Related Experiment Video
Updated: Jun 9, 2026

10:16
Promoter Capture Hi-C: High-resolution, Genome-wide Profiling of Promoter Interactions
Published on: June 28, 2018
Don Lawrence and the "k-capture" revolution
1University of Massachusetts Medical School, Levine Cancer Center, Worcester, MA 01605, USA. aronowitz@radium-therapy.com
Brachytherapy
|August 28, 2010
Summary
Innovations in low-energy seeds revitalized brachytherapy, a cancer treatment. Donald Lawrence
Area of Science:
- Medical Physics
- Oncology
- Radiation Therapy
Background:
- Brachytherapy adoption declined mid-20th century due to safety concerns.
- Early brachytherapy techniques faced significant challenges.
Discussion:
- This article reviews innovations that revived brachytherapy.
- Focus is on low-energy seeds for permanent implantation, enhancing safety and efficacy.
Key Insights:
- Paul Harper proposed k-capture radionuclides in the 1950s.
- Donald Lawrence pioneered Iodine-125 (I-125) in the 1960s and Cesium-131 (Cs-131) later.
- Lawrence's work was crucial for modern brachytherapy seed development.
Outlook:
- Continued innovation in brachytherapy seeds promises improved cancer treatment outcomes.
- The legacy of Donald Lawrence highlights the impact of dedicated health physicists.
Related Concept Videos
Law of Independent Assortment
While Mendel’s Law of Segregation states that the two alleles for one gene are separated into different gametes, a different question of how different genes are inherited remains. For example, is the gene for tall plants inherited with the gene for green peas? Mendel asked this question by experimenting with a dihybrid cross; a cross in which both parents are homozygous for two distinct traits resulting in an F1 generation that are heterozygous for both traits.
Law of Independent Assortment
While Mendel’s Law of Segregation states that the two alleles for one gene are separated into different gametes, a different question of how different genes are inherited remains. For example, is the gene for tall plants inherited with the gene for green peas? Mendel asked this question by experimenting with a dihybrid cross; a cross in which both parents are homozygous for two distinct traits resulting in an F1 generation that are heterozygous for both traits.
Law of Effect
B.F. Skinner, a prominent figure in behavioral psychology, introduced operant conditioning by emphasizing the role of consequences in shaping behavior. This theory builds upon the law of effect proposed by Edward Thorndike, which posits that behaviors followed by satisfying outcomes are likely to be repeated. In contrast, those followed by unsatisfying outcomes are less likely to recur.
Edward Thorndike's foundational work involved studying learning in animals, particularly using puzzle boxes...
Edward Thorndike's foundational work involved studying learning in animals, particularly using puzzle boxes...
Kohlraush’s Law and its Applications
Kohlrausch's law explains that at infinite dilution, where dissociation is complete, each ion's contribution to the conductivity of the electrolyte is independent of the nature of other ions present in the solution. It also implies that when an electrolyte is highly diluted, the conductance of the electrolyte is the sum of the individual conductances of the ions it generates upon dissociation. The quantity of electricity an ion carries is proportional to its molar ionic conductance, which...
Lenz's Law
The direction in which the induced emf drives the current around a wire loop can be found through the negative sign. However, it is usually easier to determine this direction with Lenz's law, named in honor of its discoverer, Heinrich Lenz (1804–1865). Lenz's law states that the direction of the induced emf drives the current around a wire loop always to oppose the change in magnetic flux that causes the emf.
If a bar magnet is moved toward a coil such that the magnetic flux through the coil...
If a bar magnet is moved toward a coil such that the magnetic flux through the coil...
Law of Segregation
When crossing pea plants, Mendel noticed that one of the parental traits would sometimes disappear in the first generation of offspring, called the F1 generation, and could reappear in the next generation (F2). He concluded that one of the traits must be dominant over the other, thereby causing masking of one trait in the F1 generation. When he crossed the F1 plants, he found that 75% of the offspring in the F2 generation had the dominant phenotype, while 25% had the recessive phenotype.

