function preservation for a wider range of diagnoses, there is an urgent need to redress this balance. By outlining the work undertaken in this area to date, we highlight its importance and explore where further study is required.
Topics: Brachytherapy; Cost-Effectiveness Analysis; Australia; Health Services Needs and Demand; Humans; Neoplasms
PubMed: 36941146
DOI: 10.1016/j.clon.2023.03.001