# Cancer Treatment: An Overview of Pulsed Electric Field Utilization and Generation
## 10 The Feasibility and Utilization of PGs in Tumour Treatment  
Based on the presented PG classifications, classical PGs have a number of drawbacks: (1) long charging duration; (2) large volume and heavy weight; (3) limited controllability and lack of configuration or modification after design and construction. These limitations restrict repetition frequency and confine the resulting generators to unipolar pulses. These limitations make this category unsuitable and unsafe for clinical therapies. The resulting designs are non-portable and ill-suited for modern-day therapies, impacting patient well-being by limiting their daily activities.  
In contrast, SMPS-based PGs emerge as the most suitable category for portable devices, particularly for post-chemotherapy or radiotherapy TTF-based therapy. Examples include the portable devices produced by Novocure. SMPS designs are characterized by simplicity, minimal number of components, and lightweight construction, making them wearable, portable, and preferred by clinicians and patients alike. They allow patients to receive treatment while maintaining a normal lifestyle. These generators can be employed for LV short pulses with a high repetition frequency for RE applications such as the introduction of small molecules (i.e., electrochemotherapy by increasing membrane permeability to  
Figure 26: Parallel-input series-output inductive storage pulse generator.  
facilitate drug uptake). Devices based on SMPS can achieve a great success in the portable device market, especially when leveraging wide-bandgap GaN technology, which permits exceptionally high switching frequencies, superior performance, and reduced weight and losses.  
On the other hand, certain non-modular generators (CDVM and solid-state Marx) are complicated in terms of their design and control and utilize a high number of components with different ratings. However, these converters can charge their capacitors simultaneously, which reduces the charging time and increases the repetition frequency. Moreover, they can attain higher voltage levels and generate bipolar pulses with various shapes. Consequently, this category finds utility in generating HV short pulses for IRE applications such as induced cell death with short pulses, i.e., TTF as a monotherapy based on enhanced autophagy mechanism and initiating permanent pores in the cell membrane and internal organelles' membranes to prevent resealing.  
Capacitive voltage adder converters offer a host of advantages, including modularity, the capacity to reach higher plateau voltages, simultaneous charging of capacitors (resulting in increased repetition frequency), and ability to assemble modules of different voltage ratings in parallel branches to generate high/low voltage short/long pulses. This capability is invaluable, particularly for introducing large molecules into cells (e.g., DNA repair mechanisms), facilitating the generation of synergistic pulses.  
However, it is worth noting that while other modular generators such as MMC and cascaded H-bridge can achieve higher voltages, as can hybrid generators, they suffer from complexity, large size, and substantial weight. These generators are better suited for static non-movable devices intended for treatment in hospitals and care centers. These converters offer ease of configuration, scalability, modification, and upgradability thanks to their modular nature, providing the flexibility to generate various pulse shapes with adjustable parameters.