By type, parallel holes collimator segment dominated the market in 2019 and is expected to maintain its dominance at a CAGR of XX% during the forecast period. Parallel holes collimator is the most widely used type of collimator. It includes a lead plate in which all the holes are in parallel to each other. The parallel hole collimators are further divided into three types such as low energy all-purpose (LEAP), medium- and high energy and low energy high-resolution (LEHR) collimators. A surge in the adoption of parallel holes collimators in nuclear medicine imaging application to restrict the imaging field of view and to get extremely important data regarding the radioactivity distribution is attributed to the growth of the market.